The Anaphase Promoting Complex (APC) is a multi-subunit E3 ubiquitin ligase that promotes the metaphase-to-anaphase transition during meiotic and mitotic divisions. Temperature-sensitive (ts) mutants in
mat-1,
mat-2,
mat-3,
emb-27, and
emb-30 arrest as 1-cell embryos, stuck in metaphase of meiosis I. These five genes code for five subunits of the APC. The ts alleles of
emb-1 have grabbed our attention because their arrest phenotype is indistinguishable from the APC mutants. Furthermore, genetic doubles constructed between
emb-1(
hc62) and the APC mutants cannot be maintained at the permissive temperature, a common feature of any APC double mutant. Additionally, suppressors that suppress the APC mutants (Stein et al., 2007) also suppress
emb-1. What is EMB-1 you may ask? We mapped
emb-1 to a tiny interval on LG III and used RNAi to phenocopy the 1-cell arrest phenotype. Rescue and sequencing confirmed that
emb-1 codes for a novel protein with no known homologies outside of Caenorhabditis species. Localization studies are underway. We propose that EMB-1 is a novel subunit or regulator of the APC in C. elegans.