Cdc6 ATPase activity regulates ORC center dot Cdc6 stability and the selection of specific DNA sequences as origins of DNA replication

Speck, C., Stillman, B. (2007) Cdc6 ATPase activity regulates ORC center dot Cdc6 stability and the selection of specific DNA sequences as origins of DNA replication. Journal of Biological Chemistry, 282 (16). pp. 11705-11714. ISSN 0021-9258

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URL: http://www.ncbi.nlm.nih.gov/pubmed/17314092
DOI: 10.1074/jbc.M700399200

Abstract

DNA replication, as with all macromolecular synthesis steps, is controlled in part at the level of initiation. Although the origin recognition complex ( ORC) binds to origins of DNA replication, it does not solely determine their location. To initiate DNA replication ORC requires Cdc6 to target initiation to specific DNA sequences in chromosomes and with Cdt1 loads the ring-shaped mini-chromosome maintenance ( MCM) 2-7 DNA helicase component onto DNA. ORC and Cdc6 combine to form a ring-shaped complex that contains six AAA(+) subunits. ORC and Cdc6 ATPase mutants are defective in MCM loading, and ORC ATPase mutants have reduced activity in ORC.Cdc6.DNA complex formation. Here we analyzed the role of the Cdc6 ATPase on ORC.Cdc6 complex stability in the presence or absence of specific DNA sequences. Cdc6 ATPase is activated by ORC, regulates ORC.Cdc6 complex stability, and is suppressed by origin DNA. Mutations in the conserved origin A element, and to a lesser extent mutations in the B1 and B2 elements, induce Cdc6 ATPase activity and prevent stable ORC.Cdc6 formation. By analyzing ORC.Cdc6 complex stability on various DNAs, we demonstrated that specific DNA sequences control the rate of Cdc6 ATPase, which in turn controls the rate of Cdc6 dissociation from the ORC.Cdc6.DNA complex. We propose a mechanism explaining how Cdc6 ATPase activity promotes origin DNA sequence specificity; on DNA that lacks origin activity, Cdc6 ATPase promotes dissociation of Cdc6, whereas origin DNA down-regulates Cdc6 ATPase resulting in a stable ORC.Cdc6.DNA complex, which can then promote MCM loading. This model has relevance for origin specificity in higher eukaryotes.

Item Type: Paper
Uncontrolled Keywords: WALKER-A MOTIF RECOGNITION COMPLEX BUDDING YEAST S-PHASE SACCHAROMYCES-CEREVISIAE FISSION YEAST ESCHERICHIA-COLI IN-VITRO CHROMOSOMAL ORIGIN BINDING-SITES
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > Cdc6
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > DNA replication
bioinformatics > genomics and proteomics > annotation > sequence annotation
bioinformatics > genomics and proteomics > Mapping and Rendering > Sequence Rendering
CSHL Authors:
Communities: CSHL labs > Stillman lab
Highlight: Stillman, Bruce W.
Depositing User: CSHL Librarian
Date Deposited: 02 Nov 2011 16:51
Last Modified: 20 Jun 2017 16:45
PMCID: PMC3033201
Related URLs:
URI: http://repository.cshl.edu/id/eprint/23144

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