Cloning and Expression Analysis of HAT1 and HDAC1 in the Testes of Mature Yaks and Their Sterile Hybrids.

Abstract

Simple SummaryCattle-yak is the hybrid between male cattle (Bos taurus) and female yak (Bos grunniens). Male cattle-yak can not produce normal sperm. The mechanisms that underlie cattle-yak male sterility have not been elucidated. Histone acetylation is a common regulation mode that plays an important role in the development of gametes. The objective of this study was to explore the molecular mechanism of male sterility in yak hybrids based on histone acetyltransferase 1 (HAT1) and histone deacetylase 1 (HDAC1), two enzymes that regulate histone acetylation. The mRNA and protein expression levels of HAT1 in the testes of adult cattle-yaks were significantly lower than in adult yaks, and the protein expression levels of HDAC1 were significantly higher than in yaks. In addition, H3K9 acetylation levels in cattle-yak testes were significantly lower than in yaks. These results suggest that male sterility in cattle-yaks might be associated with decreased histone acetylation levels in the testes.The objective of this study was to explore the molecular mechanism of male sterility in yak hybrids based on HAT1 and HDAC1. Total RNA was extracted from the testes of adult yaks (n = 11) and sterile cattle-yaks (n = 11) followed by reverse transcription. The coding sequence (CDS) of yak HAT1 and HDAC1 were obtained by conventional polymerase chain reaction (PCR) and gene cloning. The testicular mRNA and protein levels of HAT1 and HDAC1 in yaks and cattle-yaks were detected by quantitative PCR (qPCR) and Western blotting, respectively, and the histone H3 lysine 9 (H3K9) histone acetylation level in the testes of yaks and cattle-yaks was assayed using enzyme linked immunosorbent assay (ELISA). The results showed that the CDS of HAT1 and HDAC1 were 1242 bp and 1449 bp in length, encoding 413 and 482 amino acids, respectively; yaks had a similar mRNA sequence as cattle in both genes. The testicular mRNA and protein levels of HAT1 of cattle-yaks were significantly lower than those of yaks, and the protein level of HDAC1 was significantly higher than that of yaks. ELISA showed that the acetylation level of testicular H3K9 was significantly lower in yak hybrids than that of yaks. The present results suggest that the decreased level of HAT1 and increased level of HDAC1 may result in the decreased H3K9 acetylation in cattle-yaks and might be associated with their sterility.