Functional role of extranucleosomal DNA and the entry site of the nucleosome in chromatin remodeling by ISW2.
A minimal amount of extranucleosomal DNA was required for nucleosome mobilization by ISW2 as shown by using a photochemical histone mapping approach to analyze nucleosome movement on a set of nucleosomes with varied lengths of extranucleosomal DNA. ISW2 was ineffective in repositioning or mobilizing nucleosomes with <or=20 bp of extranucleosomal DNA. In addition, ISW2 was able to slide nucleosomes to within only 10 to 13 bp of the edge of DNA fragments. The nucleosome mobilization was promoted by extranucleosomal single-stranded DNA with modest strand preference. Gaps (10 bp) just inside the nucleosome and in the extranucleosomal DNA showed that the transfer of torsional strain (twist) into the nucleosomal DNA region was not required for mobilizing nucleosomes. However, indications are that the extranucleosomal DNA immediately adjacent to the nucleosome has an important role in the initial stage of nucleosome movement by ISW2.
Zofall
Martin
M
Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901-4413, USA.
Persinger
Jim
J
Bartholomew
Blaine
B
D000251:Adenosine Triphosphatases / Q000235:genetics* / Q000378:metabolism*; D042002:Chromatin Assembly and Disassembly / Q000235:genetics / Q000502:physiology; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D009707:Nucleosomes / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism*; D013816:Thermodynamics
D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D009707:Nucleosomes; D029701:Saccharomyces cerevisiae Proteins; D000251:Adenosine Triphosphatases; C470546:ISW1 protein, S cerevisiae