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Cell cycle‐dependent binding of replication and transcription proteins to the human DBF4 ori
Author(s) -
Romero Julia,
Lee Hoyun
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.483.1
Subject(s) - origin recognition complex , pre replication complex , control of chromosome duplication , biology , replication timing , dna replication factor cdt1 , dna replication , licensing factor , eukaryotic dna replication , genetics , replication factor c , origin of replication , chromatin immunoprecipitation , microbiology and biotechnology , promoter , gene , gene expression
We have previously identified an origin of DNA replication (ori) at the transcriptional promoter of the human DBF4 gene. Using a novel replication initiation point (RIP) mapping procedure, we have shown that replication from the DBF4 ori initiates from multiple potential start‐sites which are distributed within two zones separated by ~400‐bp on the complementary DNA strands. Initiation from the two replication zones occurs sequentially, which we termed asymmetric bidirectional replication (ABR). Using chromatin immunoprecipitation (ChIP) assays we have studied protein‐DNA interactions at the DBF4 ori during cell cycle progression. Our data show that the origin recognition complex (ORC) binds to both replication zones simultaneously during late G1. However, during the G1/S transition and following S‐phase entry, ORC is sequentially released from its binding sites, mirroring the ABR pattern. ChIP data also suggests that binding of the Sp1 transcription factor and replication proteins to the DBF4 locus is mutually exclusive. This data is consistent with the idea that transcription and replication are inversely correlated at the DBF4 locus. Overall, this study provides new insight into how DNA replication and transcriptional activities are regulated in a concerted manner at ori/promoters in mammalian cells. This work was supported by grants from the Canadian Institutes of Health Research to H.L.