Male Reproductive Tract

Developmental Expression and Gene Regulation of Insulin-like 3 Receptor RXFP2 in Mouse Male Reproductive Organs

Abstract
The mutations of testicular insulin-like 3 (INSL3) hormone or its receptor RXFP2 cause cryptorchidism in male mice. Here we have examined Rxfp2 gene expression at different stages of embryonic and postnatal mouse development in male reproductive tissues employing quantitative RT-PCR and several RXFP2-specific antibodies directed towards different parts of the RXFP2 protein. Receptor expression was markedly increased after birth and readily detectable in the epididymis, Leydig and germ cells of the testis. The strongest expression was detected in adult mouse cremaster muscle. INSL3 treatment increased cell proliferation of embryonic gubernacular and TM3 embryonic Leydig cells implicating active INSL3-mediated autocrine signaling in these cells and identifying TM3 as a novel in vitro model to study the effects of RXFP2 signaling. We generated Tg(Rxfp2-icre)AIA (Rxfp2-iCre) transgenic mice expressing improved Cre recombinase (iCre) under the control of the 2.4kb mouse Rxfp2 promoter. The iCre was expressed in the gubernacular ligament at E14.5 indicating that this promoter is able to drive Rxfp2 gene expression during trans-abdominal testis descent. We demonstrated that the transcription factor Sox9, a known male sex determination factor, is expressed in mouse embryonic gubernacula and upregulated human, but not mouse promoter luciferase reporter constructs. In conclusion, we have determined the developmental expression profile of INSL3 receptor employing newly characterized RXFP2 antisera and a novel Rxfp2-iCre transgenic mouse model. We determined the promoter region capable to provide the gubernacular-specific expression of Rxfp2. Analysis of RXFP2 promoter identified SOX9 as a new transcriptional enhancer of human gene expression.

Key words: Embryo • Male Reproductive Tract • Testis • Leydig cells • RXFP2/LGR8

This article has been cited by other articles:

				C. Foresta, D. Zuccarello, A. Garolla, and A. Ferlin Role of Hormones, Genes, and Environment in Human Cryptorchidism Endocr. Rev., August 1, 2008; 29(5): 560 - 580. [Abstract] [Full Text] [PDF]

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