The 55 kd regulatory subunit of Drosophila protein phosphatase 2A is required for anaphase

The gene encoding the Drosophila protein phosphatase 2A 55 kd regulatory subunit (PR55) is located at 85F and directs the synthesis of differentially spliced transcripts. Maternal RNAs are present at very high levels in early embryos and decline around cellularization. Zygotic transcripts are present mainly in the developing embryonic nervous system and gonads. Transcripts are uniformly distributed in third instar larval discs and testes and at lower levels in the proliferative centers of the brain. Mutations in abnormal anaphase resolution (aar) are rescued by the wild-type gene for PR55. aar mutants display intact lagging chromatids that have undergone separation from their sisters, but that remain at the position formerly occupied by the metaphase plate, as well as anaphase figures that show bridging chromatin having two centromeric regions.