Worm Breeder's Gazette 12(4): 26 (October 1, 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.
We obtained a C. elegans genomic clone, which potentially encoded amino acids highly homologous to the C-terminus of rat G protein a(s) subunit, by using a cDNA fragment of rat Gsa as a probe (WBG 11, No 1, 33, 1989). From this clone (lEGL1-9), we subcloned a 13 kb Hind III fragment, and sequenced the hybridizing regions. The results revealed several regions encoding putative Gsa amino acid sequences. We repeatedly screened a cDNA library of Barstead and Waterston using a genomic probe but without success. Then we synthesized several oligonucleotides corresponding to the presumed exons, and used them to isolate cDNA fragments by reverse transcription of poly (A) RNA and PCR. From the sequences of these cDNAs and the genomic clone, we predict a protein of 375 amino acids as shown below. This predicted protein has amino acid identify of 66% overall, and about 90% in conserved regions, with that of rat Gsa. The homologies with Goa, Gpa-1 , Gpa-2 and Gpa-3 of C. elegans (Silva & Plasterk, J. Mol. Biol. 215. 483487,1990; Lochrie et al., Cell Regulation 2,135-154,1991) are lower (34-40%) and those with other mammalian Ga(Gi, Go, Gt) subunits are also lower(40-42%). Therefore, we conclude that gsa-1 encodes a Gsa protein of C. elegans. Recently, we have screened an embryonic cDNA library of A. Fire (WBG 12, No. 2, 16, 1992) and obtained several positive clones. They are being analyzed.
The gsa-1 gene probably consists of 8 exons and 7 introns extending over a 6kb region. It was mapped to a cosmid R06A10 near the left end of chromosome 1, by hybridization with YAC filters and with several candidate cosmid clones. In the region of genetic map which may correspond to cosmid R06A10 ,several mutations had been mapped such as bli-3 , let-362 , unc-35 , egl-30 and lin-6 .We are examining whether one of these mutations resides in gsa-1 .We are also trying to construct gsa-1 /lacZchimeric genes in several ways to probe expression pattern of gsa-1 .[See Figure]
Silva & Plasterk, J. Mol. Biol. 215. 483487,1990.
Lochrie et al., Cell Regulation 2,135-154,1991.
Fire, WBG 12, No. 2, 16, 1992.