Résumé
Five cyclin-like genes,
cig1, cig2/cyc17, mcs2, puc1 and
cdc13, have been discovered in
S. pombe to date. It is not yet clear what their functions are or even whether they are all involved with control of the cell cycle. Conflicting data for
cig1 and
cig2/cyc17 have obscured analysis of their function and
cig1 remains largely uncharacterized, although clues to the role of
cig2/cyc17 have emerged. There is genetic data available for the more distant cyclin homologue
mcs2, which has an essential although as yet unspecified role.
Puc1 may be involved in regulation of exit from the cell cycle. The first cyclin to be discovered, and the best understood, is
cdc13 which with
cdc2 promotes mitosis. Studies of the roles of
cdc2 and
cdc13 in the overall ordering of the cell cycle suggest that
cdc13 and probably other cyclins are key regulators, maintaining the order of S phase and mitosis during the cell cycle.