Identification of HsORC4, a Member of the Human Origin of Replication Recognition Complex*
- From the Division of Molecular Oncology, Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts 02115
Abstract
A new member of human origin recognition complex (ORC) has been cloned and identified as the human homologue ofSaccharomyces cerevisiae ORC4. HsORC4 is a 45-kDa protein encoded by a 2.2-kilobase mRNA whose amino acid sequence is 29% identical to ScORC4. HsORC4 has a putative nucleotide triphosphate binding motif that is not seen in ScORC4. HsORC4P also reveals an unsuspected homology to the ORC1-Cdc18 family of proteins. HsORC4 mRNA expression and protein levels remain constant through the cell cycle. HsORC4P is coimmunoprecipitated from cell extracts with another subunit of human ORC, HsORC2P, consistent with it being a part of the putative human origin recognition complex.
Footnotes
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↵* This work was supported by National Institutes of Health Grant CA60499.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
The nucleotide sequence(s) reported in this paper has been submitted to the GenBank™/EMBL Data Bank with accession number(s) AF022108.
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↵‡ Supported by a grant from the Massachusetts Department of Public Health.
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↵§ Supported by a career development award from the United States Army (DAMD17-94-J-4064) and to whom correspondence should be addressed. Tel.: 617-278-0468; Fax: 617-732-7449; E-mail: adutta{at}bustoff.bwh.harvard.edu.
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↵1 The abbreviations used are: ORC, origin recognition complex; EST, Expressed Sequence Tag; GST, glutathioneS-transferase.
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↵2 P. Saha, J. Chen, A. Dutta, unpublished results.
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- Received July 7, 1997.
- Revision received September 8, 1997.
