Worm Breeder's Gazette 11(3): 23
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.
lin-3 is necessary for vulval induction. Animals with lowered levels of lin-3 activity have lowered or absent induction of the vulva while animals with no lin-3 function die before vulval induction would occur. Epistasis experiments between lin-3 and multivulva mutations suggest that lin-3 acts early in the pathway of vulval induction. For these reasons we are cloning lin-3.A transposon induced allele of lin- 3 called sy91 was isolated from the mutator strain RW7096. A novel Tc1 insertion present in sy91 strains has been identified. This insertion cosegregates with the Vul phenotype of sy91 in 27 recombination events occurring in the 0.6 mu interval between the flanking markers mec-3 and dpy-20. The sequence flanking this Tc1 insertion was amplified using inverse PCR and used to identify the Tclin-3 contig (fig. 1). A second lin-3 RFLP was identified by probing genomic southerns of 10 different lin-3 alleles with lambdaPS#001. This RFLP is a novel EcoRV site found in the allele n1058 and is located 2.5kb from the sy91 insertion site (fig. 2). We have not yet conclusively identified the lin-3 transcription unit. Clones spanning the contig were probed with total first stand [32P]- cDNA (Reverse Northern). These experiments identified two regions of the contig which are transcribed. The closest transcribed region lies within several hundred base pairs of the n1058 RFLP and extends toward the end of lambdaPS#001 (fig. 2). The other transcribed region is within the overlap of F17G6 and K08G5 and is at least 10 kb from the sy91 RFLP (not shown). These two regions have not been proven to be different transcription units and it is also possible that other transcription units are present in the contig but have not yet been detected. We are currently trying to identify the location of lin-3 by microinjecting genomic clones spanning the contig to see if any of these clones can rescue lin-3. If no clones are able to rescue lin-3 we will try to extend the contig. We are also characterizing the region of the Tclin-3 contig around the sy91 and n1058 RFLPs. [See Figure 1]