Transcription profiling of wild type and XY Nrg1 knock out male pooled embryonic gonads to decipher the role of this gene in sexual differentiation

In mammals, sex determination depends on the paternal transmission of the Y chromosome, which bears the Sry gene. At the time of sex determination, Sry becomes up-regulated in XY gonads initiating the expression of various factors required for testicular development. Most of these factors remain to be identified. As a consequence, the genetic causes of gonadal dysgenesis in human patients, other than those involving SRY, remain unknown. We found that Nrg1 is a new gene involved in early testicular development. To study the role of Nrg1 in embryonic testicular differentiation, conditional inactivation of Nrg1 was achieved with the help of a Wt1-Cre line. Mutant mice show defects of testis development. In order to correlate the defects of cellular processes and the misregulated gene network(s), expression profiles were examined in controls and mutants testes at 13.5 dpc. Each testis sample was pooled from eight embryos.