Vaccinia virus capping enzyme is a transcription initiation factor - PubMed (original) (raw)
Vaccinia virus capping enzyme is a transcription initiation factor
J C Vos et al. EMBO J. 1991 Sep.
Abstract
It has previously been demonstrated that vaccinia virus capping enzyme is involved both in the formation of a 5' cap structure and in termination of early transcription. Here we show that capping enzyme has an additional activity which is required for transcription of intermediate genes. VITF-A and VITF-B have been defined as two activities which together with RNA polymerase are necessary and sufficient to transcribe intermediate genes in vitro. VITF-A and the viral capping enzyme are shown to copurify to near homogeneity. Direct evidence that capping enzyme is VITF-A was obtained by complementation of a reconstituted transcription system with viral capping enzyme expressed in Escherichia coli. Although capping enzyme is a cofactor in early transcription termination, intermediate transcription is not terminated in response to the early termination signal. Capping enzyme is shown to form a complex with RNA polymerase in the absence of VITF-B. This appears to be a prerequisite for the formation of a stable initiation complex.
References
- Cell. 1991 Apr 5;65(1):105-13 - PubMed
- J Biol Chem. 1975 Dec 25;250(24):9322-9 - PubMed
- J Biol Chem. 1988 Aug 5;263(22):10754-60 - PubMed
- J Biol Chem. 1987 Sep 5;262(25):12372-80 - PubMed
- J Virol. 1988 Jun;62(6):1889-97 - PubMed
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