GATA factors and androgen receptor collaborate to transcriptionally activate the Rhox5 homeobox gene in Sertoli cells.
How Sertoli-specific expression is initiated is poorly understood. Here, we address this issue using the proximal promoter (Pp) from the Rhox5 homeobox gene. Its Sertoli cell-specific expression is achieved, in part, through a negative regulatory element that inhibits Pp transcription in non-Sertoli cell lines. Complementing this negative regulation is positive regulation conferred by four androgen-response elements (AREs) that interact with the androgen receptor (AR), a nuclear hormone receptor expressed at high levels in Sertoli cells. A third control mechanism is provided by a consensus GATA-binding site that is crucial for Pp transcription both in vitro and in vivo. Several lines of evidence suggested that GATA factors and AR act cooperatively to activate Pp transcription: (i) the GATA-binding site crucial for Pp transcription is in close proximity to two of the AREs, (ii) GATA and AR form a complex with the Pp in vitro, (iii) overexpression of GATA factors rescued expression from mutant Pp constructs harboring defective AREs, and (iv) incubation of a Sertoli cell line with testosterone triggered corecruitment of AR and GATA4 to the Pp. Collectively, our results suggest that the Rhox5 gene achieves Sertoli cell-specific transcription using a combinatorial strategy involving negative and cooperative positive regulation.
Bhardwaj
Anjana
A
Department of Biochemistry and Molecular Biology, Unit 1000, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
Rao
Manjeet K
MK
Kaur
Ramneet
R
Buttigieg
Miriam R
MR
Wilkinson
Miles F
MF
D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D050980:GATA Transcription Factors / Q000502:physiology*; D005801:Genes, Homeobox; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D011401:Promoter Regions, Genetic / Q000235:genetics*; D017430:Prostate-Specific Antigen / Q000235:genetics; D025941:Protein Interaction Mapping; D011944:Receptors, Androgen / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000502:physiology; D020218:Response Elements / Q000235:genetics; D012708:Sertoli Cells / Q000378:metabolism*; D013737:Testis / Q000196:embryology / Q000254:growth & development; D019076:Transgenes
D050980:GATA Transcription Factors; D011944:Receptors, Androgen; D011993:Recombinant Fusion Proteins; D017430:Prostate-Specific Antigen