Sertoli cell androgen receptor DNA binding domain is essential for the completion of spermatogenesis.
We examined the biological importance of Sertoli cell androgen receptor (AR) genomic interaction, using a Cre-loxP approach to selectively disrupt the AR DNA-binding domain (AR-DBD). Sertoli cell (SC)-specific transgenic Abpa or AMH promoters targeted Cre-mediated inframe excision of mouse Ar exon-3, encoding the AR-DBD second zinc-finger (ZF2), generating SC-specific mutant AR(DeltaZF2) lines designated Abp.SCAR(DeltaZF2) and AMH.SCAR(DeltaZF2), respectively. Both SCAR(DeltaZF2) lines produced infertile males exhibiting spermatogenic arrest, despite normal SC numbers and immunolocalized SC nuclear AR. Adult homozygous TgCre((+/+)) SCAR(DeltaZF2) or double-TgCre((+/-)) Abp/AMH.SCAR(DeltaZF2) males displayed equivalent small testes 30% of normal size, representing maximal Cre-loxP-disruption of Sertoli AR function. Hemizygous TgCre((+/-)) vs. homozygous TgCre((+/+)) Abp.SCAR(DeltaZF2) testes were larger (47% normal size) with more postmeiotic development, indicating dose-dependent Cre-mediated disruption of SC-specific AR-DBD activity. SCAR(DeltaZF2) males exhibited adult Leydig cell hypertrophy but normal serum testosterone levels. Sertoli cell-specific Rhox5 and Spinlw1 transcription, regulated by divergent or classical androgen-response elements, respectively, were both decreased in postnatal SCAR(DeltaZF2) vs. control testes, demonstrating SC-specific AR-DBD function as early as postnatal d 5. However, Rhox5 expression declined dose-dependently, whereas Spinlw1 expression increased, in adult TgCre((+/-)) and TgCre((+/+)) SCAR(DeltaZF2) testes, revealing differential temporal control for distinct AR-regulated transcripts. Androgen-repressed Ngfr was not up-regulated in SCAR(DeltaZF2) testes, suggesting maintenance of a nonclassical mechanism independent of AR-DBD. Thus, our unique SCAR(DeltaZF2) paradigm provided dose-dependent Cre-mediated disruption of testicular development and gene expression revealing that the AR-DBD is essential for SC function and postmeiotic spermatogenesis. Nongenomic or AR-DBD-independent pathways appear secondary or play no major independent role in SC function.
Lim
Patrick
P
Andrology Laboratory, ANZAC Research Institute, Concord Hospital, Sydney, New South Wales 2139, Australia.
Robson
Mathew
M
Spaliviero
Jenny
J
McTavish
Kirsten J
KJ
Jimenez
Mark
M
Zajac
Jeffrey D
JD
Handelsman
David J
DJ
Allan
Charles M
CM
D000818:Animals; D002448:Cell Adhesion; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D015870:Gene Expression; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009929:Organ Size; D010641:Phenotype; D054730:Protein Interaction Domains and Motifs; D011944:Receptors, Androgen / Q000378:metabolism*; D012708:Sertoli Cells / Q000378:metabolism*; D013091:Spermatogenesis; D013737:Testis / Q000033:anatomy & histology; D019076:Transgenes
D004268:DNA-Binding Proteins; D011944:Receptors, Androgen; D004247:DNA