摘要
Previous studies have shown that rat epididymis-specific gene HongrES1 plays important roles in sperm capacitation and fertility. In this study, we cloned the mouse homologue gene by sequence alignment and RT-PCR methods and designated it as mHongl. The mHongl gene is located on chromosome 12p14, spanning five exons. The cDNA sequence consists of 1257 nucleotides and encodes a 419 amino-acid protein with a predicted N-terminal signal peptide of 20 amino acids. The mHongl mRNA shows similarity with HongrES1 in the expression patterns： （i） specific expression in epididymal tissue, especially in the cauda region; and （ii） androgen-dependence but testicular fluid factor independence. Its protein product shows 71% similarity with HongrES 1 and contains a classical serpin domain as does HongrES1. A polyclonal antibody against mHongl with high specificity and sensitivity was raised. Like HongrES1, the mHongl protein shows a checker-board expression pattern in the epididymal epithelium and is secreted into the epididymal lumen. The mHongl protein shows higher glycosylation than HongrES1. Although both of them are deposited onto the sperm head surface, mHongl is localized to the equatorial segment, which is different from that of HongrES 1. The mHongl protein can be removed from the sperm membrane by high ionic strength and therefore can be classed as an extrinsic membrane protein. Collectively, we conclude that mHongl is the homologue of HongrES1 and the present work paves the way for establishing animal models to elucidate the precise functions of HongrES1 and mHongl.
Previous studies have shown that rat epididymis-specific gene HongrES1 plays important roles in sperm capacitation and fertility. In this study, we cloned the mouse homologue gene by sequence alignment and RT-PCR methods and designated it as mHongl. The mHongl gene is located on chromosome 12p14, spanning five exons. The cDNA sequence consists of 1257 nucleotides and encodes a 419 amino-acid protein with a predicted N-terminal signal peptide of 20 amino acids. The mHongl mRNA shows similarity with HongrES1 in the expression patterns： （i） specific expression in epididymal tissue, especially in the cauda region; and （ii） androgen-dependence but testicular fluid factor independence. Its protein product shows 71% similarity with HongrES 1 and contains a classical serpin domain as does HongrES1. A polyclonal antibody against mHongl with high specificity and sensitivity was raised. Like HongrES1, the mHongl protein shows a checker-board expression pattern in the epididymal epithelium and is secreted into the epididymal lumen. The mHongl protein shows higher glycosylation than HongrES1. Although both of them are deposited onto the sperm head surface, mHongl is localized to the equatorial segment, which is different from that of HongrES 1. The mHongl protein can be removed from the sperm membrane by high ionic strength and therefore can be classed as an extrinsic membrane protein. Collectively, we conclude that mHongl is the homologue of HongrES1 and the present work paves the way for establishing animal models to elucidate the precise functions of HongrES1 and mHongl.
基金
We thank Dr Qiang Liu for giving some advice and polishing the writing and thank Dr Yu-Chuan Zhou for fruitful discussions. We are also grateful to Ai- H ua Liu fur technical assistance in immunohistochemistry assay. This work was supported by grants from the National Natural Science Foundation of China （No. 30930053） and the Chinese Academy of Sciences Knowledge Innovation Program （No. KSCX2-EW-R-07）.
