Molecular cloning, functional characterization, and gene expression of a follicle-stimulating hormone receptor in the testis of newt Cynops pyrrhogaster

We previously demonstrated in vitro that mammalian follicle-stimulating hor mone (FSH) stimulates the proliferation of newt secondary spermatogonia and their differentiation into primary spermatocytes. In the current study, we isolated a cDNA from newt testis that encodes a FSH receptor (FSH-R). The total sequence homology in the deduced protein of the newt was approximatel y 70% with mammalian FSH-Rs. Mammalian cells, transiently transfected with the cloned newt FSH-R cDNA, displayed specific binding to [I-125] human FSK and cAMP accumulation, indicating that the cloned cDNA encodes a functiona l newt FSH-R protein. Northern blot analysis revealed a single transcript o f approximately 3.0 kb length that was synthesized in testicular somatic ce lls (mainly Sertoli cells) from spermatogonial to spermatid stages with the highest level expressed during the primary spermatocytes stage. These resu lts demonstrate that FSH stimulates newt spermatogenesis through the FSH-R. This study, as far as we know, reports for the first time the cloning of a n amphibian FSH-R cDNA (C) 2000 Academic Press.