Lamin B1 controls oxidative stress responses via Oct-1.
Interaction of lamins with chromatin and transcription factors regulate transcription. Oct-1 has previously been shown to colocalize partly with B-type lamins and is essential for transcriptional regulation of oxidative stress response genes. Using sequential extraction, co-immunoprecipitation (IP), fluorescence loss in photobleaching, and fluorescence resonance energy transfer, we confirm Oct-1-lamin B1 association at the nuclear periphery and show that this association is lost in Lmnb1(Delta/Delta) cells. We show that several Oct-1-dependent genes, including a subset involved in oxidative stress response, are dysregulated in Lmnb1(Delta/Delta) cells. Electrophoretic mobility shift assay and chromatin IP reveal that Oct-1 binds to the putative octamer-binding sequences of the dysregulated genes and that this activity is increased in cells lacking functional lamin B1. Like Oct1(-/-) cells, Lmnb1(Delta/Delta) cells have elevated levels of reactive oxygen species and are more susceptible to oxidative stress. Sequestration of Oct-1 at the nuclear periphery by lamin B1 may be a mechanism by which the nuclear envelope can regulate gene expression and contribute to the cellular response to stress, development, and aging.
Malhas
Ashraf N
AN
Department of Physics, Sir William Dunn School of Pathology, University of Oxford, Oxford, England, UK.
Lee
Chiu Fan
CF
Vaux
David J
DJ
D000818:Animals; D002478:Cells, Cultured; D016922:Cellular Senescence; D047369:Chromatin Immunoprecipitation; D024202:Electrophoretic Mobility Shift Assay; D005786:Gene Expression Regulation; D034921:Lamin Type B / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D034881:Nuclear Lamina / Q000378:metabolism; D050811:Octamer Transcription Factor-1 / Q000378:metabolism / Q000502:physiology*; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism
D034921:Lamin Type B; D050811:Octamer Transcription Factor-1; D017382:Reactive Oxygen Species