title: Splice isoform of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-4: expression and hypoxic regulation.
abstract: The 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFKFB) is responsible for maintaining the cellular levels of fructose-2,6-bisphosphate which is a key regulator of glycolysis. Here we have studied the expression of PFKFB-4 isozyme in the DB-1 melanoma cells. An additional isoform of PFKFB-4 mRNA with 148 bases insert in the amino-terminal region at high constitutive levels was identified in these cells. The expression of this splice isoform as well as main isoform of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase was responsible to hypoxia and dimethyloxalylglycine, an inhibitor of HIF-1 alpha hydroxylase enzymes, suggesting that the hypoxia responsiveness of PFKFB-4 gene in these cells is regulated by HIF-1alpha protein. Hypoxic induction of PFKFB4 mRNA in the DB-1 melanoma cells correlates with the expression of PFKFB-3 and VEGF mRNA which are known as HIF-1 dependent genes. Thus, our results clearly demonstrated the existence of splice isoform of PFKFB-4 mRNA in the DB-1 melanoma cells and its overexpression under hypoxic conditions.
authors.affiliation: Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, 9 Leontovycha Street, Kyiv, 01601, Ukraine. ominchenko@yahoo.com
authors.forename: Oleksandr H
authors.initials: OH
authors.lastname: Minchenko
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Ogura
authors.forename: Iryna L
authors.initials: IL
authors.lastname: Opentanova
authors.forename: Dmytro O
authors.initials: DO
authors.lastname: Minchenko
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Esumi
mesh_terms: D000180:Acrylic Resins; D017398:Alternative Splicing / Q000235:genetics*; D001681:Biological Assay; D015153:Blotting, Western; D015687:Cell Hypoxia / Q000235:genetics*; D045744:Cell Line, Tumor; D005635:Fructosediphosphates / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007527:Isoenzymes; D010190:Pancreatic Neoplasms; D025481:Phosphofructokinase-2 / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D012260:Ribonucleases / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics
chemical_list: D000180:Acrylic Resins; D005635:Fructosediphosphates; D007527:Isoenzymes; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; C016680:polyacrylamide gels; C027652:fructose 2,6-diphosphate; D025481:Phosphofructokinase-2; D012260:Ribonucleases