Characterization of Ce-atl-1, an ATM-like gene from Caenorhabditis elegans

An ATM-like gene was identified in the genome of Caenorhabditis elegans. Th e putative product of the gene, termed Ce-atl-1 (C. elegans ATM-like 1) con sists of 2514 amino acid residues. The C-terminal sequence, which contains a PI-3 kinase-like domain, showed good homology with the products of the ge ne MEC1/ESR1 from budding yeast, the rad3(+) gene of fission yeast and mamm alian A TR (ataxia-telangiectasia and rad3(+) related) genes. The results o f RNA-mediated interference indicated that the major phenotype associated w ith repression of Ce-atl-1 was lethality (approximately 50-80%) during earl y embryogenesis. Among the surviving progeny, males (XO animals) arose at a high frequency (2-30%). In addition, 5% of oocyte chromosomes demonstrated aneuploidy due to a defect in pre-meiotic chromosomal segregation. Gene ex pression analyses indicated that Ce-atl-1 mRNA was expressed in all larval stages and that its level increased about fivefold in the adult stage. The adult expression level was de creased in the glp-4 mutant, which is defecti ve in germ line proliferation. Ce-atl-1 was strongly expressed in both the mitotic and meiotic cells of adult gonads. In summary, Ce-atl-1 appears to be important for early embryogenesis, and loss of its function results in a defect in chromosome segregation, similar to what has been observed for AT -related proteins.