Heterogeneous nuclear RNA-ribonucleoprotein F binds to DNA via an oligo(dG)-motif and is associated with RNA polymerase II.
BACKGROUND
The heterogeneous nuclear ribonucleoprotein F (hnRNP-F) is one of the constituents of the splicing-related hnRNP complex. Recent studies suggest that pre-mRNA modification and splicing factors are associated with transcriptional initiation factors and RNA polymerase II (RNA pol II) at a promoter, implying that pre-mRNA-engaged factors might be associated with a promoter.


RESULTS
We isolated a cDNA of rat hnRNP-F and expressed the recombinant protein. HnRNP-F selectively bound to oligo(dG) in constructions with other oligohomonucleotides. The ssDNA of an SV40 promoter sequence having the GC-boxes was bound to hnRNP-F, while hnRNP-F bound to the (G/C)-stretch as dsDNA. Consequently, hnRNP-F was designated as an oligo(dG)-binding protein. None of the RNA-binding domains (RBDs) in hnRNP-F were critical for the oligo(dG)-binding. In contrast, the GY-rich region that exists between RBD-II and -III exhibited an oligo(dG)-binding ability. We suggest that the GY-rich region is a novel DNA-binding motif. HnRNP-F was shown to contain two types of binding motifs for RNA and DNA. Additionally, we found that hnRNP-F was co-precipitated with RNA pol II. Interestingly, the RNA pol II holoenzyme also contained hnRNP-F. The tissue distribution profile of hnRNP-F was similar to that of both RNA pol II and TBP.


CONCLUSIONS
The above results suggest that hnRNP-F is associated with a transcriptional initiation apparatus that includes RNA pol II. The DNA-binding ability of hnRNP-F might facilitate the entry of pre-mRNA modification/splicing factors at a promoter.
Yoshida
T
T
Department of Biology, Faculty of Science, Chiba University, Japan.
Kokura
K
K
Makino
Y
Y
Ossipow
V
V
Tamura
T
T
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D004247:DNA / Q000737:chemistry* / Q000378:metabolism*; D034541:Heterogeneous-Nuclear Ribonucleoprotein Group F-H; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D008297:Male; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D011401:Promoter Regions, Genetic; D012319:RNA Polymerase II / Q000378:metabolism*; D012332:RNA, Heterogeneous Nuclear / Q000378:metabolism; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012261:Ribonucleoproteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D017384:Sequence Deletion; D013539:Simian virus 40 / Q000235:genetics; D013154:Spleen / Q000378:metabolism; D013737:Testis / Q000378:metabolism; D013950:Thymus Gland / Q000378:metabolism
D034541:Heterogeneous-Nuclear Ribonucleoprotein Group F-H; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D009838:Oligodeoxyribonucleotides; D012332:RNA, Heterogeneous Nuclear; D011994:Recombinant Proteins; D012261:Ribonucleoproteins; C033538:oligodeoxyguanylic acid; D004247:DNA; D012319:RNA Polymerase II