Genetic polymorphism of the major histocompatibility complex （MHC） B-LBⅡ gene was studied by amplification of exon 2 using PCR, followed by cloning and DNA sequencing in eight indigenous Chinese chicken populations...Genetic polymorphism of the major histocompatibility complex （MHC） B-LBⅡ gene was studied by amplification of exon 2 using PCR, followed by cloning and DNA sequencing in eight indigenous Chinese chicken populations. To reveal the genetic variation of the B-LB Ⅱ gene, 37 types of patterns detected by PCR-SSCP were investigated first, which would be used to screen novel B-LB Ⅱsequences within the breeds. The types of PCR-SSCP patterns and final sequencing allowed for the identification of 31 novel MHC B-LBⅡ alleles from 30 unrelated individuals of Chinese chickens that were sampled. These are the first designators for the alleles of chicken MHC B-LBⅡ gene based on the rule of assignment for novel mammalian alleles. Sequence alignment of the 31 B-LB Ⅱ alleles revealed a total of 68 variable sites in the fragment of exon 2, of which 51 parsimony informative and 17 singleton variable sites were observed. Among the polymorphic sites, the nucleotide substitutions in the first and second positions of the codons accounted for 36.76% and 35.29%, respectively. The sequence similarities between the alleles were estimated to be 90.6%-99.5%. The relative frequencies of synonymous and nonsynonymous nucleotide substitutions within the region were 2.92%±0.94% and 14.64%±2.67%, respectively. These results indicated that the genetic variation within exon 2 appeared to have largely arisen by gene recombination and balancing selection. Alignment of the deduced amino acid sequences of the β1 domain coded by exon 2 revealed 6 synonymous mutations and 27 nonsynonymous substitutions at the 33 disparate sites. In particular, the nonsynonymous substitutions at the putative peptide-binding sites are considered to be associated with immunological specificity of MHC B-LB Ⅱ molecule in Chinese native chickens. These results can provide a molecular biological basis for the study of disease resistance in chicken breeding.展开更多
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
Objective:To investigate whether angiotensinⅡtype 1 receptor(AGTR1 A1166C)gene polymorphism was associated with the effectiveness of valsartan monotherapy in Chinese patients with essential hypertension.Methods:This ...Objective:To investigate whether angiotensinⅡtype 1 receptor(AGTR1 A1166C)gene polymorphism was associated with the effectiveness of valsartan monotherapy in Chinese patients with essential hypertension.Methods:This retrospective analysis included 198 patients(≥18 years of age)who received valsartan monotherapy(80 mg/day)for newly developed essential hypertension at the authors’center between January 1,2020 and December 31,2023.Genotyping for AGTR1 A1166C gene polymorphism was done by polymerase chain reaction(PCR)-melting curve analysis of genomic DNA from peripheral blood samples.A dominant genetic model for AGTR1 A1166C(AA genotype versus AC+CC genotype)was used.Multivariate regression analysis of baseline variables and AGTR1 polymorphism was conducted to identify predictors of target blood pressure attainment(<140/90 mmHg)at the 4-week follow-up.Results:The median age of the 198 patients was(53.7±13.5)years,and 58%were men.Genotyping assays showed that 164 patients had the AA genotype,and 34 patients were of the AC/CC genotype,including 30 with the AC genotype and 4 with the CC genotype.Allele distribution was consistent with Hardy Weinberg equilibrium.109 Patients(55.1%)attained the blood pressure target.Multivariate analysis showed that smoking(versus no smoking,HR 0.314,95%CI 0.159-0.619,P=0.001)and AGTR1 A1166C AA genotype(versus AC/CC,HR 2.927,95%CI 1.296-6.611,P=0.023)were significant and independent predictors of target attainment.25 Patients(73.5%)with AGTR1 A1166C AC/CC genotype attained the target versus 51.2%(51/164)of patients with AGTR1 A1166C AA genotype(P=0.017).Patients with AGTR1 A1166C AC/CC genotype had a significantly greater reduction in systolic blood pressure[(33.1±10.8)mmHg versus(29.2±11.7)mmHg in AA carriers;(P=0.029)].Conclusions:Hypertensive patients carrying one or two C alleles of the AGTR1 A1166C gene were more responsive to valsartan treatment.展开更多
基金This work was supported by "948" Project of China (No. 2001-361), Chinese National Programs for High Technology Research and Development (No. 2004AA222170), and Key Project of Chinese National Programs for Fundamental Research and Develop-ment (No. G2000016103).
文摘Genetic polymorphism of the major histocompatibility complex （MHC） B-LBⅡ gene was studied by amplification of exon 2 using PCR, followed by cloning and DNA sequencing in eight indigenous Chinese chicken populations. To reveal the genetic variation of the B-LB Ⅱ gene, 37 types of patterns detected by PCR-SSCP were investigated first, which would be used to screen novel B-LB Ⅱsequences within the breeds. The types of PCR-SSCP patterns and final sequencing allowed for the identification of 31 novel MHC B-LBⅡ alleles from 30 unrelated individuals of Chinese chickens that were sampled. These are the first designators for the alleles of chicken MHC B-LBⅡ gene based on the rule of assignment for novel mammalian alleles. Sequence alignment of the 31 B-LB Ⅱ alleles revealed a total of 68 variable sites in the fragment of exon 2, of which 51 parsimony informative and 17 singleton variable sites were observed. Among the polymorphic sites, the nucleotide substitutions in the first and second positions of the codons accounted for 36.76% and 35.29%, respectively. The sequence similarities between the alleles were estimated to be 90.6%-99.5%. The relative frequencies of synonymous and nonsynonymous nucleotide substitutions within the region were 2.92%±0.94% and 14.64%±2.67%, respectively. These results indicated that the genetic variation within exon 2 appeared to have largely arisen by gene recombination and balancing selection. Alignment of the deduced amino acid sequences of the β1 domain coded by exon 2 revealed 6 synonymous mutations and 27 nonsynonymous substitutions at the 33 disparate sites. In particular, the nonsynonymous substitutions at the putative peptide-binding sites are considered to be associated with immunological specificity of MHC B-LB Ⅱ molecule in Chinese native chickens. These results can provide a molecular biological basis for the study of disease resistance in chicken breeding.
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.
基金Science and Technology Key Project of Xuzhou Municipal Health Commission,Jiangsu Province,China(XWKYHT20210531)Pengcheng Yingcai-Medical Young Reserve Talent Programme(XWRCHT20220013).
文摘Objective:To investigate whether angiotensinⅡtype 1 receptor(AGTR1 A1166C)gene polymorphism was associated with the effectiveness of valsartan monotherapy in Chinese patients with essential hypertension.Methods:This retrospective analysis included 198 patients(≥18 years of age)who received valsartan monotherapy(80 mg/day)for newly developed essential hypertension at the authors’center between January 1,2020 and December 31,2023.Genotyping for AGTR1 A1166C gene polymorphism was done by polymerase chain reaction(PCR)-melting curve analysis of genomic DNA from peripheral blood samples.A dominant genetic model for AGTR1 A1166C(AA genotype versus AC+CC genotype)was used.Multivariate regression analysis of baseline variables and AGTR1 polymorphism was conducted to identify predictors of target blood pressure attainment(<140/90 mmHg)at the 4-week follow-up.Results:The median age of the 198 patients was(53.7±13.5)years,and 58%were men.Genotyping assays showed that 164 patients had the AA genotype,and 34 patients were of the AC/CC genotype,including 30 with the AC genotype and 4 with the CC genotype.Allele distribution was consistent with Hardy Weinberg equilibrium.109 Patients(55.1%)attained the blood pressure target.Multivariate analysis showed that smoking(versus no smoking,HR 0.314,95%CI 0.159-0.619,P=0.001)and AGTR1 A1166C AA genotype(versus AC/CC,HR 2.927,95%CI 1.296-6.611,P=0.023)were significant and independent predictors of target attainment.25 Patients(73.5%)with AGTR1 A1166C AC/CC genotype attained the target versus 51.2%(51/164)of patients with AGTR1 A1166C AA genotype(P=0.017).Patients with AGTR1 A1166C AC/CC genotype had a significantly greater reduction in systolic blood pressure[(33.1±10.8)mmHg versus(29.2±11.7)mmHg in AA carriers;(P=0.029)].Conclusions:Hypertensive patients carrying one or two C alleles of the AGTR1 A1166C gene were more responsive to valsartan treatment.
