Worm Breeder's Gazette 13(3): 49 (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.
In the previous gazette (WBG, 13 # 2: 88), we have reported cloning of the cej-1 (cell junction - 1 ) gene by directly screening the C. elegans cDNA expression library with a McAb T4192 raised against the mouse 220 kd protein homologous to the intracellular tight junction proteins from a variety of organisms from Drosophila to humans (Itoh et al., JCB, 1993). Sequencing of the cej-1 cDNA and the genomic sequence data obtained from the nematode sequencing consortium has revealed a novel protein of 584 amino acids encoded by four exons and interrupted by three small introns (52, 46, and 47 bp, respectively). Counting + 1 for A in the ATG of the initiation codon, the CAAT box is at -236 (-236 to -239), the TATAA box is upstream at -716 (-716 to -720), and the poly-adenylation signal is 111 nucleotides downstream of the stop codon.
There is apparently no strong homology to any known protein in various data bases corresponding to the CEJ-1 protein; however, there are stretches of threonine residues throughout the primary sequence. For example there are ten threonine dipeptides, 16 threonine tripeptides and one threonine tetrapeptide in the CEJ-1 protein. Such poly-T motifs have also been observed in some other proteins but their physiological function has not been elucidated. An interesting aspect of the cej-1 mRNA expression (Northern blot analysis), during the nematode development is its high expression during embryogenesis, a total disappearance during the larval L1 and L2 stages and a reappearance during late larval and adult stages. We are in the process of studying the temporal and spatial expression of the cej-1 gene by in situ hybridization technique and using a cej-l::lacZ construct to study the cellular distribution of the CEJ-1 protein during development. We are also interested in obtaining Tc1 induced mutations in the cej-1 locus from the pool of such Tc1 induced mutants (R. Plasterk and colleagues), using the Tc1 and cej-1 sequence based primers. We thank members of the nematode genome sequencing consortium for their kind assistance in this project.