An unusual cellular factor potentiates protein-DNA complex assembly between Oct-1 and Vmw65.
The herpes simplex virus trans-activator Vmw65 interacts with the cellular factors Oct-1 and VCAF-1 to generate a multicomponent DNA binding complex that specifically recognizes conserved enhancer elements found upstream of the viral immediate-early genes, resulting in potent stimulation of their transcription. We have identified a HeLa cell factor, distinct from Oct-1 or VCAF-1, which significantly enhances the stability or formation of Vmw65-dependent complexes, as judged by mobility shift analysis using either nuclear extracts or bacterially expressed Oct-1 and Vmw65. This factor, designated SF (stimulatory factor), was partially purified from HeLa cell postnuclear extracts and has an apparent molecular weight of 1500-3000, based on ultrafiltration and size-exclusion chromatography. SF was shown to be resistant to inactivation by heat treatment, protease, nuclease, and phospholipase digestions, and extraction with organic solvents. Pretreatment of SF with beta-glucuronidase did not affect its ability to stimulate Vmw65-dependent complex formation but did reduce the electrophoretic mobility of the resulting complex. These data indicate that SF is probably a component of the Vmw65-induced complex and may be composed, at least partially, of carbohydrate.
Werstuck
G H
GH
Department of Biochemistry, McMaster University, Hamilton, Ontario, Canada.
Capone
J P
JP
D000255:Adenosine Triphosphate / Q000378:metabolism; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D002850:Chromatography, Gel; D003600:Cytosol / Q000378:metabolism; D015342:DNA Probes; D004268:DNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006367:HeLa Cells / Q000378:metabolism; D017405:Herpes Simplex Virus Protein Vmw65 / Q000378:metabolism*; D051863:Host Cell Factor C1; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D050811:Octamer Transcription Factor-1; D009838:Oligodeoxyribonucleotides; D018139:Simplexvirus / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D014462:Ultrafiltration
D015342:DNA Probes; D004268:DNA-Binding Proteins; C497692:HCFC1 protein, human; D017405:Herpes Simplex Virus Protein Vmw65; D051863:Host Cell Factor C1; D050811:Octamer Transcription Factor-1; D009838:Oligodeoxyribonucleotides; C494165:POU2F1 protein, human; D015534:Trans-Activators; D014157:Transcription Factors; D000255:Adenosine Triphosphate