Vaccinia virus directs the synthesis of early mRNAs containing 5' poly(A) sequences.

Journal Article

mRNAs transcribed from late promoters of several poxvirus genes contain 5' poly(A) sequences that are not complementary to the viral DNA. In contrast, early mRNAs containing 5' poly(A) sequences have not previously been identified. Modifications to the sequence of the promoter of an early gene of cowpox virus enable this promoter to direct the synthesis of RNAs containing 5' poly(A) sequences. When the sequence 3'-ATTTA-5', which is present at the RNA start-sites of several late promoters, is positioned such that the RNA start-site of the early promoter is at the first thymidylate in this sequence, this early promoter directs the synthesis of early RNAs containing 4-11 adenylates at their 5' ends. When two of the thymidylates in the sequence 3'-ATTTA-5' are removed, the promoter directs the synthesis of early RNAs lacking 5' poly(A) sequences. These results are consistent with the proposal that 5' polyadenylylation of poxvirus RNAs occurs by repetitive transcription of thymidylates in the sequence 3'-ATTTA-5' often present at the sites of transcriptional initiation. In addition, these results demonstrate that 5' polyadenylylation of viral RNAs is not exclusively a late function. The promoter regions of a few early genes of vaccinia virus contain the sequence 3'-ATTTA-5'. Analyses of the transcripts of one of these genes, the D5 gene, indicated that these mRNAs contain 5' poly(A) sequences, suggesting that early mRNAs of a subset of viral genes contain 5' poly(A) sequences.

Full Text

Duke Authors

Cited Authors

  • Ink, BS; Pickup, DJ

Published Date

  • February 1990

Published In

Volume / Issue

  • 87 / 4

Start / End Page

  • 1536 - 1540

PubMed ID

  • 1968253

International Standard Serial Number (ISSN)

  • 0027-8424

Language

  • eng

Conference Location

  • United States