Worm Breeder's Gazette 12(3): 48 (June 15, 1992)

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.

Sequence Analysis of Dominant and Recessive her-l Mutations

Caroline Chamblin, Carol Trent

Department of Biology, Western Washington University, Bellingham WA

Two her-1 transcripts have been previously identified: a 0.8 kb transcript found at high levels in XO and very low levels in XX animals and a 1.2 kb transcript observed at low levels in XO animals only. The dominant her-1 mutations n695 and y101 ,which cause variable masculinization of XX animals, result in increased levels of both her-1 transcripts in XX embryos. We have cloned and sequenced the her-1 genes from partial genomic libraries of these mutant strains. Both strains have a G --> A transition a few base pairs upstream of the cap site for the 1.2 kb transcript. That the two strains have the same mutation was not expected since y101 shows a more extreme sexual transformation than n695 .The mutation has been confirmed in both strains by direct sequencing of PCR products made from genomic DNA. We have sequenced the exons for each mutant gene and about l.5kb upstream of the transcription start site, but have not observed an additional mutation in either strain.

We are in the process of sequencing the recessive her-1 alleles that result in the preferential loss of the 1.2kb transcript: ct50 n695 , e1519 , e1574 , n827 n695 and y10 .In such strains, the 1.2kb transcript cannot be detected by Northern analysis, but the 0.8kb transcript is present at approximately wild-type levels. The ct50 n695 mutation, used originally to isolate her-1 sequences, results from a Tc1 insert 55 bp upstream of the cap site for the 1.2 kb transcript. We are analyzing the other four mutant alleles by direct sequencing of DNA generated by PCR amplification of specific regions of the her-1 gene. The loss of the larger transcript in e1519 is due to a splicing defect resulting from a G -->A transition mutation in the first base of intron #1. Work is still in progress on the other three alleles.