247. Expression of components of the hedgehog signalling pathway during murine spermatogenesis
A. Szczepny A B , D. A. Jans B C , G. Hime B D and K. L. Loveland A BA Monash Institute of Medical Research, Monash University, Clayton, VIC, Australia
B ARC Centre of Excellence in Biotechnology and Development, Australia
C Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
D Department of Anatomy and Cell Biology, Melbourne University, Parkville, VIC, Australia
Reproduction, Fertility and Development 17(9) 98-98 https://doi.org/10.1071/SRB05Abs247
Submitted: 26 July 2005 Accepted: 26 July 2005 Published: 5 September 2005
Abstract
Hedgehog (Hh) signalling is best known for its involvement in regulating patterning, driving cell proliferation, promoting cell survival and directing differentiation during embryonic development.1 The role that Hedgehog signalling plays in the testis is not yet clearly defined, though deletion of one Hedgehog ligand, Dhh, leads to male infertility. The Gli family of zinc finger TFs, consisting of Gli1, Gli2 and Gli3, are mediators of the Hh signalling cascade in vertebrates. We have previously shown that the mRNA transcripts encoding all three Glis in the adult mouse testis are expressed highly in spermatogonia, spermatocytes and to a lower extent in the round spermatids. To understand the potential sites of action of Hh proteins in spermatogenesis, we have extended our analysis to other genes involved in the Hh signalling pathway in the adult mouse testis. Using in situ hybridization, Patched2, a transmembrane receptor for Hh, was detected in spermatogonia and spermatocytes, with an apparently lower expression in the round spermatids. The mRNA of Smoothened, another transmembrane protein which forms a membrane receptor complex with Patched, is highly expressed in spermatogonia and spermatocytes, again showing lower expression in round spermatids and interstitial cells. Fused, a positive regulator of Hh signalling, is highly expressed in spermatogonia and spermatocytes with slightly lower expression in round spermatids. SuFu is a negative regulator of Hh signalling, known to repress Gli1 function in part by tethering it in the cytoplasm. The mRNA encoding SuFu is absent from spermatogonia, detected in spermatocytes and persists in round spermatids where its expression appears highest, suggesting that the SuFu protein may be acting to switch off Hh signalling at that stage of spermatogenesis. Overall, the regulated expression pattern of these genes in the adult mouse testis suggests a role for Hh signalling in the regulation of spermatogenesis.
(1) Ruiz i Altaba A. (1999) Trends Genet. 15(10), 418–425.
