Liu Z, Shi Z D, Liu Y, Li M Y, Huang Y M, Yao B H
Department of Animal Science, South China Agricultural University, Guangzhou 510642, China.
Gen Comp Endocrinol. 2008 Jan 1;155(1):208-16. doi: 10.1016/j.ygcen.2007.04.017. Epub 2007 May 1.
In studying the roles of prolactin in regulation of seasonal reproduction, incubation, broodiness and laying performance in goose, the goose PRL gene was cloned in Magang goose. The goose PRL cDNA shared 98.4%, 92.2%, 92%, and 91.9% sequence homology to duck, turkey, chicken and quail PRLs, respectively. The goose PRL gene consisted of 5 exons and 4 introns, just as in other species. The 5' proximal regulatory region shared high homology with those in other avian species as well, and, apart from other non-specific transcription factor binding sites, contained 2 regulatory element binding sites, a Pit-1 (-130/-122) and a VIP response element (-64/-53). The deduced 199-residue mature goose PRL shared 98.5%, 94%, 93%, and 92% homology to duck, quail, chicken, and turkey PRLs, respectively. When compared with other vertebrates, all residues were found to be highly conserved at the key positions in the 4 conserved domains (PD1-PD4), including the 6 cysteine residues at positions 4, 11, 58, 175, 191, and 199. The only exception was a substitution of Arginine by Histidine at position 176 in the mature PRL peptide. These findings render goose PRL as having a similar hydropathy profile and similar secondary and tertiary structures with other PRLs. Goose PRL also possesses an N-linked glycosylation site (Asn-X-Ser), at position 6, and an alternative glycosylation site (Asn-Gly-Cys), at position 56. Five PRL isoforms were detected in goose, as well as in chicken pituitary glands, by immunoblotting analysis. Results of this study not only provided a starting point for further study of PRL function, synthesis, and secretion in goose species, but also for breeding new goose lines efficiently using the genomic information.
在研究催乳素在鹅的季节性繁殖、孵化、抱窝及产蛋性能调节中的作用时，马岗鹅的催乳素基因（PRL基因）被克隆。鹅PRL cDNA与鸭、火鸡、鸡和鹌鹑的PRL分别具有98.4%、92.2%、92%和91.9%的序列同源性。鹅PRL基因与其他物种一样，由5个外显子和4个内含子组成。其5'近端调控区与其他鸟类物种的调控区也具有高度同源性，除了其他非特异性转录因子结合位点外，还包含2个调控元件结合位点，一个Pit-1（-130/-122）和一个VIP反应元件（-64/-53）。推导的199个氨基酸残基的成熟鹅PRL与鸭、鹌鹑、鸡和火鸡的PRL分别具有98.5%、94%、93%和92%的同源性。与其他脊椎动物相比，在4个保守结构域（PD1-PD4）的关键位置上，所有氨基酸残基都高度保守，包括第4、11、58、175、191和199位的6个半胱氨酸残基。唯一的例外是成熟PRL肽中第176位的精氨酸被组氨酸取代。这些发现表明鹅PRL与其他PRL具有相似的亲水性图谱以及相似的二级和三级结构。鹅PRL在第6位还具有一个N-连接糖基化位点（Asn-X-Ser），在第56位具有一个可变糖基化位点（Asn-Gly-Cys）。通过免疫印迹分析在鹅以及鸡的垂体中检测到了5种PRL同工型。本研究结果不仅为进一步研究鹅PRL的功能、合成和分泌提供了起点，也为利用基因组信息高效培育新的鹅品系提供了依据。
