Transcription of a human neurotropic virus promoter in glial cells: effect of YB-1 on expression of the JC virus late gene.
We have isolated a partial recombinant cDNA clone from a HeLa expression library which encodes a protein capable of binding to the central region of the human neurotropic JC virus (JCV) enhancer/promoter, termed the B region. Sequence analysis revealed a complete homology of the partial cDNA clone to the N-terminal region, of a previously described DNA-binding protein, termed YB-1. Band shift analyses have indicated that the bacterially produced YB-1 interacts specifically with the double-stranded B oligonucleotide as well as the corresponding single-stranded DNA fragment representing the early promoter sequence. Further analysis indicated that the YB-1 protein binds specifically to the C/T-rich sequence of the B domain, which is located in close proximity to the TATA box within the virus enhancer/promoter. Results from cotransfection experiments demonstrated that the full-length (YB-1) but not the partial cDNA enhances expression of the JCV late (JCVL) promoter in glial cells. Cointroduction into glial cells of a recombinant expressing the YB-1 and JCVL deletion mutants indicated that removal of the C/T-rich sequence of the B domain reduces the level of activation of the virus promoter by YB-1. Further cotransfection experiments revealed that the virus transactivating protein T antigen appears to diminish the ability of YB-1 to activate JCVL gene expression. RNA studies indicated that YB-1 is expressed in several cell types and tissues. Examination of YB-1 RNA from mouse brain at various stages of development revealed high levels of YB-1 RNA at early stages of development and lower levels at all subsequent developmental stages.
Kerr
D
D
Jefferson Institute of Molecular Medicine, Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
Chang
C F
CF
Chen
N
N
Gallia
G
G
Raj
G
G
Schwartz
B
B
Khalili
K
K
D000957:Antigens, Viral, Tumor / Q000502:physiology; D001483:Base Sequence; D022762:CCAAT-Enhancer-Binding Proteins; D018076:DNA, Complementary / Q000302:isolation & purification; D004268:DNA-Binding Proteins / Q000502:physiology*; D015870:Gene Expression; D005814:Genes, Viral; D006367:HeLa Cells; D006801:Humans; D007577:JC Virus / Q000235:genetics*; D008969:Molecular Sequence Data; D051839:NFI Transcription Factors; D009457:Neuroglia / Q000821:virology*; D009687:Nuclear Proteins; D009698:Nucleoproteins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic; D051840:Y-Box-Binding Protein 1
D000957:Antigens, Viral, Tumor; D022762:CCAAT-Enhancer-Binding Proteins; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D009698:Nucleoproteins; D014157:Transcription Factors; D051840:Y-Box-Binding Protein 1; C070856:YBX1 protein, human