Cis-regulatory elements regulate gene expression and play an essential role in the development and physiology of organisms.Many conserved non-coding sequences(CNSs)function as cis-regulatory elements.They control the ...Cis-regulatory elements regulate gene expression and play an essential role in the development and physiology of organisms.Many conserved non-coding sequences(CNSs)function as cis-regulatory elements.They control the development of various lineages.How-ever,predicting clade-wide cis-regulatory elements across several closely related species remains challenging.Based on the relationship between CNSs and cis-regulatory elements,we present a computational approach that predicts the clade-wide putative cis-regulatory elements in 12 Cucurbitaceae genomes.Using 12-way whole-genome alignment,we first obtained 632112 CNSs in Cucurbitaceae.Next,we identified 16552 Cucurbitaceae-wide cis-regulatory elements based on collinearity among all 12 Cucurbitaceae plants.Furthermore,we predicted 3271 potential regulatory pairs in the cucumber genome,of which 98 were verified using integrative RNA sequencing and ChIP sequencing datasets from samples collected during various fruit development stages.The CNSs,Cucurbitaceae-wide cis-regulatory elements,and their target genes are accessible at http://cmb.bnu.edu.cn/cisRCNEs_cucurbit/.These elements are valuable resources for functionally annotating CNSs and their regulatory roles in Cucurbitaceae genomes.展开更多
G-quadruplexes attract more and more attention in recent years.Numerous small molecules which can induce or stabilize the formation of G-quadruplexes have been investigated on the purpose of anticancer drug developmen...G-quadruplexes attract more and more attention in recent years.Numerous small molecules which can induce or stabilize the formation of G-quadruplexes have been investigated on the purpose of anticancer drug development.As a motif existed in physiological condition,flanking sequences are an important part of G-quadruplexes but the study on the impact of flanking sequences on (G-quadruplex)-ligand binding is rarely reported.In this paper,the effects of flanking sequences on binding affinity between a series of unimolecular parallel-stranded G-quadruplex sequences derived from c-myc oncogene promoter (termed as c-myc G-quadruplexes) and their ligands are discussed in detail.The results showed that the flanking sequences on c-myc G-quadruplexes play key roles in (G-quadruplex)-ligand interaction.When a c-myc G-quadruplex is bound to its ligands,the flanking sequences might form a binding cavity above the terminal G-quartet,which could provide a suitable site for ligands to dock in.Moreover,the bases on flanking sequences could interact with ligand through π-π stacking,and finally form a sandwich-stacking mode (terminal G-quartet,ligand and bases on the flanking sequence).This mode could stabilize the (G-quadruplex)-ligand complex effectively and enhance the binding affinity dramatically.However,flanking sequences are also found to exhibit steric hindrance effect which could impede the (G-quadruplex)-ligand binding.展开更多
The 5’-end of the mitochondrial control region sequences of three flatfishes (Pleuronectiformes: Pleuronectidae) were amplified and sequenced. These sequences were compared with those of other three Pleuronectids spe...The 5’-end of the mitochondrial control region sequences of three flatfishes (Pleuronectiformes: Pleuronectidae) were amplified and sequenced. These sequences were compared with those of other three Pleuronectids species retrieved from GenBank. A phylogenetic tree was constructed based on the partial control region sequences. The results of phyloge- netic analysis are consistent with those of conventional systematics. Compared to previous studies, the structure of the 5’-end of mitochondrial control region was analyzed. The terminal associated sequence motif and its complementary motif were i- dentified at the 5’-end of the sequences. A conserved sequence block, named as CM5’d, was identified in the 5’-end of con- trol region sequences in all Pleuronectids. Another central conserved sequence block, named as CSB-F, was detected in the central conserved blocks.展开更多
Inter-simple sequence repeat (ISSR) markers were used to determine the genetic variation and genetic differentiation of cultured and wild populations of Trachidermus fasciatus, an endangered catadromous fish species i...Inter-simple sequence repeat (ISSR) markers were used to determine the genetic variation and genetic differentiation of cultured and wild populations of Trachidermus fasciatus, an endangered catadromous fish species in China. Six selected primers were used to amplify DNA samples from 85 individuals, and 353 loci were detected. Relatively low genetic diversity was detected in the cultured population (the percentage of polymorphic loci PPL = 73.80%, Nei's gene diversity h = 0.178 2, Shannon information index I = 0.276 9). However, the genetic diversity at the species level was relatively high (PPL = 91.78%; h = 0.258 3, I = 0.398 6). The UPGMA tree grouped together the genotypes almost according to their cultured and wild origin, showing distinct differences in genetic structure between wild and cultured populations. The pairwise Fst values confirmed significant genetic differentiation between wild and cultured samples. The cultivated population seems to be low in genetic diversity as a result of detrimental genetic effects in the captive population. The results suggest that ISSR markers are effective for rapid assessment of the degree of diversity of a population, thus giving important topical information relevant to preserving endangered species.展开更多
Microsatellite markers were developed for Samadera bidwillii, a nationally listed vulnerable shrub or small tree, to enable investigation of its genetic structure and diversity within and among populations from its kn...Microsatellite markers were developed for Samadera bidwillii, a nationally listed vulnerable shrub or small tree, to enable investigation of its genetic structure and diversity within and among populations from its known distribution throughout coastal areas mainly in fragmented and disturbed lands from Mackay to Gympie, Queensland, Australia. The loci were tested for cross-amplification in related Samadera species. Ten polymorphic microsatellite markers were isolated and characterised from an enriched library of S. bidwillii, which exhibited di- and trinucleotide repeats. The mean number of alleles per locus ranged from 1.3 to 2.5 and mean expected and observed heterozygosities ranged from 0.06 to 0.33 and from 0.03 to 0.26, respectively in five populations. All loci successfully amplified in six other closely associated Samadera species also reported from Australia. Developed loci can be used in genetic diversity, population structure and gene flow studies with an emphasis on the conservation of S. bidwillii and related species.展开更多
BACKGROUND Since it is currently not possible to eradicate hepatitis B virus(HBV)infection with existing treatments,research continues to uncover new therapeutic strategies.HBV core protein,encoded by the HBV core gen...BACKGROUND Since it is currently not possible to eradicate hepatitis B virus(HBV)infection with existing treatments,research continues to uncover new therapeutic strategies.HBV core protein,encoded by the HBV core gene(HBC),intervenes in both structural and functional processes,and is a key protein in the HBV life cycle.For this reason,both the protein and the gene could be valuable targets for new therapeutic and diagnostic strategies.Moreover,alterations in the protein sequence could serve as potential markers of disease progression.AIM To detect,by next-generation sequencing,HBC hyper-conserved regions that could potentially be prognostic factors and targets for new therapies.METHODS Thirty-eight of 45 patients with chronic HBV initially selected were included and grouped according to liver disease stage[chronic hepatitis B infection without liver damage(CHB,n=16),liver cirrhosis(LC,n=5),and hepatocellular carcinoma(HCC,n=17)].HBV DNA was extracted from patients’plasma.A region between nucleotide(nt)1863 and 2483,which includes HBC,was amplified and analyzed by next-generation sequencing(Illumina Mi Seq platform).Sequences were genotyped by distance-based discriminant analysis.General and intergroup nt and amino acid(aa)conservation was determined by sliding window analysis.The presence of nt insertion and deletions and/or aa substitutions in the different groups was determined by aligning the sequences with genotype-specific consensus sequences.RESULTS Three nt(nt 1900-1929,2249-2284,2364-2398)and 2 aa(aa 117-120,159-167)hyper-conserved regions were shared by all the clinical groups.All groups showed a similar pattern of conservation,except for five nt regions(nt 1946-1992,2060-2095,2145-2175,2230-2250,2270-2293)and one aa region(aa 140-160),where CHB and LC,respectively,were less conserved(P<0.05).Some group-specific conserved regions were also observed at both nt(2306-2334 in CHB and 1935-1976 and 2402-2435 in LC)and aa(between aa 98-103 in CHB and 28-30 and 51-54 in LC)levels.No differences in insertion and deletions frequencies were observed.An aa substitution(P79 Q)was observed in the HCC group with a median(interquartile range)frequency of 15.82(0-78.88)vs 0(0-0)in the other groups(P<0.05 vs CHB group).CONCLUSION The differentially conserved HBC and HBV core protein regions and the P79 Q substitution could be involved in disease progression.The hyper-conserved regions detected could be targets for future therapeutic and diagnostic strategies.展开更多
We build a model of storage of well-defined positional information in probabilistic sequence patterns. Once a pattern is defined, it is possible to judge the effect of any mutation in it. We show that the frequency of...We build a model of storage of well-defined positional information in probabilistic sequence patterns. Once a pattern is defined, it is possible to judge the effect of any mutation in it. We show that the frequency of beneficial mutations can be high in general and the same mutation can be either advantageous or deleterious depending on the pattern’s context. The model allows to treat positional information as a physical quantity, formulate its conservation law and to model its continuous evolution in a whole genome, with meaningful applications of basic physical principles such as optimal efficiency and channel capacity. A plausible example of optimal solution analytically describes phase transitions-like behavior. The model shows that, in principle, it is possible to store error-free information on sequences with arbitrary low conservation. The described theoretical framework allows one to approach from novel general perspectives such long-standing paradoxes as excessive junk DNA in large genomes or the corresponding G- and C-values paradoxes. We also expect it to have an effect on a number of fundamental concepts in population genetics including the neutral theory, cost-of-selection dilemma, error catastrophe and others.展开更多
Recognition of CpG dinucleotide DNA in epigenetic information flow plays a pivotal role for cellular differentiation and development.The TET3 CXXC domain binds to CpG DNA,serving a basic epigenetic information reading...Recognition of CpG dinucleotide DNA in epigenetic information flow plays a pivotal role for cellular differentiation and development.The TET3 CXXC domain binds to CpG DNA,serving a basic epigenetic information reading mechanism.During the selective recognition of a CpG motif by a CXXC domain from crowded binding sites in a gene sequence,the protein-DNA interactions are beyond CpG dinu-cleotide.However,the selective binding dynamics of CpG within a long DNA context by epigenetic enzymes have been rarely exploit-ed,which is hard for ensemble methods to probe.Here,we used single-molecule magnetic tweezers to quantitatively examine the dynamics of TET3's CXXC domain on a Hoxa9 promoter DNA.Our single-molecule binding profile revealed that CXXC-DNA interactions involve both CpG motifs and their flanking sequences.The residence time of TET3 CXXC differs by about 1000 times in five distin-guished CpG clusters in the context of a CpG island.Moreover,we performed multi-state hidden Markov modeling analysis on the zip-ping/unzipping dynamics of a CpG hairpin,discovering TET3 CXXC's preference on CpG motifs regarding the-2 to+2 flanking bases.Our results shed light on the selective binding dynamics of a CXXC on a gene sequence,facilitating studies on epigenetic information reading mechanisms.展开更多
TaqMan quantitative PCR technique was used to detect the copies of exogenous CaMV35S flanks sequence in transgenic soybean. With soybean lectin as the endogenous reference gene, and gene complex DNA in non-GMO soybean...TaqMan quantitative PCR technique was used to detect the copies of exogenous CaMV35S flanks sequence in transgenic soybean. With soybean lectin as the endogenous reference gene, and gene complex DNA in non-GMO soybeans as the endogenous reference standard, the gradient dilution method was used to separately calculate Ct value of endogenous reference gene and plasmid DNA and correlation standard curve equation of logarithm of copies, and then to calculate the copies of samples through substituting thus-obtained Ct into the standard curve equation. The standard curve equation of endogenous reference gene was y =–3.422x+35.201, R2=0.998; the standard curve equation of exogenous gene was y =–3.495x+35.303, R2=0.999. The sample copies was got by putting Ct value into the standard curve equation, and it was the ratio of exogenous gene and reference gene. We found that CaMV35S gene in transgenic soy was single copy.展开更多
Population genomic data could provide valuable information for conservation efforts;however,limited studies have been conducted to investigate the genetic status of threatened pheasants.Reeves’s Pheasant(Syrmaticus r...Population genomic data could provide valuable information for conservation efforts;however,limited studies have been conducted to investigate the genetic status of threatened pheasants.Reeves’s Pheasant(Syrmaticus reevesii)is facing population decline,attributed to increases in habitat loss.There is a knowledge gap in understanding the genomic status and genetic basis underlying the local adaptation of this threatened bird.Here,we used population genomic data to assess population structure,genetic diversity,inbreeding patterns,and genetic divergence.Furthermore,we identified candidate genes linked with adaptation across the current distribution of Reeves’s Pheasant.The present study assembled the first de novo genome sequence of Reeves’s Pheasant and annotated 19,458 genes.We also sequenced 30 individuals from three populations(Dabie Mountain,Shennongjia,Qinling Mountain)and found that there was clear population structure among those populations.By comparing with other threatened species,we found that Reeves’s Pheasants have low genetic diversity.Runs of homozygosity suggest that the Shennongjia population has experienced serious inbreeding.The demographic history results indicated that three populations experienced several declines during the glacial period.Local adaptative analysis among the populations identified 241 candidate genes under directional selection.They are involved in a large variety of processes,including the immune response and pigmentation.Our results suggest that the three populations should be considered as three different conservation units.The current study provides genetic evidence for conserving the threatened Reeves’s Pheasant and provides genomic resources for global biodiversity management.展开更多
目的探讨两种较为公认但序列不同的Wiskott-Aldrich综合征蛋白和富含脯氨酸同源物(Wiskott-Aldrich syndrome protein and SCAR homolog,WASH)的差异。方法使用免疫荧光、免疫共沉淀和激光微辐射等实验分析两种WASH在定位模式、与FAM21...目的探讨两种较为公认但序列不同的Wiskott-Aldrich综合征蛋白和富含脯氨酸同源物(Wiskott-Aldrich syndrome protein and SCAR homolog,WASH)的差异。方法使用免疫荧光、免疫共沉淀和激光微辐射等实验分析两种WASH在定位模式、与FAM21或Ku蛋白的相互作用、向DNA损伤位点募集速率和蛋白质稳定性方面的差异;比较多种生物中的WASH蛋白质序列和检测多种在生物和医学研究中常用的细胞中的WASH编码序列,分析两种人WASH序列的普遍性和保守性。结果两种WASH展现出类似的内体(endosome)定位模式。WASH468表现出与FAM21更强的相互作用,并且WASH468展现出更强的稳定性。WASH465表现出与Ku蛋白更强的相互作用,并且WASH465展现出向DNA损伤位点更强的募集。多种生物中的WASH序列与人WASH468序列的一致性明显高于WASH465,并且多种在生物和医学研究中常用的细胞中的WASH氨基酸序列均与WASH468一致。结论WASH468和WASH465的生物学特性存在差异,WASH468序列的普遍性和保守性明显高于WASH465,因此WASH468是更保守的人WASH序列。展开更多
AIM To detect hyper-conserved regions in the hepatitis B virus(HBV) X gene(HBX) 5' region that could be candidates for gene therapy.METHODS The study included 27 chronic hepatitis B treatmentnaive patients in vari...AIM To detect hyper-conserved regions in the hepatitis B virus(HBV) X gene(HBX) 5' region that could be candidates for gene therapy.METHODS The study included 27 chronic hepatitis B treatmentnaive patients in various clinical stages(from chronic infection to cirrhosis and hepatocellular carcinoma, both HBeA g-negative and HBeA g-positive), and infected with HBV genotypes A-F and H. In a serum sample from each patient with viremia > 3.5 log IU/m L, the HBX 5' end region [nucleotide(nt) 1255-1611] was PCRamplified and submitted to next-generation sequencing(NGS). We assessed genotype variants by phylogenetic analysis, and evaluated conservation of this region by calculating the information content of each nucleotide position in a multiple alignment of all unique sequences(haplotypes) obtained by NGS. Conservation at the HBx protein amino acid(aa) level was also analyzed.RESULTS NGS yielded 1333069 sequences from the 27 samples, with a median of 4578 sequences/sample(2487-9279, IQR 2817). In 14/27 patients(51.8%), phylogenetic analysis of viral nucleotide haplotypes showed a complex mixture of genotypic variants. Analysis of the information content in the haplotype multiple alignments detected 2 hyper-conserved nucleotide regions, one in the HBX upstream non-coding region(nt 1255-1286) and the other in the 5' end coding region(nt 1519-1603). This last region coded for a conserved amino acid region(aa 63-76) that partially overlaps a Kunitz-like domain.CONCLUSION Two hyper-conserved regions detected in the HBX 5' end may be of value for targeted gene therapy, regardless of the patients' clinical stage or HBV genotype.展开更多
Agrobactedum tumefac/ens-mediated transformation (ATMT) is an efficient tool for insertional mutagenesis and is used in a wide variety of plants. This paper reports a promoter trapping method to generate mutants in ...Agrobactedum tumefac/ens-mediated transformation (ATMT) is an efficient tool for insertional mutagenesis and is used in a wide variety of plants. This paper reports a promoter trapping method to generate mutants in the filamentous fungus, Colletotrichum gloeosporioides, by ATMT insertion of a trapping vector (pCAHPH) that carries a promoterless hygromycin phosphotransferase (hph) gone. Transformants were selected on the media containing 200 ~mL hy^omycin B, and screened for pathogenicity-related gene mdtants. Their pathogenicity-related mutants T-DNA flanking sequences were then cloned and analyzed. Hph genes were amplified from mutant genomic DNA but not from wild-type DNA, indicating that the phenotypic alternations of these mutants were the results of T-DNA inser- tion. T-DNA flanking sequences were obtained using modified themud asymmetric interlaced PCR. Two right-sided flanking sequences were highly homologous to proteins from other species.展开更多
Gene flow between sympatric congeneric plants is thought to be very common and may pose serious threats to endangered species.In the present study,we evaluate the genetic diversity and divergence of three sympatric Rh...Gene flow between sympatric congeneric plants is thought to be very common and may pose serious threats to endangered species.In the present study,we evaluate the genetic diversity and divergence of three sympatric Rhododendron species in Jiaozi Mountain using newly developed microsatellites through the Illumina MiSeq sequencing approach.Genetic diversity of all three Rhododendron species studied was moderate in comparison to genetic parameters previously reported from species of this genus.Interestingly,genetic structure analysis of the three species identified a possible hybrid origin of the threatened Rh.pubicostatum.This sympatry should be considered a unimodal hybrid zone,since Rh.pubicostatum is predominant here.Unimodal hybrid zones are uncommon in Rhododendron,despite the fact that hybridization frequently occurs in the genus.Issues pertaining to the conservation of Rh.pubicostatum resulting from admixture of genetic material from its parental species are discussed.展开更多
基金supported by the National Natural Science Foundation of China(grant number:31571361).
文摘Cis-regulatory elements regulate gene expression and play an essential role in the development and physiology of organisms.Many conserved non-coding sequences(CNSs)function as cis-regulatory elements.They control the development of various lineages.How-ever,predicting clade-wide cis-regulatory elements across several closely related species remains challenging.Based on the relationship between CNSs and cis-regulatory elements,we present a computational approach that predicts the clade-wide putative cis-regulatory elements in 12 Cucurbitaceae genomes.Using 12-way whole-genome alignment,we first obtained 632112 CNSs in Cucurbitaceae.Next,we identified 16552 Cucurbitaceae-wide cis-regulatory elements based on collinearity among all 12 Cucurbitaceae plants.Furthermore,we predicted 3271 potential regulatory pairs in the cucumber genome,of which 98 were verified using integrative RNA sequencing and ChIP sequencing datasets from samples collected during various fruit development stages.The CNSs,Cucurbitaceae-wide cis-regulatory elements,and their target genes are accessible at http://cmb.bnu.edu.cn/cisRCNEs_cucurbit/.These elements are valuable resources for functionally annotating CNSs and their regulatory roles in Cucurbitaceae genomes.
基金Supported by the National Natural Science Foundation of China under Grant No.60772023by the Slpported Project under Grant No.SKLSDE-2010ZX-07 of the State Key Laboratory of Software Development Environment,Beijing University of Aeronautics and As tronautics+2 种基金by the Specialized Research Fund for the Doctoral Program of Higher Educatioi under Grant No.200800130006Chinese Ministry of Education,and by the Innovation Foundation for Ph.D.Graduates under Grant Nos.30-0350 and 30-0366Beijing University of Aeronautics and Astronautics
文摘G-quadruplexes attract more and more attention in recent years.Numerous small molecules which can induce or stabilize the formation of G-quadruplexes have been investigated on the purpose of anticancer drug development.As a motif existed in physiological condition,flanking sequences are an important part of G-quadruplexes but the study on the impact of flanking sequences on (G-quadruplex)-ligand binding is rarely reported.In this paper,the effects of flanking sequences on binding affinity between a series of unimolecular parallel-stranded G-quadruplex sequences derived from c-myc oncogene promoter (termed as c-myc G-quadruplexes) and their ligands are discussed in detail.The results showed that the flanking sequences on c-myc G-quadruplexes play key roles in (G-quadruplex)-ligand interaction.When a c-myc G-quadruplex is bound to its ligands,the flanking sequences might form a binding cavity above the terminal G-quartet,which could provide a suitable site for ligands to dock in.Moreover,the bases on flanking sequences could interact with ligand through π-π stacking,and finally form a sandwich-stacking mode (terminal G-quartet,ligand and bases on the flanking sequence).This mode could stabilize the (G-quadruplex)-ligand complex effectively and enhance the binding affinity dramatically.However,flanking sequences are also found to exhibit steric hindrance effect which could impede the (G-quadruplex)-ligand binding.
基金the Shandong Foundation of Sciences(No.Y2000D04) the National Key Basic Research Program from the Ministry of Science and Technology of China(No.G19990437).
文摘The 5’-end of the mitochondrial control region sequences of three flatfishes (Pleuronectiformes: Pleuronectidae) were amplified and sequenced. These sequences were compared with those of other three Pleuronectids species retrieved from GenBank. A phylogenetic tree was constructed based on the partial control region sequences. The results of phyloge- netic analysis are consistent with those of conventional systematics. Compared to previous studies, the structure of the 5’-end of mitochondrial control region was analyzed. The terminal associated sequence motif and its complementary motif were i- dentified at the 5’-end of the sequences. A conserved sequence block, named as CM5’d, was identified in the 5’-end of con- trol region sequences in all Pleuronectids. Another central conserved sequence block, named as CSB-F, was detected in the central conserved blocks.
基金Supported by the Key Laboratory of Freshwater Biodiversity Conservation and Utilization, Ministry of Agriculture (No. LFBCU0713)the Special Research Foundation for Public Welfare Marine Program (No. 200905019-2)
文摘Inter-simple sequence repeat (ISSR) markers were used to determine the genetic variation and genetic differentiation of cultured and wild populations of Trachidermus fasciatus, an endangered catadromous fish species in China. Six selected primers were used to amplify DNA samples from 85 individuals, and 353 loci were detected. Relatively low genetic diversity was detected in the cultured population (the percentage of polymorphic loci PPL = 73.80%, Nei's gene diversity h = 0.178 2, Shannon information index I = 0.276 9). However, the genetic diversity at the species level was relatively high (PPL = 91.78%; h = 0.258 3, I = 0.398 6). The UPGMA tree grouped together the genotypes almost according to their cultured and wild origin, showing distinct differences in genetic structure between wild and cultured populations. The pairwise Fst values confirmed significant genetic differentiation between wild and cultured samples. The cultivated population seems to be low in genetic diversity as a result of detrimental genetic effects in the captive population. The results suggest that ISSR markers are effective for rapid assessment of the degree of diversity of a population, thus giving important topical information relevant to preserving endangered species.
文摘Microsatellite markers were developed for Samadera bidwillii, a nationally listed vulnerable shrub or small tree, to enable investigation of its genetic structure and diversity within and among populations from its known distribution throughout coastal areas mainly in fragmented and disturbed lands from Mackay to Gympie, Queensland, Australia. The loci were tested for cross-amplification in related Samadera species. Ten polymorphic microsatellite markers were isolated and characterised from an enriched library of S. bidwillii, which exhibited di- and trinucleotide repeats. The mean number of alleles per locus ranged from 1.3 to 2.5 and mean expected and observed heterozygosities ranged from 0.06 to 0.33 and from 0.03 to 0.26, respectively in five populations. All loci successfully amplified in six other closely associated Samadera species also reported from Australia. Developed loci can be used in genetic diversity, population structure and gene flow studies with an emphasis on the conservation of S. bidwillii and related species.
基金Supported by the Instituto de Salud CarlosⅢ,Spain,the European Regional Development Fund,No.PI18/01436。
文摘BACKGROUND Since it is currently not possible to eradicate hepatitis B virus(HBV)infection with existing treatments,research continues to uncover new therapeutic strategies.HBV core protein,encoded by the HBV core gene(HBC),intervenes in both structural and functional processes,and is a key protein in the HBV life cycle.For this reason,both the protein and the gene could be valuable targets for new therapeutic and diagnostic strategies.Moreover,alterations in the protein sequence could serve as potential markers of disease progression.AIM To detect,by next-generation sequencing,HBC hyper-conserved regions that could potentially be prognostic factors and targets for new therapies.METHODS Thirty-eight of 45 patients with chronic HBV initially selected were included and grouped according to liver disease stage[chronic hepatitis B infection without liver damage(CHB,n=16),liver cirrhosis(LC,n=5),and hepatocellular carcinoma(HCC,n=17)].HBV DNA was extracted from patients’plasma.A region between nucleotide(nt)1863 and 2483,which includes HBC,was amplified and analyzed by next-generation sequencing(Illumina Mi Seq platform).Sequences were genotyped by distance-based discriminant analysis.General and intergroup nt and amino acid(aa)conservation was determined by sliding window analysis.The presence of nt insertion and deletions and/or aa substitutions in the different groups was determined by aligning the sequences with genotype-specific consensus sequences.RESULTS Three nt(nt 1900-1929,2249-2284,2364-2398)and 2 aa(aa 117-120,159-167)hyper-conserved regions were shared by all the clinical groups.All groups showed a similar pattern of conservation,except for five nt regions(nt 1946-1992,2060-2095,2145-2175,2230-2250,2270-2293)and one aa region(aa 140-160),where CHB and LC,respectively,were less conserved(P<0.05).Some group-specific conserved regions were also observed at both nt(2306-2334 in CHB and 1935-1976 and 2402-2435 in LC)and aa(between aa 98-103 in CHB and 28-30 and 51-54 in LC)levels.No differences in insertion and deletions frequencies were observed.An aa substitution(P79 Q)was observed in the HCC group with a median(interquartile range)frequency of 15.82(0-78.88)vs 0(0-0)in the other groups(P<0.05 vs CHB group).CONCLUSION The differentially conserved HBC and HBV core protein regions and the P79 Q substitution could be involved in disease progression.The hyper-conserved regions detected could be targets for future therapeutic and diagnostic strategies.
文摘We build a model of storage of well-defined positional information in probabilistic sequence patterns. Once a pattern is defined, it is possible to judge the effect of any mutation in it. We show that the frequency of beneficial mutations can be high in general and the same mutation can be either advantageous or deleterious depending on the pattern’s context. The model allows to treat positional information as a physical quantity, formulate its conservation law and to model its continuous evolution in a whole genome, with meaningful applications of basic physical principles such as optimal efficiency and channel capacity. A plausible example of optimal solution analytically describes phase transitions-like behavior. The model shows that, in principle, it is possible to store error-free information on sequences with arbitrary low conservation. The described theoretical framework allows one to approach from novel general perspectives such long-standing paradoxes as excessive junk DNA in large genomes or the corresponding G- and C-values paradoxes. We also expect it to have an effect on a number of fundamental concepts in population genetics including the neutral theory, cost-of-selection dilemma, error catastrophe and others.
基金Professor Chao Xu of the University of Science and Technology of China(UsTC)for constructive discussions.We acknowledge support from the National Natural Science Foundation of China[Grant 32071227 to Z.Y.]State Key Laboratory of Precision Measuring Technology and Instruments(Tianjin University)[Grant pilab2210 to Z.Y.]+1 种基金the Natural Science Foundation of Tianjin[Grant 22JCYBJC01070 to Z.Y.]the Science and Technology Innovation Program of Shanxi Agricultural University[Grant 2022BQ23 to L.L.].
文摘Recognition of CpG dinucleotide DNA in epigenetic information flow plays a pivotal role for cellular differentiation and development.The TET3 CXXC domain binds to CpG DNA,serving a basic epigenetic information reading mechanism.During the selective recognition of a CpG motif by a CXXC domain from crowded binding sites in a gene sequence,the protein-DNA interactions are beyond CpG dinu-cleotide.However,the selective binding dynamics of CpG within a long DNA context by epigenetic enzymes have been rarely exploit-ed,which is hard for ensemble methods to probe.Here,we used single-molecule magnetic tweezers to quantitatively examine the dynamics of TET3's CXXC domain on a Hoxa9 promoter DNA.Our single-molecule binding profile revealed that CXXC-DNA interactions involve both CpG motifs and their flanking sequences.The residence time of TET3 CXXC differs by about 1000 times in five distin-guished CpG clusters in the context of a CpG island.Moreover,we performed multi-state hidden Markov modeling analysis on the zip-ping/unzipping dynamics of a CpG hairpin,discovering TET3 CXXC's preference on CpG motifs regarding the-2 to+2 flanking bases.Our results shed light on the selective binding dynamics of a CXXC on a gene sequence,facilitating studies on epigenetic information reading mechanisms.
基金Supported by the Program of Technology Bureau of Harbin (2010RFQXN101)the Subproject of Transgenic Significant Specific Project (20112X08004-002-002-004)
文摘TaqMan quantitative PCR technique was used to detect the copies of exogenous CaMV35S flanks sequence in transgenic soybean. With soybean lectin as the endogenous reference gene, and gene complex DNA in non-GMO soybeans as the endogenous reference standard, the gradient dilution method was used to separately calculate Ct value of endogenous reference gene and plasmid DNA and correlation standard curve equation of logarithm of copies, and then to calculate the copies of samples through substituting thus-obtained Ct into the standard curve equation. The standard curve equation of endogenous reference gene was y =–3.422x+35.201, R2=0.998; the standard curve equation of exogenous gene was y =–3.495x+35.303, R2=0.999. The sample copies was got by putting Ct value into the standard curve equation, and it was the ratio of exogenous gene and reference gene. We found that CaMV35S gene in transgenic soy was single copy.
基金supported by the Biodiversity Survey,Monitoring and Assessment Project(2019–2023)of the Ministry of Ecology and EnvironmentChina(No.2019HB2096001006 to ZZ)+2 种基金the National Natural Science Foundation of China(31672319)Endangered Species Scientific Commission of China(No.2022–331)supported by the China Scholarship Council,China。
文摘Population genomic data could provide valuable information for conservation efforts;however,limited studies have been conducted to investigate the genetic status of threatened pheasants.Reeves’s Pheasant(Syrmaticus reevesii)is facing population decline,attributed to increases in habitat loss.There is a knowledge gap in understanding the genomic status and genetic basis underlying the local adaptation of this threatened bird.Here,we used population genomic data to assess population structure,genetic diversity,inbreeding patterns,and genetic divergence.Furthermore,we identified candidate genes linked with adaptation across the current distribution of Reeves’s Pheasant.The present study assembled the first de novo genome sequence of Reeves’s Pheasant and annotated 19,458 genes.We also sequenced 30 individuals from three populations(Dabie Mountain,Shennongjia,Qinling Mountain)and found that there was clear population structure among those populations.By comparing with other threatened species,we found that Reeves’s Pheasants have low genetic diversity.Runs of homozygosity suggest that the Shennongjia population has experienced serious inbreeding.The demographic history results indicated that three populations experienced several declines during the glacial period.Local adaptative analysis among the populations identified 241 candidate genes under directional selection.They are involved in a large variety of processes,including the immune response and pigmentation.Our results suggest that the three populations should be considered as three different conservation units.The current study provides genetic evidence for conserving the threatened Reeves’s Pheasant and provides genomic resources for global biodiversity management.
文摘目的探讨两种较为公认但序列不同的Wiskott-Aldrich综合征蛋白和富含脯氨酸同源物(Wiskott-Aldrich syndrome protein and SCAR homolog,WASH)的差异。方法使用免疫荧光、免疫共沉淀和激光微辐射等实验分析两种WASH在定位模式、与FAM21或Ku蛋白的相互作用、向DNA损伤位点募集速率和蛋白质稳定性方面的差异;比较多种生物中的WASH蛋白质序列和检测多种在生物和医学研究中常用的细胞中的WASH编码序列,分析两种人WASH序列的普遍性和保守性。结果两种WASH展现出类似的内体(endosome)定位模式。WASH468表现出与FAM21更强的相互作用,并且WASH468展现出更强的稳定性。WASH465表现出与Ku蛋白更强的相互作用,并且WASH465展现出向DNA损伤位点更强的募集。多种生物中的WASH序列与人WASH468序列的一致性明显高于WASH465,并且多种在生物和医学研究中常用的细胞中的WASH氨基酸序列均与WASH468一致。结论WASH468和WASH465的生物学特性存在差异,WASH468序列的普遍性和保守性明显高于WASH465,因此WASH468是更保守的人WASH序列。
基金Supported by the Instituto de Salud Carlos III,No.PI15/00856the European Regional Development Fund(ERDF),No.PI15/00856
文摘AIM To detect hyper-conserved regions in the hepatitis B virus(HBV) X gene(HBX) 5' region that could be candidates for gene therapy.METHODS The study included 27 chronic hepatitis B treatmentnaive patients in various clinical stages(from chronic infection to cirrhosis and hepatocellular carcinoma, both HBeA g-negative and HBeA g-positive), and infected with HBV genotypes A-F and H. In a serum sample from each patient with viremia > 3.5 log IU/m L, the HBX 5' end region [nucleotide(nt) 1255-1611] was PCRamplified and submitted to next-generation sequencing(NGS). We assessed genotype variants by phylogenetic analysis, and evaluated conservation of this region by calculating the information content of each nucleotide position in a multiple alignment of all unique sequences(haplotypes) obtained by NGS. Conservation at the HBx protein amino acid(aa) level was also analyzed.RESULTS NGS yielded 1333069 sequences from the 27 samples, with a median of 4578 sequences/sample(2487-9279, IQR 2817). In 14/27 patients(51.8%), phylogenetic analysis of viral nucleotide haplotypes showed a complex mixture of genotypic variants. Analysis of the information content in the haplotype multiple alignments detected 2 hyper-conserved nucleotide regions, one in the HBX upstream non-coding region(nt 1255-1286) and the other in the 5' end coding region(nt 1519-1603). This last region coded for a conserved amino acid region(aa 63-76) that partially overlaps a Kunitz-like domain.CONCLUSION Two hyper-conserved regions detected in the HBX 5' end may be of value for targeted gene therapy, regardless of the patients' clinical stage or HBV genotype.
基金Supported by the Key Projects in Hainan Province(090141)National Natural Science Fund(31101408)
文摘Agrobactedum tumefac/ens-mediated transformation (ATMT) is an efficient tool for insertional mutagenesis and is used in a wide variety of plants. This paper reports a promoter trapping method to generate mutants in the filamentous fungus, Colletotrichum gloeosporioides, by ATMT insertion of a trapping vector (pCAHPH) that carries a promoterless hygromycin phosphotransferase (hph) gone. Transformants were selected on the media containing 200 ~mL hy^omycin B, and screened for pathogenicity-related gene mdtants. Their pathogenicity-related mutants T-DNA flanking sequences were then cloned and analyzed. Hph genes were amplified from mutant genomic DNA but not from wild-type DNA, indicating that the phenotypic alternations of these mutants were the results of T-DNA inser- tion. T-DNA flanking sequences were obtained using modified themud asymmetric interlaced PCR. Two right-sided flanking sequences were highly homologous to proteins from other species.
基金Science and Technology Basic Resources Investigation Program of China(Grant No.2017FY100100)the Second Tibetan Plateau Scientific Expedition and Research(STEP)Program(Grant No.2019QZKK0502)+2 种基金the Young Academic and Technical Leader Raising Foundation of Yunnan Province(No.2018HB066)Yunnan Innovation Team Program for Conservation and Utilization of PSESP(Plant Species with Extremely Small Populations)(Grant No.2019HC015)Applied Basic Research Project of Yunnan Province(Grant No.2018BB010).
文摘Gene flow between sympatric congeneric plants is thought to be very common and may pose serious threats to endangered species.In the present study,we evaluate the genetic diversity and divergence of three sympatric Rhododendron species in Jiaozi Mountain using newly developed microsatellites through the Illumina MiSeq sequencing approach.Genetic diversity of all three Rhododendron species studied was moderate in comparison to genetic parameters previously reported from species of this genus.Interestingly,genetic structure analysis of the three species identified a possible hybrid origin of the threatened Rh.pubicostatum.This sympatry should be considered a unimodal hybrid zone,since Rh.pubicostatum is predominant here.Unimodal hybrid zones are uncommon in Rhododendron,despite the fact that hybridization frequently occurs in the genus.Issues pertaining to the conservation of Rh.pubicostatum resulting from admixture of genetic material from its parental species are discussed.