title: The nuclear localization of SWI/SNF proteins is subjected to oxygen regulation.
abstract: BACKGROUND
  Hypoxia is associated with many disease conditions in humans, such as cancer, stroke and traumatic injuries. Hypoxia elicits broad molecular and cellular changes in diverse eukaryotes. Our recent studies suggest that one likely mechanism mediating such broad changes is through changes in the cellular localization of important regulatory proteins. Particularly, we have found that over 120 nuclear proteins with important functions ranging from transcriptional regulation to RNA processing exhibit altered cellular locations under hypoxia. In this report, we describe further experiments to identify and evaluate the role of nuclear protein relocalization in mediating hypoxia responses in yeast.
  
  
  RESULTS
  To identify regulatory proteins that play a causal role in mediating hypoxia responses, we characterized the time courses of relocalization of hypoxia-altered nuclear proteins in response to hypoxia and reoxygenation. We found that 17 nuclear proteins relocalized in a significantly shorter time period in response to both hypoxia and reoxygenation. Particularly, several components of the SWI/SNF complex were fast responders, and analysis of gene expression data show that many targets of the SWI/SNF proteins are oxygen regulated. Furthermore, confocal fluorescent live cell imaging showed that over 95% of hypoxia-altered SWI/SNF proteins accumulated in the cytosol in hypoxic cells, while over 95% of the proteins were nuclear in normoxic cells, as expected.
  
  
  CONCLUSIONS
  SWI/SNF proteins relocalize in response to hypoxia and reoxygenation in a quick manner, and their relocalization likely accounts for, in part or in whole, oxygen regulation of many SWI/SNF target genes.
authors.affiliation: Department of Molecular and Cell Biology, Center for Systems Biology, University of Texas at Dallas, Mail Stop RL11 800 W Campbell Road, Richardson, TX, 75080, USA.
authors.forename: Ranita Ghosh
authors.initials: RG
authors.lastname: Dastidar
authors.affiliation: Department of Molecular and Cell Biology, Center for Systems Biology, University of Texas at Dallas, Mail Stop RL11 800 W Campbell Road, Richardson, TX, 75080, USA.
authors.forename: Jagmohan
authors.initials: J
authors.lastname: Hooda
authors.affiliation: Department of Molecular and Cell Biology, Center for Systems Biology, University of Texas at Dallas, Mail Stop RL11 800 W Campbell Road, Richardson, TX, 75080, USA.
authors.forename: Ajit
authors.initials: A
authors.lastname: Shah
authors.affiliation: Department of Molecular and Cell Biology, Center for Systems Biology, University of Texas at Dallas, Mail Stop RL11 800 W Campbell Road, Richardson, TX, 75080, USA.
authors.forename: Thai M
authors.initials: TM
authors.lastname: Cao
authors.affiliation: Department of Molecular and Cell Biology, Center for Systems Biology, University of Texas at Dallas, Mail Stop RL11 800 W Campbell Road, Richardson, TX, 75080, USA.
authors.forename: Robert Michael
authors.initials: RM
authors.lastname: Henke
authors.affiliation: Department of Molecular and Cell Biology, Center for Systems Biology, University of Texas at Dallas, Mail Stop RL11 800 W Campbell Road, Richardson, TX, 75080, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang