Effects of HMGN1 on chromatin structure and SWI/SNF-mediated chromatin remodeling
Department of Cell Biology; Program in Molecular Medicine
Adenosine Triphosphate; Animals; Antibodies; Blotting, Western; Chickens; Chromatin; DNA; Dose-Response Relationship, Drug; Electrophoresis, Polyacrylamide Gel; HMGN1 Protein; Humans; Magnesium Chloride; Nucleosomes; Plasmids; Protein Binding; Protein Structure, Tertiary; Sodium Dodecyl Sulfate; Time Factors; Transcription Factors; Transcription, Genetic
Cell Biology | Life Sciences | Medicine and Health Sciences
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.
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Citation: J Biol Chem. 2005 Dec 16;280(50):41777-83. Epub 2005 Oct 27. Link to article on publisher's site