Accumulation of Mutant Genes and Its Pathway with Reproductive Isolation

According to the fitness of heterozygote was lower than homozygote among panmictic population,the process of generational accumulate of mutant gene r was considered.Branch point of r＇s frequency by generational evolution which revealed the hereditary incompatibility between R and r,was worked out,and it was found that genetic drift can make r have higher frequency to surpass the branch point to form reproductive isolation.It was not enough to have the three conditions of mutation,genetic drift and natural selection to be the drive of biological evolution;hybrid weakness,the repelling interaction between the genetic background of original population and the new mutation,were also needed.

Nutritional Quality of the Maize Combinations with Mutant Gene opaque-2 (o2)

[Objective] This study aimed to investigate the action of mutant gene o2 and its effect on nutritional quality of different maize combinations. [Method] A total of 33 normal maize combinations from 18 inbred lines were compared with 33 combinations including gene o2 from the corresponding o2 near-isogenic lines （o2-NILs）, to study the effect of o2 gene introduction on maize grain quality. [Result] The contents of lysine, protein and oil in o2-NILs were greatly more than that of normal maize combinations. Except for lysine, contents of other 14 amino acids changed when o2 gene was introduced. Contents of aspartic acid, threonine, glycine, isoleucine, histidine, arginine and proline were improved; while contents of serine, glutamic acid, alanine, valine, leucine, tyrosine and phenylalanine were decreased. Correlation analysis showed that contents of aspartic acid, arginine and threonine had the highest correlation with lysine content. Protein and oil contents had higher correlation with lysine content （0.48 and 0.38）. Analysis of 33 o2-NILs revealed that the o2 combinations CAL58×Ji477and CA156×196 showed high comprehensive quality and high yield with greater development potential. [Conclusion] This study will provide theoretical and material basis for improving the quality of temperate maize germplasm by introducing o2 gene.

Transferring Translucent Endosperm Mutant Gene Wx-mq and Rice Stripe Disease Resistance Gene Stv-bi by Marker-Assisted Selection in Rice (Oryza sativa)

A high-yielding japonica rice variety, Wuyunjing 7, bred in Jiangsu Province, China as a female parent was crossed with a Japanese rice variety Kantou 194, which carries a rice stripe disease resistance gene Stv-b＇ and a translucent endosperm mutant gene Wx-mq. From F2 generations, a sequence characterized amplified region （SCAR） marker tightly linked with Stv-b＇ and a cleaved amplified polymorphic sequence （CAPS） marker for Wx-mq were used for marker-assisted selection. Finally, a new japonica rice line, Ning 9108, with excellent agronomic traits was obtained by multi-generational selection on stripe disease resistance and endosperm appearance. The utilization of the markers from genes related to rice quality and disease resistance was helpful not only for establishing a marker-assisted selection system of high-quality and disease resistance for rice but also for providing important intermediate materials and rapid selection method for good quality, disease resistance and high yield in rice breeding.

In Vitro Anti-tumor Immune Response Induced by Dendritic Cells Transfected with Recombinant Adenovirus Carrying Mutant K-ras Genes

Summary： The specific anti-tumor immune response induced by mouse bone marrow dendritic cells （DCs） lransfected with recombinant adenovirus carrying mutant k-ras genes was investighted. DCs were generated from mouse bone marrow in the presence of rmGM-CSF （3.3 ng/mL） and rmIL-4 （1.3 ng/mL） and detected by FACS, and then transfecled with the recombinant adenovirus encoding mutant k ras gene. The efficacy of transfection and T cell stimulating activity of DCs were detected. CTL activity of the mice vaccinated with DCs was observed. The resuhs showed thai DCs had dendritic veiled morphology. BmDCs highly expressed B7-1（80%）, B7-2（77%）, MHC Ⅱ （70%）, CDllc （65%）, CD40 （70%） and CD54 （96%） with FACS, and no significant difference in the expression was observed before and after the transfection （P〈0.05）. The DCs transfeeled by mutant k-ras gene could significantly stimulate lymphoeytes proliferation as compared with those transfeeted by Ad e or non-modified DCs （P〈0.05）. DC vaccine transfected by mutant k-ras gene could induce CTL activity against Lewis lung cancer, but not against B16. The specific eytotoxicity against Lewis lung cancer in Ad-k-ras/12-transdueed DC group was signifieantly higher than those in the control, vector and non transfeeted DCs groups （P〈0.05）. It was concluded that special antitumor response could be induced by DCs transfected with recombinant adenovirus carrying mutant k-ras genes.

Experimental research for specific down-regulated expression of p53 gene by individual antisense RNA in vitro

Objective： To investigate the specific blockage effect of individual antisense RNA on mutant p53 gene in vitro. Methods： The single strand antisense transcription system containing mt-p53 exon 8 sequence （pGEM3zf（＋/-）p53exon8） was constructed. The ligation of antisense RNAwith mt-p53 gene was confirmed by in situ hybridization; MDA-MB-231 human breast cancer cells were transfected with ASp53exon8＇RNA cotionic liposome-mediated. Expression of mt-p53 protein was examined by immunocytochemical staining and Western blot. Cell proliferation was evaluated by MTT assay; Cell cycle distribution was determined by flow cytometry （FCM）; Apoptosis was observed by TUNEL. Results： In transfected MDA-MB-231 cells, hybridization signals were observed in cytoplasm. ASp53exon8＇RNA transfection induced inhibition of cell proliferation, G2/M phase arrest and increasing apoptotic rates. In addition, expression of p53 protein was down-regulated. Conclusion： pGEM3zf（＋/-）p53exon8 was well constructed and ASp53exon8＇RNA can block mt-p53 gene expression specifically and then inhibit MDA-MB-231 cell proliferation in vitro, which may serve as therapeutic means for human malignancy.

A Mutant Gene Found to Be the Pathogenic Origin of Infantile Cataract

According to a report in the June 24 issue of Nature Genetics, mutations in a gene named heat-shock transcription factor 4 (HSF4) have been discovered to be responsible for lamellar and Marner cataract. Experts believe that this will open new horizons for revealing the pathogenic origin of congenital cataract. ……

A recurrent G367R mutation in MYOC associated with juvenile open angle glaucoma in a large Chinese family

AIM： To identify the mutations of MYOC, OPTN, CYPIB1 and WDR36 in a large Chinese family affected by juvenile open angle glaucoma （JOAG）. METHODS： Of 114 members of one family were recruited in this study. Blood samples from twelve members of this pedigree were collected for further research. As a control, 100 unrelated subjects were recruited from the same hospital. The exon and flanking intron sequences of candidate genes were amplified using the polymerase chain reaction and direct DNA sequencing. RESULTS： The proband （111：10） was a seventy-three years old woman with binocular JOAG at the age of 31. A recurrent heterozygous mutation （c.1099G〉A） of MYOC was identified in the three JOAG patients and another suspect. This transition was located in the first base pair of codon 367 （GGA〉AGA） in exon 3 of MYOC and was predicted to be a missense substitution of glycine to arginine （p.G367R） in myocilin. Mutations in OPTN, CYPIB1 or WDR36 were not detected in this study. The G367R mutation was not present in unaffected family members or in 100 ethnically matched controls. Other variants of the coding regions of candidate genes were not detected in all participants. To date, this family was the largest to have been identified as carrying a certain MYOC mutation in China, further evidence of a founder effect for the G367R MYOC mutant was provided by our data. CONCLUSION： A MYOC c.1099G〉A mutation in an autosomal dominant JOAG family is identified and the characteristic phenotypes among the patients are summarized. Genetic testing could be utilized in high-risk populations and be helpful not only for genetic counseling, but also for early diagnosis and treatment of affected patients or carriers of inherited JOAG.

A Point Mutation in an F-Box Domain-Containing Protein Is Responsible for Brown Hull Phenotype in Rice

The accumulation of pigments affects the color of rice hulls while only limited information is known about its underlying mechanisms. In the present study, a rice brown hull 6（bh6） mutant was isolated from an ethane methyl sulfonate（EMS）-induced IR64 mutant bank. Brown pigments started to accumulate in bh6 rice hulls after heading and reached a higher level in mature seeds. Some major agronomic traits including panicle length and 1000-grain weight in bh6 were significantly lower than those in its corresponding wild type IR64, while other agronomic traits such as plant height, growth duration and seed-setting rate were largely similar between the two genotypes. The analysis of pigment content showed that the contents of total flavonoids and anthocyanin in bh6 hulls were significantly higher than those in IR64 hulls. Our results showed that the brown hull phenotype in bh6 was controlled by a single recessive gene which locates on the long arm of chromosome 9. Sequencing analysis detected a single base substitution（G/A） at position 1013 of the candidate gene（LOC_Os09g12150） encoding an F-box domain-containing protein（FBX310）. Functional complementation experiment using the wild type allele can rescue the phenotype in bh6. Thus, we named this mutated gene as Os FBX310^（bh6）, an allele of OsFBX310 functioning as an inhibitor of brown hull. The isolation of Os FBX310^（bh6） and its wild type allele can provide useful experimental materials and will facilitate the studies on revealing the mechanisms of flavonoid metabolism in monocot plants.

Progress in target therapy of advanced non-small cell lung cancer

Lung cancer is one of the most common malignant tumors,and its morbidity and mortality are relatively high.Especially for small cell lung cancer(SCLC),the mortality rate is between 80-90%.Unfortunately,more than 50%of lung cancer patients are diagnosed at an advanced stage.The traditional treatment for advanced non-small cell lung cancer(NSCLC)is chemotherapy.In recent years,with the rapid development of molecular pathology,we have a deeper understanding of the underlying pathological mechanism and heterogeneity of lung cancer,especially NSCLC.Molecular targeted therapy is more accurate because of its anti-tumor effect,and the incidence of adverse drug reactions is low.Compared with chemotherapy in the traditional sense,the degree of damage to normal tissues is also significantly reduced.Therefore,it has become a research hotspot in recent years.This article reviews the research progress of various molecular targeted drugs for the treatment of lung cancer based on domestic and foreign research literature and related data.

Hepatitis B virus S gene mutants in infants infected despite immunoprophylaxis

Objective To assess the correlation between hepatitis B virus (HBV) surface gene mutant infection and hepatitis B (HB) vaccination failure Methods Using sera from 106 infants who were born to HBV carrier mothers and failed in HB immunoprophylaxis, HBV S gene was amplified by PCR, transferred to nylon membranes for Southern blots, and then hybridized with oligonucleotide probes Eleven of non hybridizing samples were used for DNA sequencing Results 93 4% (99/106) of the samples were HBV DNA positive, and 30 3% (30/99) failed to hybridize with at least one of the four probes DNA sequencing confirmed that 10 of the 11 samples had an S gene mutation with amino acid (aa) change The identified mutants included nucleotide (nt) 546T→A(aa131N→T), nt531T→C (aa126I→T), nt491A→C (aa113T→P), nt491T→A (aa113S→T), nt533C→A (aa127P→T), nt581T→A (aa143S→T), nt636A→T (aa161Y→F), and nt679A→C (aa175L→F) The sequence in one mother infant pair was completely the same, with mutations at aa131 and aa161 Conclusions The prevalence of HBV surface mutants is about 30% in the children failing in HB vaccination HBV mutants can infect infants by maternal infant transmission

Expression of hMSH2 gene and mutant p53 in sporadic digestive tract tumors

Objective To investigate the role of mutated mismatch repair gene hMSH2 and mutant p53 gene in the carcinogenesis and development of sporadic digestive tract tumors. Methods hMSH2 gene in normal and tumor tissue of 30 digestive tract tumor specimens was examined using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) silver staining. The PCR product with an abnormal strand was sequenced directly. Mutant p53 protein in the tumor tissue was analyzed immunohistochemically. Results Six patients were identified as having mutated strands, three on hMSH2 exon 1 and three on hMSH2 exon 5. DNA sequencing revealed that all 6 patients had mutated basic groups that led to decrease in function of the hMSH2 protein. Forty percent (12/30) of patients were p53 positive. The frequency of mutated hMSH2 in p53 positive patients (41.7%) was significantly higher than in p53 negative patients (5.6%, P<0.05). Conclusion The mutation of hMSH2 plays an important role in the carcinogenesis and development of digestive tract tumors through stimulating p53 mutation.