The epigenetic control of E-box and Myc-dependent chromatin modifications regulate the licensing of lamin B2 origin during cell cycle
File(s)Nucl. Acids Res.-2012-Swarnalatha-9021-35.pdf (2.66 MB)
Published version
Author(s)
Swarnalatha, M
Singh, AK
Kumar, V
Type
Journal Article
Abstract
Recent genome-wide mapping of the mammalian replication origins has suggested the role of transcriptional regulatory elements in origin activation. However, the nature of chromatin modifications associated with such trans-factors or epigenetic marks imprinted on cis-elements during the spatio-temporal regulation of replication initiation remains enigmatic. To unveil the molecular underpinnings, we studied the human lamin B2 origin that spatially overlaps with TIMM 13 promoter. We observed an early G1-specific occupancy of c-Myc that facilitated the loading of mini chromosome maintenance protein (MCM) complex during subsequent mid-G1 phase rather stimulating TIMM 13 gene expression. Investigations on the Myc-induced downstream events suggested a direct interaction between c-Myc and histone methyltransferase mixed-lineage leukemia 1 that imparted histone H3K4me3 mark essential for both recruitment of acetylase complex HBO1 and hyperacetylation of histone H4. Contemporaneously, the nucleosome remodeling promoted the loading of MCM proteins at the origin. These chromatin modifications were under the tight control of active demethylation of E-box as evident from methylation profiling. The active demethylation was mediated by the Ten-eleven translocation (TET)-thymine DNA glycosylase-base excision repair (BER) pathway, which facilitated spatio-temporal occupancy of Myc. Intriguingly, the genome-wide 43% occurrence of E-box among the human origins could support our hypothesis that epigenetic control of E-box could be a molecular switch for the licensing of early replicating origins.
Date Issued
2012-07-05
Date Acceptance
2012-05-31
Citation
Nucleic Acids Research, 2012, 40 (18), pp.9021-9035
ISSN
0305-1048
Publisher
Oxford University Press
Start Page
9021
End Page
9035
Journal / Book Title
Nucleic Acids Research
Volume
40
Issue
18
Copyright Statement
© The Author(s) 2012. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Subjects
Developmental Biology
05 Environmental Sciences
06 Biological Sciences
08 Information And Computing Sciences
Publication Status
Published