ANALYSIS OF MAINTENANCE OF REDUNDANT GENE TIC STRUCTURES IN THE YEASTSACCHAROMYCES-CEREVISIAE - EFFECTS OF MUTATIONS CDC28SRM AND SRM1

The effects of nuclear gene mutations cdc28-srm and srm1 on the mainte nance of various recombinant facultative genetic structures (FGSs) in Saccharomyces cerevisiae were studied. These structures are ARS1 TRP1 mini-coils, noncentromeric circular plasmids containing various ARS el ements, and extended linear yeast artificial chromosomes (YAC). These mutations led to an increase in the mitotic stability of some of the F GS tested and the disturbed maintenance of the others. Mutation srm1 i mposed a stabilizing effect on the maintenance of various recombinant FGSs with ARS chromosomal elements. Mutation cdc28-srm destabilized th e maintenance of only those recombinant FGS that shared full or detect able homology with sequences of the nuclear genome of the yeast cell.