Molecular cloning and characterization of PEBP2 beta, the heterodimeric partner of a novel Drosophila runt-related DNA binding protein PEBP2 alpha.
Polyomavirus enhancer binding protein, PEBP2 (PEA2), is a heterodimer of two distinct subunits, alpha and beta, of which the former directly binds to DNA and the latter acts auxiliary to enhance the DNA binding. Recent cloning studies has revealed that the alpha subunit is homologous to the products of the Drosophila segmentation gene runt and the human AML1 gene, and that it functions as a major regulator for the T cell-specific gene expression. We have currently cloned cDNAs for the beta subunit. The isolated cDNAs contain three isoforms that are presumed to arise from alternative RNA splicing and encode polypeptides consisting of 187, 182, and 155 amino acids, respectively. These polypeptides neither show any significant homology with known other proteins including the alpha subunit nor have any known DNA-binding and dimerization domains. Thus, PEBP2, as the complex of these subunits, is thought to constitute an entirely novel category of heteromeric transcriptional regulator together with the Runt and AML1 proteins. Gel retardation assays of the cDNA-encoded proteins produced in an in vitro translation system or in Escherichia coli demonstrated that the larger two beta isoforms, but not the smallest one, can dimerize with the alpha subunit. Furthermore, this heterodimerization was shown to cause a marked increase in the intrinsic DNA binding affinity of the alpha subunit.
Department of Viral Oncology, Kyoto University, Japan.
E
E
Ogawa
M
M
Inuzuka
M
M
Maruyama
M
M
Satake
M
M
Naito-Fujimoto
Y
Y
Ito
K
K
Shigesada
D016475:3T3 Cells; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D050659:Core Binding Factor Alpha 1 Subunit; D050676:Core Binding Factor Alpha 2 Subunit; D050657:Core Binding Factor alpha Subunits; D050658:Core Binding Factor beta Subunit; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics*; D029721:Drosophila Proteins; D004926:Escherichia coli / Q000235:genetics; D046911:Macromolecular Substances; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000235:genetics; D009374:Neoplasms, Experimental; D009687:Nuclear Proteins / Q000302:isolation & purification; D011120:Polyomavirus / Q000235:genetics*; D011487:Protein Conformation; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger / Q000235:genetics; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D050656:Transcription Factor AP-2; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics*
D050659:Core Binding Factor Alpha 1 Subunit; D050676:Core Binding Factor Alpha 2 Subunit; D050657:Core Binding Factor alpha Subunits; D050658:Core Binding Factor beta Subunit; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D046911:Macromolecular Substances; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; C493726:Runx1 protein, mouse; C493716:Runx2 protein, mouse; D050656:Transcription Factor AP-2; D014157:Transcription Factors; C080833:run protein, Drosophila; C065788:transcription factor PEA3