ISSN:
1617-4623
Keywords:
Key words Fission yeast
;
PCNA mutants
;
cdc phenotype
;
DNA damage sensitivity
;
Cold sensitivity
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Twenty-eight site-directed mutations were introduced into the fission yeast gene (pcn1 +) that encodes proliferating cell nuclear antigen (PCNA) and their in vivo effects analyzed in a strain with a null pcn1 background. Mutants defective in enhancing processivity of DNA polymerase δ have previously been identified. In this study, we assessed all of the mutants for their sensitivities to temperature, hydroxyurea, UV irradiation and methyl methanesulfonate (MMS), and specific mutants were also tested for sensitivity to γ irradiation. One cold-sensitive allele, pcn1-3, was characterized in detail. This mutant had a recessive cold-sensitive cdc phenotype and showed sensitivity to hydroxyurea, UV, and γ irradiation. At the non-permissive temperature pcn1-3 protein was able to form homotrimers in solution and showed increased stimulation of both synthetic activity and processivity of DNA polymerase δ relative to the wild-type Pcn1+ protein. Epistasis analyses indicated that pcn1-3 is defective in the repair pathway involving rad2 + but not defective in the classical nucleotide excision repair pathway involving rad13 + . Furthermore, pcn1-3 is either synthetically or conditionally lethal in null checkpoint rad backgrounds and displays a mitotic catastrophe phenotype in these backgrounds. A model for how pcn1-3 defects may affect DNA repair and replication is presented.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s004380050676
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