Worm Breeder's Gazette 13(2): 58 (February 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.
We are analyzing genes concerned on the signal transduction pathway in the excitation contraction coupling of Caenorhabditis elegans. Ryanodine receptor is a calcium release channel which was first cloned from rabbit skeletal muscle, forming homo-tetrameric complexes on sarcoplasmic reticulum. Several experiments showed its existence in neurons and epithelial cells, suggesting that the ryanodine receptor is not restricted in muscle cells, but is widely distributed in other cells which undergoes calcium signaling. In mammals, the ryanodine receptor is well characterized and three types of cDNAs are cloned. In C. elegans, we can know what kinds of molecule is interacted with ryanodine receptor mediated signaling by using genetical approaches. At the first, we have cloned a cDNA fragment of C. elegans ryanodine receptor which encoded C-terminal 526 amino acids. Deduced amino acid sequence was 44% homologous to those of mammalian ryanodine receptors. The ryanodine receptor gene, ryr-1 of C. elegans was mapped on the central left of chromosome V, and we concluded that ryr-1 was the only gene encoding the ryanodine receptor of the animal. Unfortunately no corresponding mutant is isolated in this map region. We sequenced the genome DNA of ryr-1 mainly from the cosmid clone M04C11 ,and completed the genome structure of the gene. It extended about 30kb-long and consisted of at least 46 exons, encoding 5,068 amino acid residues. The amino acid sequence of the C. elegans ryanodine receptor was most homologous to the cardiac type of mammals, and two EF-hand motifs in a cytoplasmic loop between the transmembrane segment M2 and M3 (by M1 ~M10model) might be responsible for the CICR (calcium induced calcium release) of ryanodine receptor. Expression patterns of ryr-1 /lacZfusion genes showed that ryr-1 was widely expressed in many cells. More than 840bp of 5'-UTR was required for expressing the hybrid plasmid. We are interested in the possibility of an enhancer activity in the first intron of 3.9kb and trans-splicing with SL1 leader.