title: Expression of inhibin-alpha is regulated synergistically by Wilms' tumor gene 1 (Wt1) and steroidogenic factor-1 (Sf1) in sertoli cells.
abstract: Wt1 encodes a zinc finger nuclear transcriptional factor, which is specifically expressed in testicular Sertoli cells and knockdown of Wt1 in Sertoli cells causes male mice subfertility. However, the underlying mechanism is still unclear. In this study, we found that expression of inhibin-α is significantly reduced in Wt1-deficient Sertoli cells. Luciferase assays using the inhibin-α promoter indicated that the inhibin-α promoter is transactivated by the Wt1 A, and B isoforms (-KTS), but not the C, and D isoforms (+KTS). Analysis of the Wt1 responsive element of the inhibin-α promoter region using site-directed mutagenesis showed that the nucleotides between -58 and -49 are essential for Wt1-dependent transactivation of the inhibin-α promoter. ChIP assays indicated that Wt1 directly interacts with the inhibin-α promoter. In addition, the inhibin-α promoter is activated synergistically by Wt1 and Sf1. Mutation of the ligand binding domain (LBD) of Sf1 (residues 235-238) completely abolished the synergistic action between Wt1 and Sf1, but did not affect the physical interaction between these two proteins, suggesting that other factor(s) may also be involved in the regulation of inhibin-α in Sertoli cells. Further studies demonstrated that β-catenin enhances the synergistic activation of Wt1 and Sf1 on the inhibin-α promoter. Given the fact that inhibin-α, a subunit of inhibin, is known to be involved in the regulation of spermatogenesis and testicular steroidogenesis, this study reveals a new regulatory mechanism of inhibin-α in Sertoli cells and also sheds light on the physiological functions of Wt1 in gonad development and spermatogenesis.
authors: State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
authors: Shao-Yang
authors: SY
authors: Ji
authors: Jian-Xiu
authors: JX
authors: Hao
authors: Lei
authors: L
authors: Li
authors: Jun
authors: J
authors: Zhang
authors: Qiao-Song
authors: QS
authors: Zheng
authors: Xi-Xia
authors: XX
authors: Li
authors: Xiao-Na
authors: XN
authors: Wang
authors: Chun-Sheng
authors: CS
authors: Han
authors: Fei
authors: F
authors: Gao
authors: Yi-Xun
authors: YX
authors: Liu
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D015153:Blotting, Western; D002460:Cell Line; D002478:Cells, Cultured; D005260:Female; D005786:Gene Expression Regulation; D007265:Inhibins / Q000235:genetics* / Q000378:metabolism; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009154:Mutation; D011401:Promoter Regions, Genetic / Q000235:genetics; D020033:Protein Isoforms / Q000235:genetics; D020218:Response Elements / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012708:Sertoli Cells / Q000378:metabolism*; D054339:Steroidogenic Factor 1 / Q000235:genetics* / Q000378:metabolism; D015533:Transcriptional Activation; D025721:WT1 Proteins / Q000235:genetics* / Q000378:metabolism; D060449:Wnt Signaling Pathway / Q000235:genetics
chemical_list: D020033:Protein Isoforms; D054339:Steroidogenic Factor 1; D025721:WT1 Proteins; C094377:inhibin-alpha subunit; D007265:Inhibins