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Functional analysis of the SRY—KRAB interaction in mouse sex determination
Author(s) -
Polanco Juan Carlos,
Wilhelm Dagmar,
Mizusaki Hirofumi,
Jackson Andrew,
Browne Catherine,
Davidson Tara,
Harley Vincent,
Sinclair Andrew,
Koopman Peter
Publication year - 2009
Publication title -
biology of the cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 85
eISSN - 1768-322X
pISSN - 0248-4900
DOI - 10.1042/bc20080061
Subject(s) - testis determining factor , biology , gene knockdown , krüppel , genetics , pdz domain , gene , small hairpin rna , sex reversal , microbiology and biotechnology , gene expression , y chromosome
Background information . SRY (sex‐determining region Y), the master regulator of male development in mammals, has been studied extensively for more than 17 years, but how the SRY protein triggers the chain of events leading to testis development remains unclear. SRY probably requires a partner protein to elicit its molecular function. KRAB‐O, a novel protein containing a KRAB (Krüppel‐associated box) domain only, was suggested recently as a candidate SRY partner. In order to investigate the possible role of KRAB‐O in sex determination, we studied its expression and conducted functional assays of the SRY—KRAB interaction. Results . More than 100 KRAB genes were found to be expressed in mouse developing gonads, including 19 transcripts encoded by the KRAB ‐ O cluster that were found to be expressed in somatic cells at 11.5 dpc (days post‐coitum). Loss‐of‐function analysis in Sry ‐expressing cultured cells, using shRNA (small hairpin RNA) constructs directed against KRAB ‐ O and its homologous genes, resulted in a reduced ability to up‐regulate Sox9 [SRY‐related HMG (high‐mobility group)‐box 9]; however, KRAB‐knockdown mice exhibited normal testis development. Conclusions . Reduced Sox9 expression in KRAB ‐knockdown cells supports a role for KRAB‐O and perhaps other KRAB genes in mediating SRY function. Overlapping expression and potential redundancy between members of the large KRAB ‐ O gene cluster may mask any loss‐of‐function in vivo , presenting clear challenges for further functional analysis.