The role of vaccinia termination factor and cis-acting elements in vaccinia virus early gene transcription termination.
Vaccinia virus early gene transcription termination requires the virion form of the viral RNA polymerase (vRNAP), Nucleoside Triphosphate Phosphohydrolase I (NPHI), ATP, the vaccinia termination factor (VTF), and a U5NU termination signal in the nascent transcript. VTF, also the viral mRNA capping enzyme, binds U5NU, and NPHI hydrolyzes ATP to release the transcript. NPHI can release transcripts independent of VTF and U5NU if vRNAP is not actively elongating. However, VTF and U5NU are required for transcript release from an elongating vRNAP, suggesting that the function of VTF and U5NU may be to stall the polymerase. Here we demonstrate that VTF inhibits transcription elongation by enhancing vRNAP pausing. Hence VTF provides the connection between the termination signal in the RNA transcript and viral RNA polymerase to initiate transcription termination. We also provide evidence that a second cis-acting element downstream of U5NU influences the location and efficiency of early gene transcription termination.
Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260, USA.
Jessica
J
Tate
Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260, USA. Electronic address: gollinck@buffalo.edu.
Paul
P
Gollnick
D000255:Adenosine Triphosphate / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism; D015967:Gene Expression Regulation, Viral; D043583:Nucleoside-Triphosphatase / Q000235:genetics / Q000378:metabolism; D010957:Plasmids / Q000737:chemistry / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D013728:Terminator Regions, Genetic; D014158:Transcription, Genetic; D014616:Vaccinia virus / Q000235:genetics* / Q000378:metabolism; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism; D014771:Virion / Q000235:genetics / Q000378:metabolism
D012333:RNA, Messenger; D014764:Viral Proteins; D000255:Adenosine Triphosphate; D012321:DNA-Directed RNA Polymerases; D043583:Nucleoside-Triphosphatase
Capping enzyme; RNA polymerase; RNA structure; Transcription factors; Transcription termination; Viral transcription