Adenovirus type 5 DNA-protein complexes from formaldehyde cross-linked cells early after infection. Journal   Virology. Citation   Virology. 312(1):204-12 Publication date   2003 Jul 20 Authors   Spector DJ Johnson JS Baird NL Engel DA Investigators   David J. Spector Grant agencies   National Cancer Institute National Institute of General Medical Sciences Grants   NCI CA60675 NIGMS GM58214 MeSH headings   Adenoviridae DNA, Viral Formaldehyde Viral Proteins MeSH qualifiers   genetics metabolism chemistry Abstract   We report here the properties of viral DNA-protein complexes that purify with cellular chromatin following formaldehyde cross-linking of intact cells early after infection. The cross-linked viral DNA fractionated into shear-sensitive (S) and shear- resistant (R) components that were separable by sedimentation, which allowed independent characterization. The R component had the density and sedimentation properties expected for DNA-protein complexes and contained intact viral DNA. It accounted for about 50% of the viral DNA recovered at 1.5 h after infection but less than 20% by 4.5 h. The proportion of R component was independent of multiplicity of infection, even at less than one particle per cell. Viral hexon and protein VII, but not protein VI, were detected in the fractions containing the R component. These properties are consistent with those of partially uncoated virions associated with the nuclear envelope. A substantial proportion of the S component viral DNA had the same density as cellular chromatin. Protein VII was the most abundant viral protein present in gradient fractions that contained the S component. Complexes containing USF transcription factor cross-linked to the adenovirus major late promoter were detected by viral chromatin immunoprecipitation of the fractions containing S component. The S component probably contained uncoated nuclear viral DNA that assembles into early viral transcription complexes. Medline ID   22773634