Samenvatting
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 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.
Originele taal-2 | Engels |
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Pagina's (van-tot) | 2553-2558 |
Aantal pagina's | 6 |
Tijdschrift | EMBO Journal |
Volume | 10 |
Nummer van het tijdschrift | 9 |
DOI's | |
Status | Gepubliceerd - 1991 |
Extern gepubliceerd | Ja |