Qiu Xuemei

The single nucleotide polymorphisms of chicken melanocortin-4 receptor (MC4R) gene and their association analysis with carcass traits

Mutations of the melanocortin-4 receptor (MC4R) gene are associated with the appetite, obesity and growth in pig, mice and human. But little is known about the function of chicken MC4R gene. In this study, F2 chicken resource population derived from broilers crossing to Silky was screened for the polymorphisms of the MC4R gene using PCR-single strand conformation polymorphism (PCR-SSCP) and DNA sequencing methods. Four single nucleotide polymorphisms (SNPs) sites were found. The mutation (C→T) in the 5′ regulation region of chicken MC4R gene results in one more NF-E2 and cap transcription factor binding sites in the mutation allele than in the wild allele. One missense mutation (G→A) occurs in the coding region (61nt), which changes the glycine to arginine. Moreover, in the coding region there are 2 synonymous mutations, one G→T mutation at 315nt and one C→T mutation at 336nt. Least square analysis of the SNPs and carcass traits showed that BB, DD and FF genotypes are significantly associated with body weight, carcass weight (or half carcass weight), and leg muscle weight (P<0.05 or P<0.01). But no significant association between the genotypes and abdominal fat weight is found. The results present the evidence that the chicken MC4R gene can be selected as the major candidate gene for the carcass traits such as body weight and growth.

红鳍东方鲀（ Takifugu rubripes ）干扰素调节因子2基因的克隆及原核表达

干扰素调节因子（Interferon regulatory factor,IRF）是一种多功能的转录因子。采用反转录聚合酶链式反应（RT-PCR）和c DNA末端快速扩增（RACE）技术克隆了红鳍东方鲀干扰素调节因子2（Interferon regulatory factor 2,IRF2）基因的全长c DNA。该基因全长为1 552 bp,其中5＇非编码区（5＇-UTR）187 bp,3＇非编码区（3＇-UTR）429 bp,编码区（CDS）为936 bp,共编码311个氨基酸。将IRF2的编码区序列连接到原核表达载体p ET32a（＋）,成功构建了重组体p ET32a（＋）-IRF2。将重组体p ET32a（＋）-IRF2转入大肠杆菌感受态细胞BL21（DE3）中,获得了重组表达IRF2的基因工程菌。经IPTG诱导,p ET32a（＋）-IRF2在BL21中得到了融合表达。通过对表达产物的纯化和Western blotting检测,结果显示红鳍东方鲀IRF2基因在大肠杆菌中的表达效果较高,目的蛋白准确。

红鳍东方鲀转录因子 GATA4 基因的表达

利用荧光实时定量PCR（qRT-PCR）技术对红鳍东方鲀（Takifugu rubripes）成鱼的肾脏、肌肉、脑、脾脏、肝脏、精巢和卵巢等组织进行了GATA4 基因的表达分析，并对幼鱼不同发育时间的个体水平上的GATA4 基因的表达进行分析。结果显示，红鳍东方鲀成鱼的肌肉、脾脏、肾脏和脑等4 个组织中的GATA4 的表达量差异不显著，精巢、卵巢和肝脏的GATA4 的表达量显著高于其他组织（P<0.05），GATA4 在精巢、肝脏中的表达量显著高于卵巢中（P<0.05）。在雄性幼鱼5 个发育时期中（23、30、40、60 和80 日龄），GATA4 的表达量从23 日龄到30 日龄逐渐升高，30 日龄最高且明显高于同时期雌鱼GATA4 的表达量（P<0.01），随后到40 日龄之间表达量逐渐降低，从60 日龄到80 日龄又有上升的趋势。在雌性幼鱼5 个发育时期中，GATA4 表达量从23 日龄到40 日龄逐渐升高，40 日龄最高且明显高于同时期雄鱼GATA4 的表达量（P<0.01），到60 日龄期间表达量降低，从80 日龄后又有上升趋势。各时期雌雄幼鱼，除40 日龄外，其他各个时期在雄性中GATA4 的表达量均高于在雌性中的表达量。