A specific isoform of hnRNP D interacts with DNA in the LR1 heterodimer: canonical RNA binding motifs in a sequence-specific duplex DNA binding protein.
The B cell-specific, sequence-specific duplex DNA-binding protein LR1 is a transcriptional activator and may also function in heavy chain class switch recombination. LR1 is composed of two polypeptides, a 106-kDa subunit that is nucleolin, and a 45-kDa subunit that we now show to be a specific isoform of hnRNP D. hnRNP D and nucleolin both contain canonical RNA binding domains (RBDs also called RRMs) and Arg-Gly-Gly (RGG) motifs. Although these motifs are not commonly associated with sequence-specific recognition of duplex DNA, nonetheless LR1 binds duplex DNA with high affinity (KD = 1.8 nM) and clear sequence specificity. Two RBD-RGG proteins can therefore combine to produce a sequence-specific duplex DNA-binding protein.
Dempsey
L A
LA
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8114, USA.
Hanakahi
L A
LA
Maizels
N
N
D000595:Amino Acid Sequence; D001483:Base Sequence; D004247:DNA / Q000378:metabolism*; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000378:metabolism*; D019281:Dimerization; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D008969:Molecular Sequence Data; D011485:Protein Binding; D016601:RNA-Binding Proteins / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000378:metabolism*
D017931:DNA Primers; D004268:DNA-Binding Proteins; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; D004247:DNA