Expression Analysis of the Prolific Candidate Genes, BMPR1B, BMP15, and GDF9 in Small Tail Han Ewes with Three Fecundity (FecB Gene) Genotypes

Abstract

The expression characteristics of the prolific candidate genes, <i>BMPR1B</i>, <i>BMP15</i>, and <i>GDF9</i>, in the major visceral organs and hypothalamic⁻pituitary⁻gonadal (HPG) axis tissues of three <i>FecB</i> genotypes (FecB BB, FecB B+, and FecB ++) were explored in STH ewes using RT-PCR and qPCR. The results were as follows, <i>BMPR1B</i> was expressed in all FecB BB genotype (Han BB) tissues, and <i>GDF9</i> was expressed in all selected tissues, but <i>BMP15</i> was specifically expressed in the ovaries. Further study of ovarian expression indicated that there was no difference in <i>BMPR1B</i> expression between genotypes, but the FecB B+ genotype (Han B+) had greater expression of <i>GDF9</i> and <i>BMP15</i> than Han BB and FecB ++ genotype (Han ++) (<i>p</i> < 0.05, <i>p</i> < 0.01). <i>BMP15</i> expression was lower in the ovaries of Han BB than in Han ++ sheep, but the reverse was shown for <i>GDF9</i>. The gene expression in non-ovarian tissues was also different between genotypes. Therefore, we consider that the three genes have an important function in ovine follicular development and maturation. This is the first systematic analysis of the tissue expression pattern of <i>BMPR1B</i>, <i>BMP15,</i> and <i>GDF9</i> genes in STH sheep of the three <i>FecB</i> genotypes. These results contribute to the understanding of the molecular regulatory mechanism for ovine reproduction.