Strand interruptions confer strand preference during intracellular correction of a plasmid-borne mismatch in Saccharomyces cerevisiae.
Site-directed mutagenesis was used to construct yeast centromere plasmids in which a strand nick or gap could be placed 5' or 3', on either strand, to a reporter gene (SUP4-o) carrying defined base mismatches. The plasmids were then transformed into yeast cells and the direction and efficiency of mismatch repair were assayed by scoring colouring of the transformant colonies. Strands that were nicked were consistently corrected more often than intact strands, but the effect was very small. However, placement of a small gap at the same positions as the nicks resulted in a marked increase in selection for the gapped strand and an enhanced efficiency of mismatch repair. Both the preference for the gapped strand and correction of the mismatch were offset by deletion of the mismatch repair gene PMS1. Together, the results suggest that strand interruptions can direct intracellular mismatch correction of plasmid-borne base mispairs in yeast.
Yang
Y
Y
Department of Pathology, Vancouver Hospital at the Health Sciences Centre, 855 West 12th Avenue, Vancouver, British Columbia, V5Z 1M9, Canada.
Kang
X
X
Kohalmi
L
L
Karthikeyan
R
R
Kunz
B A
BA
D020137:Base Pair Mismatch / Q000235:genetics*; D004249:DNA Damage / Q000235:genetics; D004260:DNA Repair / Q000235:genetics*; D015245:Deoxyribonuclease BamHI / Q000235:genetics; D015246:Deoxyribonuclease EcoRI / Q000235:genetics; D015252:Deoxyribonucleases, Type II Site-Specific / Q000235:genetics; D005821:Genetic Techniques; D016297:Mutagenesis, Site-Directed; D009692:Nucleic Acid Heteroduplexes; D010641:Phenotype; D010957:Plasmids / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics*
D009692:Nucleic Acid Heteroduplexes; D015245:Deoxyribonuclease BamHI; D015246:Deoxyribonuclease EcoRI; C034510:CTCGAG-specific type II deoxyribonucleases; D015252:Deoxyribonucleases, Type II Site-Specific