Worm Breeder's Gazette 13(5): 67 (February 1, 1995)
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.
Fundamental Research Laboratories, NEC Corporation 34 Miyukigaoka, Tsukuba, Ibaraki 305 JAPAN The emb-5 gene is required for the correct timing of division ofgut precursor cells during gastrulation in C. elegans. A protein database search indicates that the predicted emb-5 gene product has no significant similarity to any other known proteinsexcept for the Saccharomyces cerevisiae nuclear protein SPT6, which has been shown to affect the transcription of various genes. To investigate the universality and general importance implicated bythe emb-5 gene product in biological systems, we have begun to search for emb-5 homologs in other animals. First, we looked for an emb-5 homolog in C. briggsae, a close kin to C. elegans. Genomic DNA from C. briggsae was digested with several restriction enzymes and hybridized in Southern blots with a C-terminal fragment(about 1.7 kb) of emb-5 cDNA as a probe. We detected a 2.5-kb positive fragment in ClaI digested DNA and cloned it into pBluescript KS(- ). Sequencing of this fragment has revealed that it is a C-terminus of an emb-5 homolog. Next, we constructed a C. briggsae genomic DNA library of Sau3AI partially digested DNA cloned in lambda DASH II vector, and obtained the clones that hybridyzed to the above 2.5-kb ClaI fragment. Finally, we sequenced the entire emb-5 homolog DNA by analyzing these clones. The predicted amino acid sequence (1521 aa) has 80% homology to that of EMB-5, although homology is 60% at the DNA level, and there exist both highly conserved and less conserved regions. The mutation site of hc61 is located in a highly conserved region. The positions of introns found in the emb-5 homolog are almost the same as in C. elegans emb-5, although the intron corresponding to the 6th one of C. elegans is missing in C. briggsae. There is little obvious identity in the lengths and sequences of corresponding introns between C. briggsae and C. elegans. We are trying to rescue the hc61 mutation of C. elegans by injecting C. briggsae DNA.