Relevance of MUC1 mucin variable number of tandem repeats polymorphism in H pylori adhesion to gastric epithelial cells

AIM:To evaluate the influence of MUC1 mucin variable number of tandem repeats (VNTR) variability on H pylori adhesion to gastric cells. METHODS: Enzyme linked immunosorbent assay (ELISA)-based adhesion assays were performed to measure the adhesion of different H pylori strains (HP26695 and HPTx30a) to gastric carcinoma cell lines (GP202 and MKN45) and GP202 clones expressing recombinant MUC1 with different VNTR lengths. RESULTS: Evaluation of adhesion results shows that H pylori pathogenic strain HP26695 has a significantly higher (P < 0.05) adhesion to all the cell lines and clones tested, when compared to the non-pathogenic strain HPTx30a. Bacteria showed a significantly higher (P < 0.05) adhesion to the GP202 cell line, when compared to the MKN45 cell line. Furthermore, both strains showed a significantly higher (P < 0.05) adhesion to GP202 clones with larger MUC1 VNTR domains. CONCLUSION: This work shows that MUC1 mucin variability conditions H pylori binding to gastric cells. The extent of bacterial adhesion depends on the size of theMUC1 VNTR domain. The adhesion is further dependent on bacterial pathogenicity and the gastric cell line. MUC1 mucin variability may contribute to determine H pylori colonization of the gastric mucosa.

Broader pattern of tandem repeats in the mitochondrial control region of Perciformes

Perciformes,the largest order of vertebrates with 20 suborders,is the most diverse fish order that dominates vertebrate ocean life.The complete mitochondrial control region(CR) of Trichiurus japonicus(Trichiuridae,Scombroidei) and Pampus sp.(Stromateidae,Stromateoidei) were amplified and sequenced.Together with data from GenBank,the tandem repeats in the mitochondrial CR from 48 species,which covered nine suborders of Perciformes,are reported in this study.The tandem repeats tend to be long in the suborder Percoidei and Stromateoidei.The identical repeats in 21 species of Cichlidae suggest a common origin and have existed before species divergence.Larimichthys crocea shows tandem repeats instead of the typical structure of the central conserved sequence blocks,which was first reported in Perciformes and vertebrates.This might have resulted from interruption of the polymerase activity during the H-strand synthesis.The four broader patterns presented here for the tandem repeats,including those in both the 5' and 3' ends,only in the either 5' or 3' end,and in the central conserved domain of the control region,will be useful for understanding the evolution of species.

Identification and characterization of short tandem repeats in the Tibetan macaque genome based on resequencing data

The Tibetan macaque, which is endemic to China, is currently listed as a Near Endangered primate species by the International Union for Conservation of Nature （IUCN）（2017）. Short tandem repeats （STRs） refer to repetitive elements of genome sequence that range in length from 1-6 bp. They are found in many organisms and are widely applied in population genetic studies. To clarify the distribution characteristics of genome-wide STRs and understand their variation among Tibetan macaques, we conducted a genome-wide survey of STRs with next-generation sequencing of five macaque samples. A total of 1 077 790 perfect STRs were mined from our assembly, with an N50 of 4 966 bp. Mono-nucleotide repeats were the most abundant, followed by tetra- and di-nucleotide repeats. Analysis of GC content and repeats showed consistent results with other macaques. Furthermore, using STR analysis software （IobSTR）, we found that the proportion of base pair deletions in the STRs was greater than that of insertions in the five Tibetan macaque individuals （P〈0.05, t-test）. We also found a greater number of homozygous STRs than heterozygous STRs （P〈0.05, t-test）, with the Emei and Jianyang Tibetan macaques showing more heterozygous loci than Huangshan Tibetan macaques. The proportion of insertions and mean variation of alleles in the Emei and Jianyang individuals were slightly higher than those in the Huangshan individuals, thus revealing differences in STR allele size between the two populations The polymorphic STR loci identified based on the reference genome showed good amplification efficiency and could be used to study population genetics in Tibetan macaques. The neighbor-joining tree classified the five macaques into two different branches according to their geographical origin, indicating high genetic differentiation between the Huangshan and Sichuan populations. We elucidated the distribution characteristics of STRs in the Tibetan macaque genome and provided an effective method for screening polymorphic STRs. Our results also lay a foundation for future genetic variation studies of macaques.

Mapping short tandem repeats for liver gene expression traits helps prioritize potential causal variants for complex traits in pigs

Background:Short tandem repeats(STRs)were recently found to have significant impacts on gene expression and diseases in humans,but their roles on gene expression and complex traits in pigs remain unexplored.This study investigates the effects of STRs on gene expression in liver tissues based on the whole-genome sequences and RNA-Seq data of a discovery cohort of 260 F6 individuals and a validation population of 296 F7 individuals from a heterogeneous population generated from crosses among eight pig breeds.Results:We identified 5203 and 5868 significantly expression STRs(eSTRs,FDR<1%)in the F6 and F7 populations,respectively,most of which could be reciprocally validated(π1=0.92).The eSTRs explained 27.5%of the cisheritability of gene expression traits on average.We further identified 235 and 298 fine-mapped STRs through the Bayesian fine-mapping approach in the F6 and F7 pigs,respectively,which were significantly enriched in intron,ATAC peak,compartment A and H3K4me3 regions.We identified 20 fine-mapped STRs located in 100 kb windows upstream and downstream of published complex trait-associated SNPs,which colocalized with epigenetic markers such as H3K27ac and ATAC peaks.These included eSTR of the CLPB,PGLS,PSMD6 and DHDH genes,which are linked with genome-wide association study(GWAS)SNPs for blood-related traits,leg conformation,growth-related traits,and meat quality traits,respectively.Conclusions:This study provides insights into the effects of STRs on gene expression traits.The identified eSTRs are valuable resources for prioritizing causal STRs for complex traits in pigs.

Genetic Polymorphism of 38 Y-chromosome Short Tandem Repeats in Beijing Han Population from China

Objective:To investigate 38 Y-chromosome short tandem repeat(Y-STR)genetic polymorphisms in Beijing Han and analyze the genetic distance with neighboring or linguistically similar populations.Materials and Methods:In the study,we selected 531 unrelated male individuals of Beijing Han,and the results were statistically analyzed by testing with GSTAR™41Y reagents.Results:The allele peak heights were balanced among the Y loci,the amplified fragment ranged from 100 to 500 bps.A total of 531 haplotypes were detected in 531 samples.Eight null genotypes were observed on locus DYS448.One and three double alleles were observed on single-copy locus DYS576 and DYS19,respectively.DYS385 a/b,DYF387S1 a/b,and DYS527 a/b were more common in double copies,but 3,13,and 11 triple alleles were detected,respectively.The gene diversity values of Y-STRs except DYS391,DYS438,and DYS645 were>0.5.Twenty-seven Y-STRs of Beijing Han population were selected for genetic distance comparison with 17 populations including Changchun Han,with Rst values ranging from 0.0002 to 0.1703.Conclusion:The 38 Y-STRs in this study have strong male lineage identification ability and have great potential for individual identification,kinship identification,Y-STR database construction,and genetic relationship research.

Significant Deviations in the Configurations of Homologous Tandem Repeats in Prokaryotic Genomes

We explored the possibilities of whole-genome duplication （WGD） in prokaryotic species, where we performed statistical analyses of the configurations of the central angles between homologous tandem repeats （TRs） on the circular chromosomes. At first, we detected TRs on their chromosomes and identified equivalent tandem repeat pairs （ETRPs）; here, an ETRP is defined as a pair of tandem repeats sequentially similar to each other. Then we carried out statistical analyses of the central angle distributions of the detected ETRPs on each circular chromosome by way of comparisons between the detected distributions and those generated by null models. In the analyses, we estimated a P value by a simulation using the Kullback-Leibler divergence as a distance measure between two distributions. As a result, the central angle distributions for 8 out of the 203 prokaryotic species showed statistically significant deviations （P〈0.05）. In particular, we found out the characteristic feature of one round of WGD in Photorhabdus luminescens genome and that of two rounds of WGD in Escherichia coli K12.

Genetic and structural characterization of 20 autosomal short tandem repeats in the Chinese Qinghai Han population and its genetic relationships and interpopulation differentiations with other reference populations

China is a multinational country composed of 56 ethnic groups of which the Han Chinese accounts for 91.60%.Qinghai Province is located in the northeastern part of the Qinghai-Tibet Plateau,has an area of 72.12 km2,and is the fourth largest province in China.In the present study,we investigated the genetic polymorphisms of 20 short tandem repeat (STR) loci in a Qinghai Han population,as well as its genetic relationships with other populations.A total of 273 alleles were identified in 2 000 individuals at 20 loci,and the allelic frequency ranged from 0.0002 to 0.5327.The 20 STR loci showed a relatively high polymorphic rate in the studied group.Observed and expected heterozygosities ranged 0.613 0-0.907 5 and 0.614 8-0.920 0,respectively.The combined power of discrimination,and the probability of exclusion in duo and trio cases were 0.999 999 999 999 999 999 999 999 34,0.9999960 and 0.9999999965,respectively.Analyses of interpopulation differentiation revealed that the most significant differences were found between the Qinghai Han and Malaysian,while no significant differences were found between the Qinghai Han and Han people from Shaanxi and Jiangsu.The results of principal component analysis,multidimensional scaling analysis and phylogenetic reconstructions also suggested the close relationships between the Qinghai Han and other two Han populations.The present results,therefore,indicated that these 20 STR loci could be used for paternity testing and individual identification in forensic applications,and may also provide information for the studies of genetic relationships between Qinghai Han and other groups.

Identification of Half‑Sisters from Different Mothers by Autosomal and X Chromosomal Short Tandem Repeats:A Case Study

Complex kinship identification such as half‑sibling identification is a difficult task in forensic biology Here we represented an approach in dealing with half‑sisters from different mothers,with the combination of autosomal and X chromosomal short‑tandem repeats(STRs)data.X chromosomal STRs can offer additional information,especially in some cases where autosomal STRs alone may not provide enough information for an accurate opinion.In this case,half‑sister or unrelated relationship between two women(S_(1)and S_(2))with different mothers were distinguished.23 autosomal and 31 X chromosomal STRs of S_(1),S_(2),S_(1)’s mother(M1),S_(2)’s mother(M2)and S_(1)’s grandmother(G1)were profiled with three different commercial kits.As to X‑chromosome STRs,likelihood ratios(LRs)were calculated by FamLinkX with consideration of linkage,linkage disequilibrium,and mutations.When only the profiles of the two individuals(S_(1)and S_(2))were available,LRs between S_(1)and S_(2)were 1.1110×10^(2)based on 23 autosomal STRs and 3.2257 om107 based on 31 X chromosomal STRs.When the maternal genotypes were taken into consideration,LRs increased to 2.5297×10^(3)and 3.0563×10^(18).Therefore,both the DNA profiles of each mothers and X chromosomal STRs are important in dealing with the identification of half‑sisters from different mothers.

Application of Graph Entropy in CRISPR and Repeats Detection in DNA Sequences

We analyzed DNA sequences using a new measure of entropy. The general aim was to analyze DNA sequences and find interesting sections of a genome using a new formulation of Shannon like entropy. We developed this new measure of entropy for any non-trivial graph or, more broadly, for any square matrix whose non-zero elements represent probabilistic weights assigned to connections or transitions between pairs of vertices. The new measure is called the graph entropy and it quantifies the aggregate indeterminacy effected by the variety of unique walks that exist between each pair of vertices. The new tool is shown to be uniquely capable of revealing CRISPR regions in bacterial genomes and to identify Tandem repeats and Direct repeats of genome. We have done experiment on 26 species and found many tandem repeats and direct repeats (CRISPR for bacteria or archaea). There are several existing separate CRISPR or Tandem finder tools but our entropy can find both of these features if present in genome.

A NORTHWEST DATABASE MODEL OF SHORT TANDEM REPEAT LOCI IN FORENSIC MEDICINE

Objective To establish the northwest database of short tandem repeat(STR) loci in forensic medicine. Methods Bloodstains or whole blood samples were collected from the unrelated prisoners in Xi'an city. Genetic distribution for 13 STR loci and amelogenin locus were determined in prisons based on GeneScan. One primer for each locus was labeled with the fluorescent by 5 FAM, JOE, or NED. The forensic database were generated by using multiple amplification, GeneScan, genotype, and genetic distribution analysis. Results 113 alleles and 302 genotypes were observed, with the corresponding frequency between 0.0050-0.5250 and 0.0100-0.4100. The mean H was 0.7667. The accumulative DP was 0.9999999,. The accumulative EPP was 0.9999999. The scope of PIC was 0.6036- 0.8562 . PM was less than 10 -11 . The observed and expected genotype frequencies were evaluated using χ 2 test and all were in accordance with Hardy Weinberg equilibrium ( P > 0.05 ). Conclusion STR loci is an ideal genetic marker with powerful polymorphism and stable heredity. It can be used for individual identification and paternity in forensic medicine. The forensic DNA database model can be established successfully.

Carrier Detection and Presymptomatic Identification of Wilson Disease in Chinese by Non-Isotopic Linkage Analysis with Four Short Tandem Repeat Polymorphisms

Summary: Wilson disease (WD) is an autosomal recessive disorder of copper metabolism. To establish an efficient, accurate and fast diagnostic method for carrier detection and presymptomatic identification of WD in Chinese population, we studied haplotypes of short tandem repeat (STR) polymorphisms flanking the WD gene in 40 Chinese WD families. The results suggested that this genetic diagnosis system based on the four STR polymorphisms is of high value for the detection of potential carriers and WD homozygotes in families with at least one previously affected child. It is an efficient, accurate and fast diagnostic method that can be well suited for routine use in clinical laboratories.

Chromosomal localization of a tandemly repeated DNA sequence in Trifolium repens L

A karyotype of Trifolium repens constructed from mitotic cells revealed 13 pairs of metacentric and 3 pairs of submetacentric chromosomes including a pair of satellites located at the end of the short arm of chromosome 16.C-bands were identified around the centromeric regions of 8 pairs of chromosomes. A 350 bp tandemly repeated DNA sequence from T. repens labelled with digoxygenin hybridized to the proximal centromeric regions of 12 chromosome pairs. Some correlation between the distribution of the repeat sequence and the distribution of C-banding was demonstrated.

ALLELE DISTRIBUTION OF FIVE X-CHROMOSOME SHORT TANDEM REPEAT LOCI IN EWENKE POPULATION OF NORTH CHINA

Objective To study the allele genetic polymorphism of five short tandem repeat （STR） loci on X-chromosome in Ewenke population of north China and to provide basic data for forensic identification. Methods Genomic DNA was extracted from EDTA-whole blood of Ewenke population by Chelex-100. The DNA samples were amplified by PCR and were analyzed by polyacrylamide gel electrophoresis and silver staining. The sequence length variations of DXS6799, DXS8378, DXS101, HPRTB, and DXS6789 loci on X-chromosome in 98 unrelated Ewenke individuals were investigated. Results All five loci analyzed showed high polymorphism and genetic stability. The data of the five X-chromosome STR loci in Ewenke ethnic group of China was in accordance with Hardy-Weinberg equilibrium by Chi-square test. Conchusion Allele polymorphism of five X-chromosome STR loci can be used as a genetic marker for forensic identification and population genetic research.

Associations between IL-1RN variable number of tandem repeat, IL-1β (-511) and IL-1β (+3954) gene polymorphisms and urolithiasis in Uighur children of China

Objective:Interleukin-1(IL-1)is a pro-inflammatory cytokine which may be related to urolithiasis.Genetic polymorphisms of the interleukin-1beta(IL-1β)have been proposed as markers for urolithiasis in some areas.Due to the high incidence of urolithiasis in Uighur children(Xinjiang,China)and existence of ethnic difference,our aim is to explore the potential of IL-1 gene polymorphisms and urolithiasis among these children.Methods:Genomic DNA extracted from peripheral blood of 115 patients and 98 controls were used for genotype polymorphisms analyses.IL-1 receptor antagonist(IL-1RN)gene variable number of tandem repeat(VNTR)gene polymorphisms were analyzed by PCR method.PCR-based restriction analysis was done for the IL-1β(-511)and IL-1β(+3954)gene polymorphisms by endonucleases Ava I and Taq I,respectively.The genotype distribution,allele frequencies,carriage rate,and haplotype frequencies were statistically analyzed.Results:No significant differences were observed in genotypic frequencies between pediatric urolithiasis patients and control group for IL-1RN gene(χ^(2)=1.906,p=0.605),IL-1β(-511)gene(χ^(2)=0.105,p=0.949),or IL-1β(+3954)gene(χ^(2)=3.635,p=0.169).There were yet no significant differences of the allele frequencies of IL-1RN VNTR gene(p=0.779),IL-1β(-511)gene(p=0.941),and IL-1β(+3954)gene(p=0.418)in the case and control groups,as well as the carriage rate and haplotype of them(all p>0.05).Conclusions:The associations between IL-1RN VNTR,IL-1β(-511)and IL-1β(+3954)genes polymorphisms and urolithiasis were not significant in Uighur children.The results need to be confirmed in studies with larger population sample size,as well as in other ethnic groups.

TANDEM REPEATING OF THE EXPRESSIONCARTRIDGE──A NOVEL STRATEGY TOENHANCE THE EXPRESSION EFFICIENCY OFCLONED GENE IN ESCHERICHIA COLI

A novel strategy to enhance the expression efficiency of cloned target gene in Escherichia coli was developed. The whole expression cartridge , consisting of promoter. SD sequence , target gene and transcription terminator, was tandem repeatedly engineered into a expression plasmid. Consequently, the copy number of specific gene was increased substantially, leading to the improvement of expression efficiency.Using this approach, a recombinant plasmid , designed as PLYD, was constructed and transformated into the Escherichia coli strain DH5α. Upon induction , the desired protein was synthesized in a considerable level and accumulated up to 63% of the total cell proteins. The present study revealed that tandem repeating of expression cartridge provided a convenient means to improve expression level efficiently.

Application of Short Tandem Repeat in Prenatal Diagnosis for Phenmylketonuria during the First Trimester

Objective : To find a simple and rapid way far the prenatal diagnosis of phenyUce-tonuria (PKU) during the first trimester in order to prevent inborn PKU patients as early as possible. Methods :DNA was extracted respectively from the Mood sampleps of 9 families' members and chori-onic tissues of 9 embryoes by cliorionic vittus sampling (CVS). The independent short tandem repeat (STR) alleles of members in 9 families with classic form of PKU were analyzed and prenatal diagnosis were conducted using polymerase chain reaction (PCR) together with denaturing gradient gel elec-trophoresis(DGGE)and silver dyeing. Results-.We identified 1 embryo with PKU, 2 normal individuals and 5 carriers among 9 subjects. Conclusion: Prenatal diagnosis for PKU by STR is available in the first trimester. This procedure was promising and would be widely used in Chinese population.