Polymorphisms in the 5′ flanking region of the insulin-like growth factor I gene are associated with growth traits in largemouth bass Micropterus salmoides
Polymorphisms in the 5′ flanking region of the insulin-like growth factor I gene are associated with growth traits in largemouth bass Micropterus salmoides
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DOI：
10.1007/s12562-008-0051-3
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发表时间：
2009-04-01
影响因子：
1.9
通讯作者：
Yu, Ling Yun
中科院分区：
文献类型：
--
作者：
Li, Xiao Hui;Bai, Jun Jie;Yu, Ling Yun
胰岛素样生长因子I（IGF-1）在鱼类生长发育中起重要作用。由于IGF-I的启动子调节IGF-I的表达，启动子区的多态性可能对IGF-I表达和功能的差异具有重要的功能。本研究克隆了大口黑鲈IGF-Ⅰ基因5 '侧翼区（1，770 bp），并对其进行了序列测定和分析。几个推定的肝脏富集的转录因子结合位点，包括HNF-1 α，HNF-3 β和C/EBP，被发现在大口黑鲈IGF-I基因的启动子序列中有多个拷贝。它不包含共有TATA、CCAAT样或GAGA序列。对来自个体鱼的5 '侧翼序列的测序显示存在一个缺失（GTTT）和两个单核苷酸取代，导致两种不同的单倍型：ATTTTTGTTTTT（A）和ATAATT-TT（B）。单倍型进行了测试，其与生长性状的人口91大口黑鲈个人使用聚合酶链反应。使用一般线性模型进行关联分析。结果表明，单倍型对体重和体宽有显著影响（P <0.05）。AA基因型个体的体重和体宽显著高于AB和BB基因型个体（P <0.05）。此外，通过使用半定量RT-PCR方法评估基因型对肝脏中IGF-I mRNA表达的影响。结果表明，启动子区基因多态性对IGF-ImRNA表达量有显著影响（P <0.01），AA基因型的IGF-ImRNA表达量显著高于AB和BB基因型（P <0.05和P <0.01）。我们的研究结果表明，IGF-I基因可能是一个潜在的数量性状核苷酸，影响生长性状的大口黑鲈。
Insulin-like growth factor I (IGF-1) plays an important role in fish growth and development. As the promoter of IGF-I regulates the expression of IGF-I, polymorphisms in the promoter region could be functionally important to differences in IGF-I expression and function. In this study, the 5' flanking region (1,770 bp) of the largemouth bass IGF-I gene was cloned, sequenced and characterized. Several putative liver-enriched transcriptional factor binding sites, including HNF-1 alpha, HNF-3 beta and C/EBP, were found to have multiple copies in the promoter sequence of the largemouth bass IGF-I gene. It did not contain consensus TATA, CCAAT-like or GAGA sequences. Sequencing of 5' flanking sequences from individual fish revealed the presence of a deletion (GTTT) and two single-nucleotide substitutions, causing two different haplotypes: ATTTTTGTTTTT(A) and ATAATT-TT(B). The haplotypes were tested for their association with growth traits in a population of 91 largemouth bass individuals using polymerase chain reaction. The association analysis was carried out using a general linear model. Results showed the haplotypes had significant effects on body weight and body width (P < 0.05). The individuals with the AA genotype had significantly higher body weight and body width than those with the AB and BB genotypes (P < 0.05). Moreover, the effect of the genotypes on IGF-I mRNA expression in the liver was evaluated through the use of a semiquantitative RT-PCR method. The results showed that the IGF-I mRNA expression levels were affected by the promoter polymorphisms (P < 0.01), and that levels of IGF-I mRNA of the AA genotype in liver were greater than those of both the AB and the BB genotypes (P < 0.05 and P < 0.01). Our results implied that the IGF-I gene could be a potential quantitative trait nucleotide that affects growth traits in largemouth bass.