The worldwide declines in amphibian populations have largely been caused by infectious fungi and bacteria. Given that vertebrate immunity against these extracellular pathogens is primarily functioned by the major hist...The worldwide declines in amphibian populations have largely been caused by infectious fungi and bacteria. Given that vertebrate immunity against these extracellular pathogens is primarily functioned by the major histocompatibility complex（MHC） class Ⅱ molecules, the characterization and the evolution of amphibian MHC class Ⅱ genes have attracted increasing attention. The polymorphism of MHC class Ⅱ genes was found to be correlated with susceptibility to fungal pathogens in many amphibian species, suggesting the importance of studies on MHC class Ⅱ genes for amphibians. However, such studies on MHC class Ⅱ gene evolution have rarely been conducted on amphibians in China. In this study, we chose Omei treefrog（Rhacophorus omeimontis）, which lived moist environments easy for breeding bacteria, to study the polymorphism of its MHC class Ⅱ genes and the underlying evolutionary mechanisms. We amplified the entire MHC class ⅡB exon 2 sequence in the R. omeimontis using newly designed primers. We detected 102 putative alleles in 146 individuals. The number of alleles per individual ranged from one to seven, indicating that there are at least four loci containing MHC class ⅡB genes in R. omeimontis. The allelic polymorphism estimated from the 102 alleles in R. omeimontis was not high compared to that estimated in other anuran species. No significant gene recombination was detected in the 102 MHC class ⅡB exon 2 sequences. In contrast, both gene duplication and balancing selection greatly contributed to the variability in MHC class ⅡB exon 2 sequences of R. omeimontis. This study lays the groundwork for the future researches to comprehensively analyze the evolution of amphibian MHC genes and to assess the role of MHC gene polymorphisms in resistance against extracellular pathogens for amphibians in China.展开更多
To elucidate the structure of SLA-3 alleles on inbred line of Wuzhishan pig （WZSP） population, we examined the partial exon 1, completed exon 2, and partial exon 3 of SLA-3 loci using the reverse transcription-polym...To elucidate the structure of SLA-3 alleles on inbred line of Wuzhishan pig （WZSP） population, we examined the partial exon 1, completed exon 2, and partial exon 3 of SLA-3 loci using the reverse transcription-polymerase chain reaction （RT- PCR） and the sequencing-based method in 32 WZSPs. According to pedigree and amplification results, PCR products of 8 WZSPs were selected to clone and sequence. Nine different nucleotide sequences were obtained. After comparing the DNA and protein sequences of the WZSPs SLA-3 alleles with the published GenBank SLA sequences, it was found that the SLA-3 alleles in WZSPs were all novel, but there were very few variations among them. Comparision of SLA-3 and HLA-A protein sequences indicated that there was more sequence homology. Meanwhile, the construction of a phylogenetic tree using the nucleotide sequences of 23 SLA-3 alleles and 1 HLA-A allele represented that the WZSP population owns its unique genetics resource. In this study, the alleles of SLA-3 on WZSP group were successfully detected and analyzed, which provided the firm basis on the genotype of SLA-3 for breeding specific haplotypes WZSPs.展开更多
AIM: To investigate the relationship between the polymorphism of class Ⅱ transactivator (CIITA) gene promoters and chronic hepatitis B (CHB). METHODS: Genomic DNA was prepared from peripheral blood leukocytes. Promot...AIM: To investigate the relationship between the polymorphism of class Ⅱ transactivator (CIITA) gene promoters and chronic hepatitis B (CHB). METHODS: Genomic DNA was prepared from peripheral blood leukocytes. Promoters Ⅰ,Ⅲ and Ⅳ of gene were analyzed respectively with polymerase chain reaction single strand conformation polymorphism (PCR-SSCP) in 65 patients with CHB, 26 patients with acute hepatitis B (AHB) and 85 normal controls. RESULTS: No abnormal migration was found in PCR-SSCP analysis of the three promoters in the three groups. Also, no sequential difference was observed at the three promoters among the CHB patients, AHB patients and normal controls. CONCLUSION: No polymorphism in promoters I, III and IV of CIITA gene exists in CHB patients, ABH patients and normal controls, suggesting that the promoter of CIITA gene might be a conserved domain.展开更多
基金supported by the National Natural Science Foundation of China(No.31201713,No.31270425 and No.31470442)
文摘The worldwide declines in amphibian populations have largely been caused by infectious fungi and bacteria. Given that vertebrate immunity against these extracellular pathogens is primarily functioned by the major histocompatibility complex（MHC） class Ⅱ molecules, the characterization and the evolution of amphibian MHC class Ⅱ genes have attracted increasing attention. The polymorphism of MHC class Ⅱ genes was found to be correlated with susceptibility to fungal pathogens in many amphibian species, suggesting the importance of studies on MHC class Ⅱ genes for amphibians. However, such studies on MHC class Ⅱ gene evolution have rarely been conducted on amphibians in China. In this study, we chose Omei treefrog（Rhacophorus omeimontis）, which lived moist environments easy for breeding bacteria, to study the polymorphism of its MHC class Ⅱ genes and the underlying evolutionary mechanisms. We amplified the entire MHC class ⅡB exon 2 sequence in the R. omeimontis using newly designed primers. We detected 102 putative alleles in 146 individuals. The number of alleles per individual ranged from one to seven, indicating that there are at least four loci containing MHC class ⅡB genes in R. omeimontis. The allelic polymorphism estimated from the 102 alleles in R. omeimontis was not high compared to that estimated in other anuran species. No significant gene recombination was detected in the 102 MHC class ⅡB exon 2 sequences. In contrast, both gene duplication and balancing selection greatly contributed to the variability in MHC class ⅡB exon 2 sequences of R. omeimontis. This study lays the groundwork for the future researches to comprehensively analyze the evolution of amphibian MHC genes and to assess the role of MHC gene polymorphisms in resistance against extracellular pathogens for amphibians in China.
文摘To elucidate the structure of SLA-3 alleles on inbred line of Wuzhishan pig （WZSP） population, we examined the partial exon 1, completed exon 2, and partial exon 3 of SLA-3 loci using the reverse transcription-polymerase chain reaction （RT- PCR） and the sequencing-based method in 32 WZSPs. According to pedigree and amplification results, PCR products of 8 WZSPs were selected to clone and sequence. Nine different nucleotide sequences were obtained. After comparing the DNA and protein sequences of the WZSPs SLA-3 alleles with the published GenBank SLA sequences, it was found that the SLA-3 alleles in WZSPs were all novel, but there were very few variations among them. Comparision of SLA-3 and HLA-A protein sequences indicated that there was more sequence homology. Meanwhile, the construction of a phylogenetic tree using the nucleotide sequences of 23 SLA-3 alleles and 1 HLA-A allele represented that the WZSP population owns its unique genetics resource. In this study, the alleles of SLA-3 on WZSP group were successfully detected and analyzed, which provided the firm basis on the genotype of SLA-3 for breeding specific haplotypes WZSPs.
基金Supported by the National Natural Science Foundation of China,No. 30270597
文摘AIM: To investigate the relationship between the polymorphism of class Ⅱ transactivator (CIITA) gene promoters and chronic hepatitis B (CHB). METHODS: Genomic DNA was prepared from peripheral blood leukocytes. Promoters Ⅰ,Ⅲ and Ⅳ of gene were analyzed respectively with polymerase chain reaction single strand conformation polymorphism (PCR-SSCP) in 65 patients with CHB, 26 patients with acute hepatitis B (AHB) and 85 normal controls. RESULTS: No abnormal migration was found in PCR-SSCP analysis of the three promoters in the three groups. Also, no sequential difference was observed at the three promoters among the CHB patients, AHB patients and normal controls. CONCLUSION: No polymorphism in promoters I, III and IV of CIITA gene exists in CHB patients, ABH patients and normal controls, suggesting that the promoter of CIITA gene might be a conserved domain.
