ISOLATION OF 2 GENES THAT AFFECT MITOTIC CHROMOSOME TRANSMISSION IN SACCHAROMYCES-CEREVISIAE

Two DNA sequences that reduce mitotix fidelity of chromsome transmission have been identified: MIF1 and MIF2. MIF2 is a unique sequence located on the right arm of chromsome XII that stimulates loss and recombination for both chromosomes V and VII when present in a high copy number plasmid. MIF1 is not essential for cell division but is necessary for the normal fidelity of chromosome transmission. MIF2 is a unique sequence located 15 cM distal to HIS6 on chromosome IX that induce a high frequency of chromosme VII loss and a lower frequency of chromosome V loss when present in high copy number; it has no effect on mitotic recombination. Disruption of the genomic MIF2 locus was lethal and cells lacking this function arrested division with a terminal phenotype characteristic of a block in DNA replication or nuclear division.