MUTATIONS AFFECTING CHROMATID SEPARATION IN DROSOPHILA - THE FIZZY METAPHASE ARREST PERSISTS IN PIMPLES FIZZY AND FIZZY 3 ROWS DOUBLE MUTANTS

Mutations in the Drosophila genes three rows (thr), fizzy (fzy), and p imples (pim) block chromosome segregation in mitosis. fzy mutations al so block cyclin degradation and affected cells become permanently arre sted in metaphase. Mutations in pim and thr prevent chromatid separati on but proteolysis of mitotic cyclins occurs normally and cells leave mitosis. Since it has been shown that active cdc2 is required to maint ain the arrest seen in fzy embryos we wished to determine if pim(+) an d thr(+) were also required. By constructing double-mutant combination s of the three genes we have established that the fzy arrest persists in the absence of either pim or thr and that there is no synergistic i nteraction between pim and thr. (C) 1997 Academic Press