Cortex, a Drosophila gene required to complete oocyte meiosis, is a memberof the Cdc20/fizzy protein family

Mutations in cortex and grauzone cause abnormal arrest in Drosophila female meiosis. cortex was mapped to a 14 kb interval in 26F-27A by the male reco mbination mapping method. While these experiments mapped the gene accuratel y, they also illustrated some complexities of this method. Rescue results s howed that a 2.8 kb genomic fragment from this interval was able to fully r escue the cortex phenotype. The 2.8 kb rescuing fragment contains a single open reading frame. The predicted amino acid sequence indicates that cortex encodes a WD-repeat protein and is a distant member of the Cdc20 protein f amily. Results from a developmental Northern analysis showed that the corte x transcript is expressed at high levels during oogenesis and early embryog enesis. Interestingly, the meiotic metaphase-anaphase II arrest defect in e mbryos laid by cortex homozygous females resembles the mitotic metaphase-an aphase defects observed in yeast cdc20 mutants. The predicted nature of the Cortex protein, together with the observed meiotic phenotype in cortex mut ants, suggest that a similar pathway to the cdc20 dependent APC-mediated pr oteolysis pathway, which governs the metaphase-anaphase transition in mitos is, is also important in regulating oocyte meiosis, genesis (C) 2001 Wiley- Liss, Inc.