SMAD expression in the testis: an insight into BMP regulation of spermatogenesis.
Bone morphogenetic proteins (BMPs), members of the transforming growth factor-beta superfamily, extensively influence events that establish male fertility, affecting germ cells and somatic cells throughout fetal and postnatal life. BMP signals are relayed by SMAD proteins, transcription factors that translocate to the nucleus upon ligand stimulation. We show that BMP signaling in the testis may be regulated by selective expression of BMP-responsive and inhibitory SMADs, with expression differing between the first wave and adult spermatogenesis. Smad1, Smad5, Smad8, Smad4, Smad6, and Smad7 expression is ubiquitous during testis development but becomes cell-specific in the adult. Furthermore, regulated SMAD6 protein expression at the onset of spermatogenesis suggests differential responsiveness of spermatogonial subpopulations to ligands. In vitro, immature Sertoli cells and spermatogonia transduce BMP2 and BMP4 signals by means of SMAD1, SMAD5, and SMAD8. Based on these findings, we extrapolate these data to interpret BMP mutant testis phenotypes in terms of SMAD availability for signal transduction.
Itman
Catherine
C
Monash Institute of Medical Research, and the Australian Research Council Centre of Excellence in Biotechnology and Development, Monash University, Melbourne, Victoria, Australia.
Loveland
Kate Lakoski
KL
D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D002478:Cells, Cultured; D005455:Fluorescent Antibody Technique; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051785:Smad Proteins / Q000235:genetics* / Q000378:metabolism; D051898:Smad1 Protein / Q000235:genetics / Q000378:metabolism; D051901:Smad4 Protein / Q000235:genetics / Q000378:metabolism; D051902:Smad5 Protein / Q000235:genetics / Q000378:metabolism; D051906:Smad7 Protein / Q000235:genetics / Q000378:metabolism; D051904:Smad8 Protein / Q000235:genetics / Q000378:metabolism; D013091:Spermatogenesis / Q000187:drug effects* / Q000235:genetics; D013737:Testis / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology
C525719:Bmp2 protein, mouse; C525810:Bmp4 protein, mouse; D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D051785:Smad Proteins; D051898:Smad1 Protein; D051901:Smad4 Protein; D051902:Smad5 Protein; D051906:Smad7 Protein; D051904:Smad8 Protein; D016212:Transforming Growth Factor beta