AIMAlthough epidermal growth factor receptors are expressed in the testes, whether they signal through epidermal growth factor receptor pathway substrate 8 (Eps8) is unknown. Here we evaluated the expression pattern of Eps8 in the maturing testis.

METHODSThe expression of Eps8 was analysed by Northern blotting, immunocytochemistry and Western blotting in primary Sertoli cell cultures and in testicular tissue of rodents.

RESULTSEps8 is specifically expressed in gonocytes, Leydig and Sertoli cells of the neonatal rats and in Leydig and Sertoli cells of the adult rats and mice. Although gonocytes express Eps8, no signal was found in prepubertal or mature spermatogonia and the expression level of Eps8 in Sertoli cells increases with age. No regulation of Eps8 expression in primary immature rat Sertoli cells by Follicle stimulating hormone (FSH) was detected by Western blotting.

CONCLUSIONEps8 seems to be involved in the growth factor-controlled regulation of cell proliferation and differentiation in the seminiferous epithelium. Eps8 is a possible marker for gonocytes and in Sertoli cells it could be involved in crosstalk with other growth factor pathways.

Adaptor Proteins, Signal Transducing ; Animals ; Base Sequence ; Blotting, Northern ; Cell Line ; DNA Primers ; Gene Expression Regulation, Developmental ; Immunohistochemistry ; Leydig Cells ; cytology ; physiology ; Male ; Proteins ; genetics ; RNA ; genetics ; isolation & purification ; Rats ; Rats, Sprague-Dawley ; Sertoli Cells ; physiology ; Sexual Maturation ; Spermatocytes ; cytology ; physiology ; Testis ; growth & development

AIMTo specifically express the Asp567Gly human follicle-stimulating hormone receptor (FSHR) under the control of its promoter to evaluate the phenotypic consequences in the presence of normal pituitary function.

METHODSWe produced transgenic mice overexpressing the Asp567Gly human FSHR under the control of a 1.5kb 5'-flanking region fragment of its promoter.

RESULTSMice were phenotypically normal and fertile. In males, mRNA could be detected in the testis and the brain, indicating that the 1.5kb promoter fragment drives expression not only in the gonads. The testis weight/body weight ratio and the testosterone levels in transgenic and non-transgenic littermates were similar. By in situ hybridisation we found that the transgenic FSHR was highly expressed in Sertoli cells, spermatocytes and round spermatids. However, a radioligand receptor assay failed to show a significant difference in total FSHR binding sites in testis homogenates of transgenic and wild type animals, suggesting that the transgenic FSHR is probably not translated into functional receptor protein.

CONCLUSIONA 1.5kb 5'-region of the human FSHR drives mRNA expression of the transgene in the testis but leads to ectopic expression in germ cells and in the brain. No phenotypic consequences could be documented due to the lack of protein expression.

Animals ; Body Weight ; Brain Chemistry ; Gene Expression ; Gene Targeting ; Humans ; In Situ Hybridization ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Inbred DBA ; Mice, Transgenic ; Mutagenesis ; Organ Size ; Promoter Regions, Genetic ; physiology ; RNA, Messenger ; analysis ; Receptors, FSH ; chemistry ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Sertoli Cells ; chemistry ; Testis ; anatomy & histology ; chemistry ; metabolism ; Testosterone ; blood