We have analyzed the effects of temeperature-sensitivity (ts)-conferring mutations in the Saccharomyces cerevisiae DNA polymerase I-encoding gene on cell growth, in vivo DNA synthesis, intrachromosomal gene conversion and pop-out recombination. Also, we have identified the molecular defect responsible for the ts phenotype. Two mutant alleles (cdc17-1, cdc17-2) were originally identified as cell-cycle mutations, while a third mutation (hpr3) was found during a genetic screening for mutants with a hyper-recombination phenotype. Both cdc17-2 and hpr3 cells complete one round of cell division and DNA replication after shift to nonpermissive temperature, before being arrestedas a dumbbell-shaped cells. Conversely, the cdc17-1 mutation immediately blocks growth and DNA synthesis at 37°C. No substantial difference was observed in the frequency of intrachromosomal gene conversion and pop-out recombination events, when hpr3 and cdc17-1 were compared to the previously characterized pol1-1 mutant. These two frequencies were ten- to 30-fold above wild-type level at semipermissive temperature. In each mutant, a single bp substitution, causing the replacement of Gly residues by either Asp (cdc17-1, cdc17-2) or Glu (hpr3) in yeast DNA polymerase I is responsible for the ts phenotype.
Titolo: | Nucleotide sequence and characterization of temperature-sensitive pol1 mutants of Saccharomyces cerevisiae |
Autori: | MUZI FALCONI, MARCO (Secondo) PLEVANI, PAOLO (Ultimo) |
Parole Chiave: | cloning; DNA polymerase; gene conversion; pop-out recombination; primase; recombinant DNA |
Settore Scientifico Disciplinare: | Settore BIO/11 - Biologia Molecolare |
Data di pubblicazione: | 31-mag-1990 |
Rivista: | |
Tipologia: | Article (author) |
Digital Object Identifier (DOI): | 10.1016/0378-1119(90)90444-V |
Appare nelle tipologie: | 01 - Articolo su periodico |