Worm Breeder's Gazette 13(4): 60 (October 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.
NEC Fundamental Research Laboratories, Tsukuba, Ibaraki 305, Japan.
Typical tumor-promoting phorbol esters (TPA and PDD) cause severe disorders in the growth and behavior of C. elegans. The tpa-1 gene, which mediates the action of the agents, encodes a protein kinase C (PKC) homolog. The tpa-1 gene consists of eleven exons and spans a genomic region of about 20 kb. Two mRNA species, 2.8 kb and 2.4 kb, are transcribed from the tpa-1 locus and both are trans-spliced to SL1 .The former contains all the eleven exons and codes for a protein of 80 kDa ( TPA-1 A);on the other hand, the latter lacks the first four exons and codes for a 65-kDa protein ( TPA-1 B)without some 150 amino acids at the amino-terminal portion of TPA-1 A(Sano et al. C. elegans meeting '93, see Figure). In order to examine whether the two mRNA species are produced by two alternate promoters, we have tried to rescue a TPA-resistant mutant strain, MJ563 ,by microinjecting genomic fragments of the tpa-1 gene, variously lacking its 5' region. Microinjection of plasmid constructs of these fragments showed rescuing activity. One of these rescuing constructs, pSK14 ,contained a fragment covering only about 1 kb upstream of the 5th exon through the end of tpa-1 ,indicating that there is another promoter within 1 kb upstream of the 5th exon for the 2.4-kb mRNA. The result also shows that TPA-1 Bis sufficient to confer TPA-sensitivity on C. elegans. We are now examining tissue expression patterns of the 2.8-kb and 2.4-kb mRNAs with tpa-1 -lacZfusions to ask whether there are any differences in the distribution of these two mRNA