Dataset Information

Hypoxia-induced subnuclear re-distribution of SAFB1/2 alters their respective interactome

ABSTRACT: Oxygen deprivation (hypoxia) is encountered in physiological conditions but also characterizes many pathological conditions including ischemia and cancer. In order to survive, the cells usually rely upon the activation of the Hypoxia Inducible Factors (HIF), a small family of heterodimeric transcriptional activators. However, adaption to hypoxia also involves, lesser-known, HIF-independent processes that affect chromatin remodelling and nuclear architecture. SAFB1/2 (Scaffold Attachment Factors B1 and 2) are integral components of the nuclear matrix of vertebrate cells and known to affect functions that include transcriptional regulation, RNA processing and response to DNA damage. Our work indicates that SAFB1/2 swiftly change their localization from the insoluble matrix fraction to more soluble nuclear fractions in a HIF-independent manner. To extend our study, we performed immunoprecipitation experiments with SAFB1 or SAFB2 from cells exposed to both normoxia and short-term hypoxia (2 hours). Mass spectrometry analysis of the immunoprecipitates revealed that short-term exposure of cells to low oxygen levels alters the protein-protein interactions of SAFB1/2 mainly with proteins implicated in mRNA maturation and transcriptional control. Our data suggest that SAFB1/2 proteins participate in molecular mechanisms immediately responsive to hypoxia that entail their rapid mobilization from the nuclear matrix and their altered association with constituents of splicing and transcriptional machinery.

INSTRUMENT(S): LTQ Orbitrap XL

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Epithelial Cell, Cell Culture

DISEASE(S): Breast Cancer

SUBMITTER: Martina Samiotaki

LAB HEAD: Ilias Mylonis

PROVIDER: PXD030933 | Pride | 2023-03-10

REPOSITORIES: Pride

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Publications

Short-term hypoxia triggers ROS and SAFB mediated nuclear matrix and mRNA splicing remodeling.

Taze Chrysa C Drakouli Sotiria S Samiotaki Martina M Panayotou George G Simos George G Georgatsou Eleni E Mylonis Ilias I

Redox biology 20221117

The cellular response to hypoxia, in addition to HIF-dependent transcriptional reprogramming, also involves less characterized transcription-independent processes, such as alternative splicing of the VEGFA transcript leading to the production of the proangiogenic VEGF form. We now show that this event depends on reorganization of the splicing machinery, triggered after short-term hypoxia by ROS production and intranuclear redistribution of the nucleoskeletal proteins SAFB1/2. Exposure to low oxy ...[more]

PMID: 36427398

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Project description:Alternative RNA splicing analysis in Hep3B cell cultured under 21% (N1,3,5) or 1.2% (H2,4,6) oxygen Hypoxia is a common characteristic of many solid tumors. The hypoxic microenvironment stabilizes hypoxia-inducible transcription factor 1? (HIF1?) and 2? (HIF2?) to activate gene transcription, which promotes tumor cell survival. 95% of human genes are alternatively spliced, producing RNA isoforms that code functionally distinct proteins. Thus, effective hypoxia response requires increased HIF target gene transcription as well as proper RNA splicing of these HIF target genes. However, it is unclear if and how hypoxia regulates RNA splicing of HIF target genes. This study determined the effects of hypoxia on alternative splicing (AS) of HIF and non-HIF target genes in Hep3B cells and characterized the role of HIF in regulating AS of HIF induced genes. The results indicated that hypoxia generally promotes exon inclusion for hypoxia-induced, but reduces exon inclusion for hypoxia reduced genes. Mechanistically, HIF activity, but not hypoxia per se is found to be necessary and sufficient to increase exon inclusion of several HIF target genes including pyruvate dehydrogenase kinase 1 (PDK1). PDK1 splicing reporters confirmed that transcriptional activation by HIF is sufficient to increase exon inclusion of PDK1 splicing reporter. In contrast, transcriptional activation of the PDK1 minigene by other transcription factor in the absence of endogenous HIF target gene activation fails to alter PDK1 RNA splicing, demonstrating a novel role of HIF target gene(s) in regulating RNA splicing of HIF target genes. Implications:This study demonstrates a novel function of HIF in regulating RNA splicing of HIF target genes. We analyzed total RNA from Hep3B cells cultured under 21% (N1,3,5) or 1.2% (H2,4,6) oxygen using the Affymetrix Human Exon 1.0 ST platform. Array data was processed by Altanalyze software version 2.0.7. Techinical replicates were performed for Nx and Hx treated Hep3B cells

Dataset Information

Hypoxia-induced subnuclear re-distribution of SAFB1/2 alters their respective interactome

Publications

Short-term hypoxia triggers ROS and SAFB mediated nuclear matrix and mRNA splicing remodeling.

Similar Datasets

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