Chicken YB-2, a Y-box protein, is a potent activator of Rous sarcoma virus long terminal repeat-driven transcription in avian fibroblasts.
We have previously reported on the cloning and characterization of chk-YB-2, a novel member of the Y-box family of proteins, that binds to the sequence 5'-GTACCACC-3' present on the noncoding strand of the Rous sarcoma virus (RSV) long terminal repeat (LTR) in a single-strand-specific manner. Here, we demonstrate that deletion or mutation of this motif not only eliminates chk-YB-2 binding in vitro but also down-regulates RSV LTR-driven transcription in avian cells. Selective abrogation of chk-YB-2 expression by using antisense oligonucleotides decreased RSV LTR-driven transcription in a promoter-specific manner. This inhibition was not observed when a reporter construct with a deletion in the chk-YB-2 binding site was used. Depletion of cellular chk-YB-2 by transfecting the cells with excess of its recognition sequence oligonucleotides also resulted in reduced transcription from the RSV LTR. Taken together, these results suggest that chk-YB-2 acts as an activator of LTR-promoted transcription in avian cells and that this activation is mediated primarily through the sequence 5'-GTACCACC-3'.
Swamynathan
S K
SK
Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri-Columbia, 65212, USA.
Nambiar
A
A
Guntaka
R V
RV
D000818:Animals; D030161:Avian Proteins; D001358:Avian Sarcoma Viruses / Q000235:genetics*; D001483:Base Sequence; D001665:Binding Sites; D002642:Chick Embryo; D004268:DNA-Binding Proteins / Q000235:genetics*; D015967:Gene Expression Regulation, Viral; D008969:Molecular Sequence Data; D011743:Pyrimidines / Q000378:metabolism; D012091:Repetitive Sequences, Nucleic Acid; D017384:Sequence Deletion; D015534:Trans-Activators / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic; D015533:Transcriptional Activation
D030161:Avian Proteins; D004268:DNA-Binding Proteins; D011743:Pyrimidines; D015534:Trans-Activators; D014157:Transcription Factors; C101555:YB-2 protein, Gallus gallus; C030986:pyrimidine