Wu Haizhen, Fan Fangtao, Liang Caizhi, Zhou Yan, Qiao Xibo, Sun Y, Jiang Yunliang, Kang Li
Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Taian, 271018, China.
Institute of Poultry Science, Academy of Agricultural Sciences of Shandong Province, Jinan, 250023, China.
Anim Reprod Sci. 2019 Feb;201:93-101. doi: 10.1016/j.anireprosci.2019.01.002. Epub 2019 Jan 3.
MicroRNAs (miRNAs) are a class of endogenous non-coding RNAs that have an important role in post-transcriptional regulation. Previous analysis of the chicken ovary transcriptome indicated there was a differential abundance of miR-26a-5p in sexually mature and immature hens. In this study, ten single nucleotide polymorphism (SNP) sites in miR-26a-5p primary transcripts (pri-miR-26a-5p) were identified using Sanger sequencing on PCR products in three chicken breeds, among which, the rs316365438(C > T)SNP was associated with age at first egg (AFE) and total number of eggs at 32 weeks (E32). The hens with the TT genotype of the rs316365438(C > T)SNP had an earlier AFE and greater E32 than those with CC and CT genotypes. Due to the presence of linkage disequilibrium (LD) in SNPs, there were only two dominant haplotypes. The two dominant haplotypes with different free-energy and secondary structure were identified and the overexpression vectors were constructed. Overexpression of mature miR-26a-5p from TCTACGCACG haplotype was greater than that from the TTTATATACA haplotype. In summary, the polymorphisms of pri-miR-26a-5p are associated with chicken egg production traits and affect the transcript abundance of the mature miR-26a-5p.
微小RNA（miRNA）是一类内源性非编码RNA，在转录后调控中发挥重要作用。先前对鸡卵巢转录组的分析表明，性成熟和未成熟母鸡中miR-26a-5p的丰度存在差异。在本研究中，通过对三个鸡品种的PCR产物进行桑格测序，在miR-26a-5p初级转录本（pri-miR-26a-5p）中鉴定出10个单核苷酸多态性（SNP）位点，其中rs316365438（C>T）SNP与开产日龄（AFE）和32周龄时的总产蛋数（E32）相关。rs316365438（C>T）SNP的TT基因型母鸡比CC和CT基因型母鸡具有更早的AFE和更多的E32。由于SNP中存在连锁不平衡（LD），仅有两种主要单倍型。鉴定出具有不同自由能和二级结构的两种主要单倍型，并构建了过表达载体。来自TCTACGCACG单倍型的成熟miR-26a-5p过表达量高于TTTATATACA单倍型。总之，pri-miR-26a-5p的多态性与鸡的产蛋性状相关，并影响成熟miR-26a-5p的转录丰度。
