Jiang Si-Wen, Jacobsson Lina, Kerje Susanne, Andersson Leif, Xiong Yuan-Zhu
Huazhong Agricultural University, Wuhan 430070, China.
Yi Chuan Xue Bao. 2002 Apr;29(4):322-5.
Genetic studies in mice have demonstrated a complementary role for the melanocortin-3 receptor (MC3R) and MC4R in the control of energy balance. Knockout of the MC3R in mice revealed an exclusively metabolic syndrome and increased fat mass. In the present study, we found a total of 5 novel single nucleotide polymorphisms (SNPs) of the MC3R gene in the chickens of high weight (HW) and low weight (LW) lines from divergently selected for high or low body weight at 8 weeks of age in White Plymouth Rock. Only one of the 5 SNPs led to amino acid substitution (Leu-->Arg) in HW and LW lines animals: a T/G substitution at nucleotide (nt) position 452 of coding sequence. Three of the 5 SNPs distinguished the birds from HW and LW lines: an A/G substitution at nt position 549 in LW line, an A/G substitution at nt position 882 in HW line, and a C/T substitution at nt position 894 in LW line, respectively. Another SNP was presented only in one of two HW line animals: a C/T substitution at nt position 564. Of the 5 SNPs, only A/G polymorphism at nt position 549 is located within a Dde I restriction enzyme recognition site. We designed a PCR-RFLP test based on the enzyme Dde I and screened the chickens for HW and LW lines' intercross. Analysis of variance revealed a significant influence of the MC3R genotype on body weight in the chickens for both sex and abdominal fat mass in male chickens. The result suggests that the MC3R as a candidate gene can explain significant difference for body weight in the intercross chickens.
小鼠的遗传学研究表明，黑皮质素-3受体（MC3R）和MC4R在能量平衡控制中具有互补作用。敲除小鼠体内的MC3R会导致单纯的代谢综合征以及脂肪量增加。在本研究中，我们在白来航鸡8周龄时体重经高低不同方向选育的高体重（HW）和低体重（LW）品系鸡中，共发现了MC3R基因的5个新的单核苷酸多态性（SNP）。这5个SNP中只有1个在HW和LW品系动物中导致了氨基酸替换（亮氨酸→精氨酸）：编码序列核苷酸（nt）位置452处的T/G替换。5个SNP中的3个能够区分HW和LW品系的鸡：LW品系中nt位置549处的A/G替换、HW品系中nt位置882处的A/G替换以及LW品系中nt位置894处的C/T替换。另一个SNP仅在两只HW品系动物中的一只中出现：nt位置564处的C/T替换。在这5个SNP中，只有nt位置549处的A/G多态性位于Dde I限制性内切酶识别位点内。我们基于Dde I酶设计了一项PCR-RFLP检测，并对HW和LW品系杂交后代的鸡进行了筛选。方差分析显示，MC3R基因型对雌雄鸡的体重以及雄鸡的腹部脂肪量均有显著影响。结果表明，MC3R作为一个候选基因可以解释杂交鸡体重的显著差异。
