The
mel-26 (maternal-effect lethal) gene of Caenorhabditis elegans acts genetically as a post-meiotic negative regulator of
mei-1, an oocyte meiosis-specific gene. Failure of
mel-26 to inactivate
mei-1 following meiosis results in ectopic assembly of MEI-1 into mitotic spindles, which leads to defective cell division. We have identified two dominant-negative and eight loss-of-function alleles of
mel-26. To better understand mechanisms used to maintain meiosis-specific gene activity, and
mei-1 regulation specifically, the cloning and characterization of the
mel-26 gene was undertaken. Transformation rescue of
sb4, a loss-of-function allele of
mel-26, was obtained with the cosmid ZK858, and was subsequently narrowed down to a 6.5 kb fragment. This fragment was used to screen Irene Schauer's embryo-enriched cDNA library, from which 3 overlapping clones were isolated. The complete cDNA and genomic DNA sequence has been obtained. Analysis of the predicted peptide sequences reveals that MEL-26 is most closely related to predicted C. elegans ORFs T16H12.5, C50C3.8 and C07D10.2. There is also limited homology to the BTB domain, a motif suggested to play a role in protein-protein interactions. Bacterially expressed MEL-26 is currently being used to generate antibodies, which will be used in indirect immunofluorescent microscopy and Western Blot experiments. Also in progress is identification of the molecular basis of each
mel-26 allele. Results of these experiments will be presented.