C-FOS-LIKE AND C-JUN-LIKE MESSENGER-RNA EXPRESSION IN FROG (RANA-ESCULENTA) TESTIS DURING THE ANNUAL REPRODUCTIVE-CYCLE

The expression of c-fos and c-jun mRNA has been examined in the testis of a seasonal breeder (the frog, Rana esculenta) during the annual re productive cycle, using Northern blot analysis along with measurements of plasma levels of estradiol-17 beta and androgens (testosterone + 5 alpha-dihydrotestosterone). A c-fos-like transcript of 1.9 kb was rev ealed using a 1.1-kb v-fos probe, while three different transcripts of 3.7, 3.4, and 2.7 kb were seen using 1.0-kb human (h)-c-jun fragment. The proto-oncogene-like mRNAs appear during the period of the year as sociated with the new wave of spermatogenic activity. The levels of fo s-like mRNA were highest after the estradiol-17 beta peak, while low l evels were concomitant with high androgen concentrations. It is conclu ded that there is a close correlation between c-fos- and c-jun-like ex pression and testicular activity in R. esculenta. (C) 1997 Academic Pr ess.