Discontinuous transcription or RNA processing of vaccinia virus late messengers results in a 5′ poly(A) leader

It is demonstrated by primer elongation and cap analysis that mature vaccinia virus late transcripts are discontinuously synthesized and Sequencing of the RNA and of the first strand cDNA reveal that a homopolymeric poly(A) sequence is linked to the 5′ terminus of theRNA transcripts.

Abstract

We have demonstrated by primer elongation and cap analysis that mature vaccinia virus late transcripts are discontinuously synthesized. We have shown that RNA transcripts from a translocated 11K and from the authentic 11K and 4b late promoters are extended by approximately 35 nucleotides beyond the "start site" determined by S1 mapping using vaccinia genomic DNA as a probe. Sequencing of the RNA and of the first strand cDNA reveal that a homopolymeric poly(A) sequence is linked to the 5' terminus of the RNA transcripts. S1 mapping of RNA transcripts with a DNA probe containing an A-stretch, replacing promoter sequences upstream of position -1, confirms the existence of a poly(A) leader of approximately 35 A-residues.