Format

Send to

Choose Destination
Biochim Biophys Acta Gene Regul Mech. 2019 Apr;1862(4):486-492. doi: 10.1016/j.bbagrm.2019.02.002. Epub 2019 Feb 27.

The bZIP mutant CEBPB (V285A) has sequence specific DNA binding propensities similar to CREB1.

Author information

1
Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, United States of America.
2
Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, United States of America.
3
Center for Autoimmune Genomics and Etiology, Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, United States of America; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, United States of America.
4
Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, United States of America. Electronic address: vinsonc@mail.nih.gov.

Abstract

The bZIP homodimers CEBPB and CREB1 bind DNA containing methylated cytosines differently. CREB1 binds stronger to the C/EBP half-site GCAA when the cytosine is methylated. For CEBPB, methylation of the same cytosine does not affect DNA binding. The X-ray structure of CREB1 binding the half site GTCA identifies an alanine in the DNA binding region interacting with the methyl group of T, structurally analogous to the methyl group of methylated C. This alanine is replaced with a valine in CEBPB. To explore the contribution of this amino acid to binding with methylated cytosine of the GCAA half-site, we made the reciprocal mutants CEBPB(V285A) and CREB1(A297V) and used protein binding microarrays (PBM) to examine binding to four types of double-stranded DNA (dsDNA): 1) DNA with cytosine in both strands (DNA(C|C)), 2) DNA with 5-methylcytosine (M) in one strand and cytosine in the second strand (DNA(M|C)), 3) DNA with 5-hydroxymethylcytosine (H) in one strand and cytosine in the second strand (DNA(H|C)), and 4) DNA with both cytosines in all CG dinucleotides containing 5-methylcytosine (DNA(5mCG)). When binding to DNA(C|C), CEBPB (V285A) preferentially binds the CRE consensus motif (TGACGTCA), similar to CREB1. The reciprocal mutant, CREB1(A297V) binds DNA with some similarity to CEBPB, with strongest binding to the methylated PAR site 8-mer TTACGTAA. These data demonstrate that V285 residue inhibits CEBPB binding to methylated cytosine of the GCAA half-site.

PMID:
30825655
DOI:
10.1016/j.bbagrm.2019.02.002
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center