Identification and expression of a new sulfhydryl oxidase SOx-3 during thecell cycle and the estrus cycle in uterine cells

Using differential hybridization of a guinea pig endometrial cell cDNA libr ary, a potentially negatively estrogen-regulated gene, SOX-3, was isolated. According to the nucleotide and protein sequence similarities, SOx-3 belon ged to the FAD-linked sulfhydryl oxidase family containing the egg white su lfhydryl oxidase, the rat seminal vesicle sulfhydryl oxidase-2 SOx-2, the q uiescence-inducible protein hQ6. The SOX-3 transcript in the guinea pig as well as 5 different mRNAs in human tissues appeared differentially expresse d in the tissues studied. In secondary endometrial cell culture, the SOX-3 mRNA level increased during a serum depletion-induced quiescence, decreased when cells enter the Gl phase after serum stimulation, and was restored du ring the S and G2/M phases. Thus, SOX-3 could be implicated in the negative cell cycle control. The SOx-3 protein appeared to be specific of epithelia l cells in the uterus. Its expression level varied during the estrus cycle in the guinea pig, suggesting a regulation by steroid hormones. (C) 2001 Ac ademic Press.