Worm Breeder's Gazette 13(3): 63 (June 1, 1994)
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
We have cloned putative A, B1 and B2 cyclins from C. elegans. Cyclin B1 and B2 are single copy genes while cyclin A belongs to a multigene family. Cyclin A and B2 each correspond to single transcripts while cyclin B1 recognizes three transcripts. The C. elegans temperature sensitive germline defective mutants fem-1 , fem-3 (gf) and glp-4 were used to analyze cyclin germline expression. When hybridizing C. elegans cyclin A or B2 to the mutant RNAs that produce no oocytes, the cyclin A and B2 messages are significantly reduced. When normal numbers of oocytes are produced, the cyclin A and B2 messages are at wild type levels. Therefore, the cyclin A and B2 transcripts appear to be primarily maternal with some somatic component. Consistent with a somatic component, cyclin A and B2 cDNAs cross-hybridize to Ascaris intestinal poly A+ RNA. Hybridization of the cyclin B1 cDNA to these germline defective RNAs suggest that the cyclin B1 transcripts are differentially expressed in the germline. The two larger cyclin B1 transcripts appear to be primarily maternal and the smallest transcript appears to be sperm-specific. The observation that two polyadenylation signals are present in the cyclin B1 3'UTR, as well as results using cyclin B1 probes from specific regions of the B1 3'UTR, suggests that two of the three cyclin B1 transcripts are produced by polyadenylation at different sites. There is precedence in mice and flies for producing tissue-specific transcripts by different use of the cyclin B 3'UTRs. It has been shown in mouse that cyclin B1 hybridizes to four differentially expressed transcripts, one of which is testis-specific. Two of these mouse transcripts differ in the choice of polyadenylation sites and therefore in the lengths of their 3'UTRs (Chapman and Wolgemuth (1992) Mol. Repro. Dev. 33, 259-269). In Drosophila, the cyclin B cDNA detects two female-specific transcripts that are made by splicing of a region of the cyclin B 3'UTR (Dalby and Glover (1992) Development 115, 989-997). In summary, our initial findings show that the C. elegans cyclin As and Bs are highly expressed in the germline and also suggest that the three cyclin B1 transcripts are differentially expressed in oocytes and sperm.