Mutational analysis of the core, spacer, and initiator regions of vaccinia virus intermediate-class promoters - PubMed (original) (raw)

Mutational analysis of the core, spacer, and initiator regions of vaccinia virus intermediate-class promoters

C J Baldick Jr et al. J Virol. 1992 Aug.

Abstract

Activation of vaccinia virus late gene transcription is dependent on DNA replication and the expression of three genes: A1L, A2L, and G8R (J. G. Keck, C. J. Baldick, Jr., and B. Moss, Cell 61:801-809, 1990). To fully characterize the promoter elements of these trans-activator genes, we prepared more than 140 plasmid vectors containing natural and mutated DNA segments ligated to the Escherichia coli lacZ or chloramphenicol acetyltransferase reporter gene. Expression of the reporter genes occurred when the plasmids were transfected into vaccinia virus-infected cells and was enhanced when DNA replication was prevented, indicating that the A1L, A2L, and G8R promoters belong to the intermediate regulatory class. Deletional mutagenesis demonstrated that the regulatory elements of all three promoters extended between 20 and 30 nucleotides upstream of their RNA start sites. Single-base substitutions of the G8R promoter revealed two critical elements located from -26 to -13 (the core element) and -1 to +3 (the initiator element). Mutations in these regions drastically affected expression, as determined by beta-galactosidase and mRNA analyses. Additional mutations defined the TAAA sequence as the critical initiator element. The length, but not the nucleotide sequence, of the segment between the core and initiator regions was crucial. The requirement for the spacer to be 10 or 11 nucleotides was consistent with a single turn of a double helix. The A1L and A2L promoters resembled the G8R promoter, and mutations in the conserved bases had the predicted effects on expression. We concluded that the three intermediate promoters are composed of a 14-bp A+T-rich core sequence separated by one turn of the double helix from the TAAA initiator element.

PubMed Disclaimer

Similar articles

Cited by

References

    1. Proc Natl Acad Sci U S A. 1989 Aug;86(16):6126-30 - PubMed
    1. J Virol. 1989 Oct;63(10):4224-33 - PubMed
    1. Virology. 1987 May;158(1):206-10 - PubMed
    1. Anal Biochem. 1987 Apr;162(1):156-9 - PubMed
    1. EMBO J. 1986 Aug;5(8):1951-7 - PubMed

MeSH terms

Substances

LinkOut - more resources