Open AccessEvidence for DNA Translocation by the ISWI Chromatin-Remodeling Enzyme
Author(s) -
Iestyn Whitehouse,
Chris Stockdale,
Andrew Flaus,
Mark D. Szczelkun,
Tom Owen-Hughes
Publication year - 2003
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.23.6.1935-1945.2003
Subject(s) - nucleosome , biology , translocase , chromatin remodeling , chromatin , dna , swi/snf , oligonucleotide , microbiology and biotechnology , biophysics , biochemistry , chromosomal translocation , gene
The ISWI proteins form the catalytic core of a subset of ATP-dependent chromatin-remodeling activities. Here, we studied the interaction of the ISWI protein with nucleosomal substrates. We found that the ability of nucleic acids to bind and stimulate the ATPase activity of ISWI depends on length. We also found that ISWI is able to displace triplex-forming oligonucleotides efficiently when they are introduced at sites close to a nucleosome but successively less efficiently 30 to 60 bp from its edge. The ability of ISWI to direct triplex displacement was specifically impeded by the introduction of 5- or 10-bp gaps in the 3'-5' strand between the triplex and the nucleosome. In combination, these observations suggest that ISWI is a 3'-5'-strand-specific, ATP-dependent DNA translocase that may be capable of forcing DNA over the surface of nucleosomes.