Nuclear receptors, testosterone, and posttranslational modifications in human INSL3 promoter activity in testicular Leydig cells.
Insulin-like peptide 3 (INSL3) is a hormone produced by fetal and adult Leydig cells of the mammalian testis. During embryonic life INSL3 is required for testicular descent, whereas in adults it is involved in bone metabolism and male germ cell survival. Despite these important roles, the molecular mechanisms regulating INSL3 expression remain poorly understood. So far, two transcription factors have been implicated in INSL3 transcription: the nuclear receptors SF1 and NUR77. Circumstantial evidence also points to a role for androgens. Using transient transfections in MA-10 Leydig cells, we found that testosterone regulates in a time- and dose-dependent manner the human INSL3 promoter. The INSL3 promoter, however, does not contain a classical androgen-responsive element. Testosterone responsiveness was found to be mediated through an element located in the proximal INSL3 promoter, which also contains a NUR77-SF1-binding site. Furthermore, we found that posttranslational modifications, such as phosphorylation and acetylation, modulate transcription factor activity and therefore also contribute to INSL3 promoter activity in Leydig cells. All together, these data provide new insights into the molecular mechanisms regulating INSL3 expression in the mammalian testis.
Reproduction, Perinatal and Child Health, CHUQ Research Centre, Québec City, Québec, Canada. Jacques-J.Tremblay@crchul.ulaval.ca
Jacques J
JJ
Tremblay
Nicholas M
NM
Robert
Eric
E
Laguë
D000107:Acetylation / Q000187:drug effects; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics; D006801:Humans; D007328:Insulin / Q000235:genetics*; D007985:Leydig Cells / Q000187:drug effects* / Q000378:metabolism*; D008297:Male; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D010766:Phosphorylation / Q000187:drug effects; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011506:Proteins / Q000235:genetics*; D000072260:RNA Splicing Factors; D011987:Receptors, Steroid; D013739:Testosterone / Q000494:pharmacology*; D014157:Transcription Factors / Q000494:pharmacology*; D014162:Transfection
D004268:DNA-Binding Proteins; D007328:Insulin; C084797:Leydig insulin-like protein; C539821:NR4A1 protein, human; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D011506:Proteins; D000072260:RNA Splicing Factors; D011987:Receptors, Steroid; C107467:SF1 protein, human; D014157:Transcription Factors; D013739:Testosterone