Worm Breeder's Gazette 13(3): 56 (June 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.
Tropomyosin is a component of thin filaments in muscle and mediates calcium signal from troponin complex to actin. The tropomyosin gene of C. elegans, tmy-1 located on the right end of chromosome I was constructed with 14 exons expanding 14kb and encoded three isoforms (CETMI, CETMII and CETMIII). Deduced amino acid sequences; 284 indicate that two were muscle types (CETMI and CETMII) that were transcribed under the control of the identical 5'noncoding region. Comparison of genomic and cDNA shows that CETMIII; 235 amino acids was transcribed from the third intron. Two of them encode muscle type which only had different 27 amino acids of C-terminus. Although any cosmid and phage library clones did not contained the genomic DNA fragment, the tmy- 1 gene locates on YAC clones; Y68B7 and Y38D6 beside unc-54 ,myosin heavy chain gene on LG I of the chromosome.
Micro injection experiment of tmy-1 /lac-zfusion plasmid containing 818 bp of 5'non-coding sequence and 27 bp of the exon la confirmed the result that CETMI and CETMII sharing the identical 5'upstream sequence expressed in the body wall, the anal, the vulva and the male sex muscle. The promoter activity locates between -818 to -621 bp from the initiation codon of the gene. The tmy-1 /lacZfusion plasmid carrying an intron fragment including 3.3kb of the third intron sequence was expressed in the pharyngeal muscles. Internal deletion of 1.56 kb was no effect on the expression of CETMIII. we are determining the pharyngeal specific promoter.