The regulated expression of c-IAP1 and c-IAP2 during the rat seminiferous epithelial cycle plays a role in the protection of germ cells from Fas-mediated apoptosis.
The inhibitor of apoptosis proteins, c-IAP1 and c-IAP2, are highly expressed in rat testis and potentially play a regulatory role in testicular apoptosis. To better understand their functions during spermatogenesis, we have analyzed their spatio-temporal distribution in rat testis, how their expression is controlled by the paracrine stem-cell factor (SCF) and how they affect Fas-mediated apoptosis. Both c-IAP1 and c-IAP2 showed cycles of transcriptional expression, throughout the seminiferous epithelial cycle. c-IAP1 protein showed a diffuse nuclear distribution in type B spermatogonia, preleptotene, leptotene, and zygotene spermatocytes. In pachytene spermatocytes, c-IAP1 colocalized with SUMO-1 in the XY-body. c-IAP2 protein was cytoplasmic in spermatocytes, from stage VI pachytene onwards, round spermatids, elongated spermatids and Leydig cells. Its expression was upregulated by SCF. Inhibition of IAP activity resulted in a greater sensitivity of germ cells to Fas-mediated apoptosis. These results suggest an important role for IAPs in the regulation of spermatogenic apoptosis.
Wang
Yangyang
Y
Department of Physiology and Pediatrics, University of Turku, Kiinamyllynkatu 10, Turku 20520, Finland. yanwan@utu.fi
Suominen
Janne S
JS
Parvinen
Martti
M
Rivero-Muller
Adolfo
A
Kiiveri
Sanne
S
Heikinheimo
Markku
M
Robbins
Ian
I
Toppari
Jorma
J
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D020169:Caspases / Q000502:physiology; D002453:Cell Cycle / Q000235:genetics / Q000502:physiology; D004789:Enzyme Activation; D005786:Gene Expression Regulation; D007150:Immunohistochemistry; D051034:Inhibitor of Apoptosis Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012670:Seminiferous Epithelium / Q000166:cytology / Q000502:physiology*; D013091:Spermatogenesis / Q000235:genetics / Q000502:physiology; D013094:Spermatozoa / Q000166:cytology / Q000502:physiology*; D019089:Stem Cell Factor / Q000502:physiology; D013737:Testis / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects; D019014:fas Receptor / Q000494:pharmacology / Q000502:physiology*
D051034:Inhibitor of Apoptosis Proteins; D019089:Stem Cell Factor; D019014:fas Receptor; D020169:Caspases