Open AccessSingle and double box HMGB proteins differentially destabilize nucleosomes
Author(s) -
Micah J. McCauley,
Ran Huo,
Nicole A. Becker,
Molly Nelson Holte,
Uma M. Muthurajan,
Ioulia Rouzina,
Karolin Luger,
L. James Maher,
N. E. Israeloff,
Mark C. Williams
Publication year - 2018
Publication title -
nucleic acids research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 9.008
H-Index - 537
eISSN - 1362-4954
pISSN - 0305-1048
DOI - 10.1093/nar/gky1119
Subject(s) - nucleosome , euchromatin , biology , chromatin , high mobility group , histone , dna , microbiology and biotechnology , dna repair , genetics , gene , heterochromatin
Nucleosome disruption plays a key role in many nuclear processes including transcription, DNA repair and recombination. Here we combine atomic force microscopy (AFM) and optical tweezers (OT) experiments to show that high mobility group B (HMGB) proteins strongly disrupt nucleosomes, revealing a new mechanism for regulation of chromatin accessibility. We find that both the double box yeast Hmo1 and the single box yeast Nhp6A display strong binding preferences for nucleosomes over linker DNA, and both HMGB proteins destabilize and unwind DNA from the H2A-H2B dimers. However, unlike Nhp6A, Hmo1 also releases half of the DNA held by the (H3-H4)2 tetramer. This difference in nucleosome destabilization may explain why Nhp6A and Hmo1 function at different genomic sites. Hmo1 is enriched at highly transcribed ribosomal genes, known to be depleted of histones. In contrast, Nhp6A is found across euchromatin, pointing to a significant difference in cellular function.