Association of a missense mutation in the bovine leptin gene with carcass fat content and leptin mRNA levels
Association of a missense mutation in the bovine leptin gene with carcass fat content and leptin mRNA levels
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DOI：
10.1051/gse:2001006
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发表时间：
2002-01-01
影响因子：
4.1
通讯作者：
Schmutz, SM
中科院分区：
文献类型：
--
作者：
Buchanan, FC;Fitzsimmons, CJ;Schmutz, SM
此前，我们已经证明，位于牛瘦素基因下游3.6kb的BM1500微卫星的等位基因与154头无关的肉牛的屠体脂肪测量有关。随后，在瘦素基因的外显子2中发现了胞嘧啶(C)到胸腺嘧啶(T)的转换，该转换编码了精氨酸到半胱氨酸的氨基酸变化。设计了一种聚合酶链式反应-限制性片段长度多态性方法，对4个肉牛品种的等位基因频率与屠体脂肪水平进行了相关分析。T等位基因与较肥的屠体相关，C等位基因与较瘦的屠体相关。品种间SNP等位基因频率显示，英国品种T等位基因频率较高，而大陆品种C等位基因频率较高。建立了一种核糖核酸酶保护试验，以定量检测按基因选择的另一组动物的瘦素mRNA。胸腺嘧啶纯合子的动物表达更高水平的瘦素mRNA。这可能表明T等位基因给蛋白质增加了额外的半胱氨酸，导致生物功能的部分丧失，因此可能是致病突变。
Previously, we have shown that alleles of the BM1500 microsatellite, located 3.6 kb downstream of the leptin gene in cattle, were associated with carcass fat measures in a population of 154 unrelated beef bulls. Subsequently, a cytosine (C) to thymine (T) transition that encoded an amino acid change of an arginine to a cysteine was identified in exon 2 of the leptin gene. A PCR-RFLP was designed and allele frequencies in four beef breeds were correlated with levels of carcass fat. The T allele was associated with fatter carcasses and the C allele with leaner carcasses. The frequencies of the SNP alleles among breeds indicated that British breeds have a higher frequency of the T allele whereas the continental breeds have a higher occurrence of the C allele. A ribonuclease protection assay was developed to quantify leptin mRNA in a separate group of animals selected by genotype. Animals homozygous for thymine expressed higher levels of leptin mRNA. This may suggest that the T allele, which adds an extra cysteine to the protein, imparts a partial loss of biological function and hence could be the causative mutation.