title: Single molecule imaging of Tid1/Rdh54, a Rad54 homolog that translocates on duplex DNA and can disrupt joint molecules.
abstract: The Saccharomyces cerevisiae Tid1 protein is important for the recombinational repair of double-stranded DNA breaks during meiosis. Tid1 is a member of Swi2/Snf2 family of chromatin remodeling proteins and shares homology with Rad54. Members of this family hydrolyze ATP and promote 1) chromatin remodeling, 2) DNA topology alterations, and 3) displacement of proteins from DNA. All of these activities are presumed to require translocation of the protein on DNA. Here we use single-molecule visualization to provide direct evidence for the ability of Tid1 to translocate on DNA. Tid1 translocation is ATP-dependent, and the velocities are broadly distributed, with the average being 84 +/- 39 base pairs/s. Translocation is processive, with the average molecule traveling approximately 10,000 base pairs before pausing or dissociating. Many molecules display simple monotonic unidirectional translocation, but the majority display complex translocation behavior comprising intermittent pauses, direction reversals, and velocity changes. Finally, we demonstrate that translocation by Tid1 on DNA can result in disruption of three-stranded DNA structures. The ability of Tid1 translocation to clear DNA of proteins and to migrate recombination intermediates may be of critical importance for DNA repair and chromosome dynamics.
authors: Section of Microbiology, University of California, Davis, California 95616, USA.
authors: Amitabh V
authors: AV
authors: Nimonkar
authors: Ichiro
authors: I
authors: Amitani
authors: Ronald J
authors: RJ
authors: Baskin
authors: Stephen C
authors: SC
authors: Kowalczykowski
mesh_terms: D000251:Adenosine Triphosphatases; D000255:Adenosine Triphosphate / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D042002:Chromatin Assembly and Disassembly / Q000502:physiology; D015825:Chromosomes, Fungal / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004247:DNA / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded; D004265:DNA Helicases; D004260:DNA Repair / Q000502:physiology*; D045643:DNA Repair Enzymes; D026942:DNA Topoisomerases; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006868:Hydrolysis; D011485:Protein Binding / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D000255:Adenosine Triphosphate; D004247:DNA; D000251:Adenosine Triphosphatases; C075468:RAD54 protein, S cerevisiae; C499333:SNF2 protein, S cerevisiae; D004265:DNA Helicases; D026942:DNA Topoisomerases; C541336:RDH54 protein, S cerevisiae; D045643:DNA Repair Enzymes