ABSTRACT

1. Ovalbumin (SERPINB14) is the most abundant protein present in egg white contributing about 54% of the total egg protein. In this study, the objectives were to clone and characterise the coding sequence of the SERPINB14 gene, to explore its expression profile, identify polymorphisms in the promoter of the gene and explore any association with egg quality traits in White Leghorn chickens.

2. SNPs and mRNA expression of SERPINB14 in White Leghorn chicken lines were detected by PCR-single strand conformation polymorphism (SSCP) along with sequencing and qPCR. The open reading frame (ORF) was cloned in an expression plasmid vector and sequenced.

3. The ORF of this gene was 1161 bp encoding a peptide of 386 amino acids. There were three SNPs observed in the coding region of the gene, one of which was of the mis-sense type, having c562G>A transition which resulted in substitution of alanine to threonine at position 188 in the protein sequence. In both the lines, an increase in expression of the gene was observed after onset of egg production with peak expression at the 40^th week of age compared to before onset of lay. The SERPINB14 gene was expressed in the magnum, but not in ovary and infundibulum, tissues of each White Leghorn line. The promoter region of the gene showed SNPs with three haplotypes; H1, H2, and H3. The haplo groups were associated with the egg weight and age at sexual maturity in the IWI line and Haugh unit and albumin index in the IWK line.

4. It was concluded that the ORF of SERPINB14 gene in White Leghorn chicken lines is polymorphic. The promoter region of the gene is also polymorphic and has significant (P < 0.05) association with Haugh unit and egg weight in IWK and IWI chicken lines, respectively.

摘要

1. 卵清蛋白 (SERPINB14) 是蛋清中含量最丰富的蛋白质，约占总蛋蛋白的 54%。在这项研究中，目标是克隆和表征SERPINB14基因的编码序列，探索其表达谱，鉴定该基因启动子中的多态性，并探索与白来亨鸡蛋品质性状的任何关联。

2.采用PCR-单链构象多态性(SSCP)结合测序和qPCR检测白来亨鸡系SERPINB14的SNP和mRNA表达。将开放阅读框（ORF）克隆到表达质粒载体中并测序。

3.该基因的ORF为1161 bp，编码386个氨基酸的肽段。在该基因的编码区观察到三个SNP，其中一个是错义类型，具有c562G> A转换，导致蛋白质序列中188位的丙氨酸取代为苏氨酸。在这两个品系中，与产蛋开始前相比，在产蛋开始后观察到基因表达增加，在第 40 周时达到峰值^表达。SERPINB14 _基因在每个 White Leghorn 品系的大部表达，但不在卵巢和漏斗部组织中表达。该基因的启动子区域显示出具有三种单倍型的SNP；H1、H2 和 H3。单倍群与 IWI 系中的卵重和性成熟年龄以及 IWK 系中的 Haugh 单位和白蛋白指数相关。

4、得出结论，白来亨鸡系SERPINB14基因的开放阅读框是多态性的。该基因的启动子区域也是多态性的，并且分别与IWK和IWI鸡系中的Haugh单位和蛋重具有显着（P <0.05）相关性。