Transcriptional regulation of human sperm-associated antigen 16 gene by S-SOX5

Ling Zhang,Wei Li,Shizheng Song,Chaofan Shuang,Qiaoling Zhang,Yunhao Liu,Jie Min,Junpin Liu,Yanwei Li,Zhibing Zhang

doi:10.1186/s12867-017-0082-3

Abstract

BackgroundThe mammalian sperm-associated antigen 16 gene (Spag16) uses alternative promoters to produce two major transcript isoforms (Spag16L and Spag16S) and encode proteins that are involved in the cilia/flagella formation and motility. In silico analysis of both mouse and human SPAG16L promoters reveals the existence of multiple putative SOX5 binding sites. Given that the SOX5 gene encodes a 48-kDa transcription factor (S-SOX5) and the presence of putative SOX5 binding sites at the SPAG16L promoter, regulation of SPAG16L expression by S-SOX5 was studied in the present work.ResultsS-SOX5 activated human SPAG16L promoter activity in the human bronchial epithelia cell line BEAS-2B cells. Mutation of S-SOX5 binding sites abolished the stimulatory effect. Overexpression of S-SOX5 resulted in a significant increase in the abundance of SPAG16L transcripts whereas silencing of S-SOX5 by RNAi largely reduced the SPAG16L expression. Chromatin immunoprecipitation assays showed that S-SOX5 directly interacts with the SPAG16L promoter.ConclusionS-SOX5 regulates transcription of human SPAG16L gene via directly binding to the promoter of SPAG16L. It has been reported that expression of sperm-associated antigen 6 (SPAG6), encoding another axonemal protein, is activated by S-SOX5. Therefore, S-SOX5 may regulate formation of motile cilia/flagella through globally mediating expression of genes encoding axonemal proteins.

Highlights

The mammalian sperm-associated antigen 16 gene (Spag16) uses alternative promoters to produce two major transcript isoforms (Spag16L and Spag16S) and encode proteins that are involved in the cilia/flagella formation and motility
These results indicate that S-SOX5 stimulates transcription of human SPAG16L
The results suggest that the P-I site probably contributes to the repression of SPAG16L by unknown factor(s) in the absence of S-SOX5 and is essential for activation of SPAG16L by S-SOX5

Summary

Introduction

The mammalian sperm-associated antigen 16 gene (Spag16) uses alternative promoters to produce two major transcript isoforms (Spag16L and Spag16S) and encode proteins that are involved in the cilia/flagella formation and motility. Given that the SOX5 gene encodes a 48-kDa transcription factor (S-SOX5) and the presence of putative SOX5 binding sites at the SPAG16L promoter, regulation of SPAG16L expression by S-SOX5 was studied in the present work. Based on phylogenic analysis of HMG domain sequences and full-length protein sequences/functional features, Sox genes are classified into 10 groups from A to J [3]. They display distinct tissue-specific expression patterns and have been implicated in regulation of a wide range of developmental processes [1]. S-SOX5, which lacks N-terminal domain required for dimerization with other SOXD proteins, is predominantly detected in testis and brain while L-SOX5 is expressed in multiple tissues including testis, heart, liver

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