title: Inhibition of SRY-calmodulin complex formation induces ectopic expression of ovarian cell markers in developing XY gonads.
abstract: The transcription factor sex-determining region of the Y chromosome (SRY) plays a key role in human sex determination, because mutations in SRY cause disorders of sex development in XY individuals. During gonadal development, Sry in pre-Sertoli cells activates Sox9 gene transcription, committing the fate of the bipotential gonad to become a testis rather than an ovary. The high-mobility group domain of human SRY contains two independent nuclear localization signals, one bound by calmodulin (CaM) and the other by importin-β. Although XY females carry SRY mutations in these nuclear localization signals that affect SRY nuclear import in transfected cells, it is not known whether these transport mechanisms are essential for gonadal development and sex determination. Here, we show that mouse Sry protein binds CaM and that a CaM antagonist reduces CaM binding, nuclear accumulation, and transcriptional activity of Sry in transfected cells. CaM antagonist treatment of cultured, sexually indifferent XY mouse fetal gonads led to reduced expression of the Sry target gene Sox9, defects in testicular cord formation, and ectopic expression of the ovarian markers Rspondin1 and forkhead box L2. These results indicate the importance of CaM for SRY nuclear import, transcriptional activity, testis differentiation, and sex determination.
authors.affiliation: Molecular Genetics and Development Division, Prince Henry's Institute of Medical Research, Level 4 Block E, Monash Medical Centre, 246 Clayton Road, Clayton, Melbourne, Victoria 3168, Australia.
authors.forename: Helena
authors.initials: H
authors.lastname: Sim
authors.forename: Anthony
authors.initials: A
authors.lastname: Argentaro
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Czech
authors.forename: Stefan
authors.initials: S
authors.lastname: Bagheri-Fam
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Sinclair
authors.forename: Peter
authors.initials: P
authors.lastname: Koopman
authors.forename: Brigitte
authors.initials: B
authors.lastname: Boizet-Bonhoure
authors.forename: Francis
authors.initials: F
authors.lastname: Poulat
authors.forename: Vincent R
authors.initials: VR
authors.lastname: Harley
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000187:drug effects*; D000818:Animals; D000943:Antigens, Differentiation / Q000378:metabolism*; D019556:COS Cells; D002147:Calmodulin / Q000037:antagonists & inhibitors* / Q000378:metabolism; D002148:Calmodulin-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism / Q000648:ultrastructure; D002522:Chlorocebus aethiops; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism; D000074842:Forkhead Box Protein L2; D051858:Forkhead Transcription Factors / Q000378:metabolism; D008297:Male; D051379:Mice; D009924:Organ Culture Techniques; D011994:Recombinant Proteins / Q000378:metabolism; D055758:SOX9 Transcription Factor / Q000235:genetics / Q000378:metabolism; D019849:Sex Determination Processes / Q000187:drug effects; D051876:Sex-Determining Region Y Protein / Q000235:genetics / Q000378:metabolism*; D013085:Spermatic Cord / Q000187:drug effects; D013091:Spermatogenesis; D013737:Testis / Q000502:physiology* / Q000648:ultrastructure; D019699:Thrombospondins / Q000378:metabolism; D015533:Transcriptional Activation / Q000187:drug effects
chemical_list: D000943:Antigens, Differentiation; D002147:Calmodulin; D002148:Calmodulin-Binding Proteins; D000074842:Forkhead Box Protein L2; D051858:Forkhead Transcription Factors; C498893:Foxl2 protein, mouse; C518903:RSPO1 protein, mouse; D011994:Recombinant Proteins; D055758:SOX9 Transcription Factor; D051876:Sex-Determining Region Y Protein; C527933:Sox9 protein, mouse; C497746:Sry protein, mouse; D019699:Thrombospondins