Abstract
A factor designated VLTF-X is required to support vaccinia virus late transcription in vitro. It has been found that a late promoter DNA binding activity cochromatographs and cosediments with VLTF-X activity. Current experiments show that VLTF-X activity is present in a variety of uninfected mammalian cell types and is indistinguishable from that recovered from infected cells based upon several criteria. VLTF-X activity from both sources displays the same purification profile over phosphocellulose and DNA affinity resins and has the same sedimentation coefficient. In addition, the factors purified from both infected and uninfected cells form protein-DNA complexes of identical electrophoretic mobility in the presence of vaccinia virus late promoter-containing DNA. The affinity of these factors for the late promoter probes is identical and late promoter-specific based on competition experiments. Moreover, VLTF-X purified from both sources bound to late promoter-containing DNA in the presence or absence of MgCl2 and ATP and formed complexes resistant to heat inactivation. These experiments offer proof that vaccinia virus factor VLTF-X is a host cell protein that supports transcription of the viral late genes.
Highlights
Poxviruses are large DNA viruses that replicate within the cytoplasm of host cells and encode most of the specific enzymes and factors required for their transcription and replication
We have previously described a factor present in crude, uninfected cell cytoplasmic extracts that could complement for the vaccinia virus late transcription factor designated VLTF-X
It was found that a late promoter DNA binding activity cochromatographed and cosedimented with VLTF-X activity
Summary
Vol 273, No 42, Issue of October 16, pp. 27524 –27530, 1998 Printed in U.S.A. A Vaccinia Virus Late Transcription Factor with Biochemical and Molecular Identity to a Human Cellular Protein*. The factors purified from both infected and uninfected cells form protein-DNA complexes of identical electrophoretic mobility in the presence of vaccinia virus late promotercontaining DNA. VLTF-X purified from both sources bound to late promoter-containing DNA in the presence or absence of MgCl2 and ATP and formed complexes resistant to heat inactivation These experiments offer proof that vaccinia virus factor VLTF-X is a host cell protein that supports transcription of the viral late genes. Recent data have demonstrated that VLTF-X activity is found in uninfected HeLa cell cytoplasmic extracts and virion extracts, defining it as a unique late transcription factor [14] The presence of this factor in uninfected cells was surprising in that it potentially defined another host factor, besides that required for intermediate transcription, that participates in the viral transcriptional machinery. We conclude that VLTF-X purified from both preparations is most likely the same factor
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
