Effects of HMGN1 on chromatin structure and SWI/SNF-mediated chromatin remodeling.
The dynamic modulation of chromatin structure is determined by many factors, including enzymes that modify the core histone proteins, enzymes that remodel the structure of chromatin, and factors that bind to genomic DNA to affect its structure. Previous work indicates that the nucleosome binding family of high mobility group proteins (HMGN) facilitates the formation of a chromatin structure that is more conducive for transcription. SWI/SNF complexes are ATP-dependent chromatin remodeling enzymes that alter nucleosome structure to facilitate the binding of various regulatory proteins to chromatin. Here we examine the structural consequences of reconstituting chromatin with HMGN1 and the resulting effects on hSWI/SNF function. We demonstrate that HMGN1 decreases the sedimentation velocity of nucleosomal arrays in low ionic strength buffers but has little effect on the structure of more highly folded arrays. We further demonstrate that HMGN1 does not affect SWI/SNF-dependent chromatin remodeling on either mononucleosomes or nucleosomal arrays, indicating that SWI/SNF functions independently of HMGN1.
Hill
David A
DA
Department of Cell Biology at the University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA. david.hill@umassmed.edu
Peterson
Craig L
CL
Imbalzano
Anthony N
AN
D000255:Adenosine Triphosphate / Q000737:chemistry; D000818:Animals; D000906:Antibodies / Q000737:chemistry; D015153:Blotting, Western; D002645:Chickens; D002843:Chromatin / Q000737:chemistry*; D004247:DNA / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D024241:HMGN1 Protein / Q000737:chemistry*; D006801:Humans; D015636:Magnesium Chloride / Q000494:pharmacology; D009707:Nucleosomes / Q000737:chemistry / Q000378:metabolism; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D013997:Time Factors; D014157:Transcription Factors / Q000737:chemistry*; D014158:Transcription, Genetic
D000906:Antibodies; D002843:Chromatin; D024241:HMGN1 Protein; D009707:Nucleosomes; D014157:Transcription Factors; D015636:Magnesium Chloride; D012967:Sodium Dodecyl Sulfate; D000255:Adenosine Triphosphate; D004247:DNA