title: The protein Hrb57A of Drosophila melanogaster closely related to hnRNP K from vertebrates is present at sites active in transcription and coprecipitates with four RNA-binding proteins.
abstract: The hnRNP K protein is among the major hnRNA-binding proteins with a strong preference for cytidine-rich sequences. We have cloned a Drosophila hnRNP protein closely related to this vertebrate protein. The protein first identified by the monoclonal antibody Q18 is encoded by a gene located in 57A on polytene chromosomes and has been consequently named Hrb57A. The amino acid sequence of the Hrb57A KH domains and their overall organisation in the protein are remarkably similar to the vertebrate proteins. As the hnRNP K in vertebrates the M(r) 55 000 Drosophila Hrb57A/Q18 protein strongly binds to poly(C) in vitro and is ubiquitously present in nuclei active in transcription. On polytene chromosomes it is found in many puffs and minipuffs. Hrb57A/Q18 specifically coprecipitates four other proteins: Hrb87F/P11 a Drosophila hnRNP A1 homologue, the hnRNA-binding protein S5, the RNA recognition motif-containing protein NonA and the RNA-binding zinc finger-containing protein on ecdysone puffs PEP/X4.
authors.affiliation: Fakultaet fuer Chemie AG,. Molekulare Zellbiochemie, Ruhr-Universitaet, Bochum, Germany.
authors.forename: B T
authors.initials: BT
authors.lastname: Hovemann
authors.forename: I
authors.initials: I
authors.lastname: Reim
authors.forename: S
authors.initials: S
authors.lastname: Werner
authors.forename: S
authors.initials: S
authors.lastname: Katz
authors.forename: H
authors.initials: H
authors.lastname: Saumweber
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000378:metabolism; D002467:Cell Nucleus / Q000737:chemistry; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics* / Q000254:growth & development; D019084:Fluorescent Antibody Technique, Indirect; D015870:Gene Expression; D018507:Gene Expression Regulation, Developmental; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D034641:Heterogeneous-Nuclear Ribonucleoprotein K; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D006801:Humans; D019476:Insect Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D011066:Poly C / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D016601:RNA-Binding Proteins / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000235:genetics*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic; D014714:Vertebrates
chemical_list: D000911:Antibodies, Monoclonal; D018076:DNA, Complementary; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D034641:Heterogeneous-Nuclear Ribonucleoprotein K; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D019476:Insect Proteins; D009687:Nuclear Proteins; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; D011066:Poly C