Analysis of responsive genes of murine Leydig cells by 2,3,7,8-tetrachlorodibenzo-p-dioxin

We examined the effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on changes in gene expression of murine testicular Leydig TM3 cells by a method of differential mRNA display based on a PCR technique. Although no change in viable cell number was observed by TCDD at the concentration of 10 nM, Ah receptor mRNA was down-regulated and CYP1A1 was induced in TM3 cells. One hundred and sixty-one PCR products, differentially expressed in 2% agarose gel electrophoresis after PCR amplification, were detected. Nine cDNAs were confirmed to be differentially expressed in Northern ELISA analysis. Two cDNAs were cloned and sequenced. One was identical to Homo sapiens Nedd-4-like ubiquitin-protein ligase WWP2 (WW domain-containing protein), which is associated with the ubiquitin proteolytic process. TCDD decreased expression of WWP2, which might cause the suppression of proteolytic process. The other was identical to the mouse expressed sequence tag. The function of this gene was not known. These genes might provide information for understanding TCDD-induced toxicity or biological responses.