Investigation of the Interaction of Human Origin Recognition Complex Subunit 1 with G-Quadruplex DNAs of Human <i>c-myc</i> Promoter and Telomere Regions
Origin recognition complex (ORC) binds to replication origins in eukaryotic DNAs and plays an important role in replication. Although yeast ORC is known to sequence-specifically bind to a replication origin, how human ORC recognizes a replication origin remains unknown. Previous genome-wide studies...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2021-03-01
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| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/22/7/3481 |
| Summary: | Origin recognition complex (ORC) binds to replication origins in eukaryotic DNAs and plays an important role in replication. Although yeast ORC is known to sequence-specifically bind to a replication origin, how human ORC recognizes a replication origin remains unknown. Previous genome-wide studies revealed that guanine (G)-rich sequences, potentially forming G-quadruplex (G4) structures, are present in most replication origins in human cells. We previously suggested that the region comprising residues 413–511 of human ORC subunit 1, hORC1<sup>413–511</sup>, binds preferentially to G-rich DNAs, which form a G4 structure in the absence of hORC1<sup>413–511</sup>. Here, we investigated the interaction of hORC1<sup>413-511</sup> with various G-rich DNAs derived from human <i>c-myc</i> promoter and telomere regions. Fluorescence anisotropy revealed that hORC1<sup>413–511</sup> binds preferentially to DNAs that have G4 structures over ones having double-stranded structures. Importantly, circular dichroism (CD) and nuclear magnetic resonance (NMR) showed that those G-rich DNAs retain the G4 structures even after binding with hORC1<sup>413–511</sup>. NMR chemical shift perturbation analyses revealed that the external G-tetrad planes of the G4 structures are the primary binding sites for hORC1<sup>413–511</sup>. The present study suggests that human ORC1 may recognize replication origins through the G4 structure. |
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| ISSN: | 1661-6596 1422-0067 |