Abstract
Fushi tarazu transcription factor‐1 (FTZ‐F1), a member of a nuclear hormone receptor superfamily, is a transcriptional regulator for fushi tarazu gene expression in Drosophila (Ueda et al., ’90). We have cloned a homologue (rrFTZ‐F1α) of the FTZ‐F1 gene of the frog Rana rugosa. The gene, in frogs, has been shown to have high expression level in the testis (Nakajima et al., 2000). In this study, the RT‐PCR analysis showed that the FTZ‐F1α mRNA level in adult frogs did not change throughout the year, even during hibernation. However, when immunohistological studies using the anti‐rrFTZ‐F1α antibody were employed to examine which testicular cells expressed this gene, Sertoli cells were found to produce rrFTZ‐F1α in the two seasons: the breeding season (from March through May) and the pre‐hibernating season (from October through November). Interstitial cells, however, did it in only the breeding season (from April through May). Taken together, the results suggest that the rrFTZ‐F1α expression is regulated at the post‐transcriptional step, and that the rrFTZ‐F1α may play an important role(s) in the seasonal activities of Sertoli and interstitial cells in the frog testis. J. Exp. Zool. 290:182‐189, 2001. © 2001 Wiley‐Liss, Inc.