title: Molecular cloning, gene expression and methylation status analysis of PIWIL1 in cattle-yaks and the parental generation.
abstract: The PIWI-like protein 1 (PIWIL1) plays an important role in spermatogenesis and transposon control. In mammals, the absence of the PIWIL1 gene can lead to over-expression of retrotransposons, spermatogenetic arrest, and male infertility. To assess whether the PIWIL1 gene is associated with the male sterility of cattle-yaks, we examined PIWIL1 and LINE-1 (long interspersed element-1) retrotransposon mRNA expression and DNA methylation patterns in the testes of cattle, yaks, and cattle-yaks. Our results indicate that PIWIL1 mRNA expression in the testes of cattle-yaks is significantly lower than that of cattle or yaks. Correlating with decreased gene expression, we also found that the methylation levels of the PIWIL1 gene in cattle-yaks were significantly higher than in cattle or yaks. However, even though LINE-1 element expressed higher mRNA levels in the testes of cattle-yaks than in their parents, DNA methylation patterns were un-altered. Our results suggest that the higher methylation levels of the PIWIL1 gene in cattle-yaks coincides with decreased PIWIL1 mRNA expression, thereby affecting the transposon silencing mechanism and possibly contributing to cattle-yak male sterility.
authors.affiliation: Laboratory of Animal Reproductive Genetics and Molecular Evolution, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Gu
authors.forename: Qifa
authors.initials: Q
authors.lastname: Li
authors.forename: Zengxiang
authors.initials: Z
authors.lastname: Pan
authors.forename: Minggui
authors.initials: M
authors.lastname: Li
authors.forename: Hua
authors.initials: H
authors.lastname: Luo
authors.forename: Zhuang
authors.initials: Z
authors.lastname: Xie
mesh_terms: D000818:Animals; D060565:Argonaute Proteins / Q000235:genetics / Q000502:physiology*; D002417:Cattle / Q000235:genetics / Q000502:physiology*; D003001:Cloning, Molecular; D003433:Crosses, Genetic; D018628:Gene Dosage; D005786:Gene Expression Regulation / Q000235:genetics / Q000502:physiology*; D007248:Infertility, Male / Q000235:genetics / Q000503:physiopathology*; D008297:Male; D008745:Methylation; D012313:RNA / Q000737:chemistry / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D060565:Argonaute Proteins; D012313:RNA
keywords: Cattle-yaks; DNA methylation; LINE-1 element; Male sterility; PIWIL1; mRNA expression