Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
Date (from‐to) : 2009 -2011
Author : HAYASHI Yutaro; KOJIMA Yoshiyuki; MIZUNO Kentaro; KUROKAWA Satoshi
Molecular mechanisms of sex differentiation have been unraveled by gene expression cascade triggered by the SRY gene, but the whole picture still remains unclear. In the present study, to clarify the genetic characteristics of the XX testis without SRY, we histologically analyzed the testicular tissue of patients with 46, XX testicular DSD and attempted to identify the genes with differential expression compared with the XY testis by using PCR-based subtractive hybridization technique. We used specimens obtained from testicular biopsy in boys with 46, XX testicular DSD. Age-matched XY testis derived from hydrocele were used as the control. After PCR-based subtractive hybridization, the subtracted cDNAs were sequenced and analyzed. Further, distribution of candidate genes in the testicular tissue was clarified by immunohistochemistry. The present study was approved by the institutional review board in our university. We finally identified 13 upregulated and 7 downregulated genes in the XX testis. Among the candidate genes, we focused on ROCK1, PQBP1, and UCP2 in the upregulated-gene group and on EEF1A1 in the downregulated-gene group. In immunohistochemistry, ROCK1 protein was detected in the germ cells and Leydig cells, PQBP1 protein in the Leydig cells, and UCP2 protein in the Sertoli cells. From previous reports and in vitro inhibitory assay, it is feasible that ROCK1 phosphorylates and activates SOX9 in Sertoli cells. It is suggested that testis formation is initiated by an alternative signaling pathway attributed to ROCK1 activation, and not SRY activation, in XX testis.