title: Increased Serine-Arginine (SR) Protein Phosphorylation Changes Pre-mRNA Splicing in Hypoxia.
abstract: The removal of introns from mRNA precursors (pre-mRNAs) is an essential step in eukaryotic gene expression. The splicing machinery heavily contributes to biological complexity and especially to the ability of cells to adapt to altered cellular conditions. Inhibitory PAS domain protein (IPAS), a dominant negative regulator of hypoxia-inducible gene expression, is generated from hypoxia inducible transcription factor-3α (HIF-3α) pre-mRNA by an alternative splicing mechanism. Inactivation of the IPAS transcript in mice leads to the neo-vascularization of the cornea, suggesting that IPAS is an important regulator of anti-angiogenesis in this tissue. For the first time we demonstrate that serine-arginine (SR) proteins are involved in oxygen tension-dependent changes in pre-mRNA splicing. SR proteins isolated from hypoxic cells differentially interact with RNA (compared with proteins isolated from cells cultured under normoxic conditions). They possess the differential ability to activate hypoxia-dependent splice sites, and they are more phosphorylated than those isolated from normoxic HeLa cells. We also show that expression of SR protein kinases (CLK1, SRPK1, SRPK2) in hypoxic cells is elevated at mRNA and protein levels. Increased expression of CLK1 kinase is regulated by HIFs. Reduction of CLK1 cellular expression levels reduces hypoxia-dependent full-length carbonic anhydrase IX (CAIX) mRNA and CAIX protein formation and changes hypoxia-dependent cysteine-rich angiogenic inducer 61 (Cyr61) mRNA isoform formation profiles.
authors.affiliation: Department of Immunology and Cell Biology, Vilnius University, Institute of Biotechnology, 02241 Vilnius, Lithuania.
authors.forename: Egle
authors.initials: E
authors.lastname: Jakubauskiene
authors.affiliation: Department of Immunology and Cell Biology, Vilnius University, Institute of Biotechnology, 02241 Vilnius, Lithuania.
authors.forename: Laurynas
authors.initials: L
authors.lastname: Vilys
authors.affiliation: Division of Metabolism and Biosystemic Science, Department of Medicine, Asahikawa Medical College, 078-8510 Asahikawa, Hokkaido, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Makino
authors.affiliation: Department of Cell and Molecular Biology, Medical Nobel Institute, Karolinska Institute, SE-17177 Stockholm, Sweden; Cancer Science Institute, National University of Singapore, 117599 Singapore.
authors.forename: Lorenz
authors.initials: L
authors.lastname: Poellinger
authors.affiliation: Department of Immunology and Cell Biology, Vilnius University, Institute of Biotechnology, 02241 Vilnius, Lithuania. Electronic address: kanopka@ibt.lt.
authors.forename: Arvydas
authors.initials: A
authors.lastname: Kanopka
mesh_terms: D017398:Alternative Splicing; D001120:Arginine / Q000235:genetics / Q000378:metabolism; D015687:Cell Hypoxia; D015971:Gene Expression Regulation, Enzymologic; D006367:HeLa Cells; D006801:Humans; D000860:Hypoxia / Q000235:genetics / Q000378:metabolism*; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics* / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D012322:RNA Precursors / Q000235:genetics* / Q000378:metabolism; D012694:Serine / Q000235:genetics / Q000378:metabolism
chemical_list: D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D012322:RNA Precursors; D012694:Serine; D001120:Arginine; D017346:Protein Serine-Threonine Kinases; D010100:Oxygen
keywords: RNA splicing; alternative splicing; hypoxia; phosphorylation; serine/threonine protein kinase; spliceosome