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DNA synthesis at individual replication forks requires the essential initiation factor Cdc45p
Author(s) -
Tercero José Antonio,
Labib Karim,
Diffley John F.X.
Publication year - 2000
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/19.9.2082
Subject(s) - biology , pre replication complex , origin recognition complex , replication factor c , control of chromosome duplication , dna replication , dna replication factor cdt1 , licensing factor , eukaryotic dna replication , s phase , minichromosome maintenance , dna re replication , microbiology and biotechnology , genetics , semiconservative replication , ter protein , dna
Cdc45p assembles at replication origins before initia tion and is required for origin firing in Saccharomyces cerevisiae . A heat‐inducible cdc45 degron mutant was constructed that promotes rapid degradation of Cdc45p at the restrictive temperature. Consistent with a role in initiation, loss of Cdc45p in G 1 prevents all detectable DNA replication without preventing subsequent entry into mitosis. Loss of Cdc45p activity during S‐phase blocks S‐phase completion but not activation of replication checkpoints. Using density substitution, we show that after allowing replication fork establishment, Cdc45p inactivation prevents the subsequent progression of individual replication forks. This provides the first direct functional evidence that Cdc45p plays an essential role during elongation. Thus, like the large T antigen in SV40 replication, Cdc45p plays a central role in both initiation and elongation phases of chromosomal DNA replication.