Y. Saka et M. Yanagida, FISSION YEAST CUT5-PHASE ONSET AND M-PHASE RESTRAINT, IS IDENTICAL TOTHE RADIATION-DAMAGE REPAIR GENE RAD4+(, REQUIRED FOR S), Cell, 74(2), 1993, pp. 383-393
Fission yeast cut5 mutants cause cytokinesis in the absence of normal
nuclear division. We show here that cut5+ is required for both the ons
et of S phase and the restraint of M phase before the completion of S
phase. The primary defects in cut5 mutants occur prior to S phase, but
cells suffer lethal damage during M phase. Mitosis and cytokinesis oc
cur in the presence of hydroxyurea or in the double mutant cdc10-cut5
(the cdc10 mutation alone blocks progression from G1 to S). Gene cloni
ng shows that cut5+ is identical to the fission yeast rad4+ gene, whic
h is similar to human XRCC1. The rad4+/cut5+ gene is unique in its pos
itive role for replication/repair and in its negative role for mitosis
/cytokinesis. We propose a single/twin chromatid marking model for rad
4+/cut5+ function in cell cycle control.