Open AccessA chicken hnRNP of the A/B family recognizes the single‐stranded d(CCCTAA) n telomeric repeated motif
Author(s) -
Marsich Eleonora,
Bandiera Antonella,
Tell Gianluca,
Scaloni Andrea,
Manzini Giorgio
Publication year - 2001
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1327.2001.01860.x
Subject(s) - heterogeneous ribonucleoprotein particle , oligonucleotide , ribonucleoprotein , biology , microbiology and biotechnology , gene isoform , nucleotide , electrophoretic mobility shift assay , nuclear protein , genetics , transcription factor , dna , gene , rna
With the aim of identifying proteins able to interact with the C‐rich single‐stranded telomeric repeated motif, three nuclear polypeptides, CBNPα, CBNPβ and CBNPγ, with apparent mobilities in SDS/PAGE of 38, 44 and 55 kDa, respectively, were isolated from mature chicken erythrocytes by affinity chromatography. In situ UV‐cross‐linking experiments demonstrated that CBNPα and CBNPγ interact directly with the telomeric d(CCCTAA) n repeat, whereas CBNPβ does not. Moreover, they provided information on the protein components responsible for each electrophoretic mobility‐shift assay signal. Ion spray and matrix‐assisted laser desorption ionization MS allowed us to identify CBNPα with single‐stranded D‐box‐binding factor (ssDBF), a protein previously characterized as a transcription factor belonging to the A/B family of heterogeneous nuclear ribonucleoproteins, and CBNPβ with an isoform of this protein containing an extra exon. Similarly, CBNPγ was shown to be probably the chicken homolog of hnRNP K, a ribonuclear protein able to bind to polyC oligonucleotides. The relation of CBNPα (i.e. ssDBF), CBNPβ and CBNPγ to a number of similar proteins in the protein and nucleotide sequence databank is discussed. A rather diversified spectrum of functional roles has been assigned to some of these proteins despite the strong sequence homology among them.