Polymorphism and expression of GLUD1 in relation to reproductive performance in Jining Grey goats.

Abstract

Understanding the molecular mechanism of mammalian reproduction (puberty and prolificacy) will play a part in improving animal reproductive performance. GLUD1 (glutamate dehydrogenase 1) is important for mammalian reproduction, as shown in previous studies; however, its roles in puberty and prolificacy have rarely been reported. In this study, we designed seven pairs of primers (P1 to P7) for cloning and sequencing genomic DNA of Jining Grey goats and Liaoning Cashmere goats. Primer 8 (P8) was designed to detect single nucleotide polymorphism (SNP) of the GLUD1 in both sexually precocious and high-fecundity breeds (Jining Grey, Nanjiang Brown and Matou goats) and sexually late-maturing and low-fecundity breeds (Liaoning Cashmere, Inner Mongolia Cashmere and Taihang goats) by PCR-RFLP (restriction fragment length polymorphism). The real-time quantitative polymerase chain reaction (RT-qPCR) technique was used to detect the expression of GLUD1 in a variety of tissues. The results showed that the A197C mutation was only found in the amplification product of P6. For this SNP locus, only two genotypes (AA and AC) were detected in Nanjiang Brown goats, while three genotypes (AA, AC and CC) were detected in the other five breeds. In Jining Grey goats, the frequency of genotypes AA, AC and CC was 0.69, 0.26 and 0.05, respectively. In Jining Grey goats, AA genotype had 0.54 ($P<0.05$) and 0.3 ($P<0.05$) more kids than the CC and AC genotype, respectively, and no significant difference ($P>0.05$) was found in kidding number between the AC and CC genotype. GLUD1 was expressed in five tissues of different developmental stages. The expression level of GLUD1 in the hypothalamus was higher than that in the other four tissues except during puberty of Liaoning Cashmere goats. In puberty in goats, GLUD1 expression was significantly higher in ovaries than that in the juvenile period ($P<0.01$). RT-qPCR results showed that the expression of GLUD1 in ovaries may relate to the puberty of goats. The present study preliminarily indicated that there might be an association between the 197 locus of GLUD1 and sexual precocity in goats, and allele A of GLUD1 was a potential DNA marker for improving kidding number in Jining Grey goats.