Viral Transcription During Autographa californica Nuclear Polyhedrosis Virus Infection: a Novel RNA Polymerase Induced in Infected Spodoptera frugiperda Cells

Abstract

Autographa californica nuclear polyhedrosis virus-specific RNA synthesis in isolated nuclei of Spodoptera frugiperda cells in culture was monitored at different times postinfection. Up to 8 h postinfection viral RNA synthesis remained sensitive to 5 ,ug of a-amanitin per ml. During the course of infection this sensitivity decreased, and at 24 h postinfection RNA synthesis was completely resistant to a-amanitin. DEAE-Sephadex profiles of RNA polymerase isolated at 24 h postinfection showed a new, chromatographically distinct, a-amanitinresistant form whose kinetics and response to divalent cations differed from those of the host RNA polymerases. The possibility that this enzyme may be responsible for viral late transcription is discussed.

Baculoviruses: diversity, evolution and manipulation of insects

“…Although both immediate early and delayed early genes have promoters recognized and transcribed by cellular RNA polymerase II, immediate early genes can be expressed efficiently without viral factors, whereas the optimal expression of delayed early genes requires the products of immediate early genes. Late and very late genes are transcribed by a virally encoded RNA polymerase resistant to α-amanitin (Fuchs et al 1983;Yang et al 1991) and consisting of four viral gene products: LEF-4, LEF-8, LEF-9 and P47 (Guarino et al 1998).…”

Expression of PE38 and IE2, viral members of the C3HC4 finger family, during baculovirus infection: PE38 and IE2 localize to distinct nuclear regions

“…The temporal gene expression of AcNPV is sequentially ordered in a cascade, and, to date, the molecular mechanism by which regulation is accomplished is poorly understood (for reviews, see references 3 and 29). One prominent feature of viral gene expression is the induction of an ␣-amanitin-resistant RNA polymerase activity which mediates transcription of the majority of late and very late genes (11,44), while early viral promoters are recognized by the host RNA polymerase II.…”

Competition between baculovirus polyhedrin and p10 gene expression during infection of insect cells

“…Previous functional investigations of the polyhedrin gene promoter (25,26,29,30) and investigations of the plO gene promoter in transient expression systems (32,49,50) allowed the definition of sequences required for their maximum activity. Moreover, like most other late genes, the polyhedrin and plO genes are transcribed by an a-amanitinresistant RNA polymerase induced upon infection (8,13,18). The polyhedrin and plO gene promoters share a 12nucleotide consensus sequence (37) containing an ATAAG motif which is found at the transcription initiation sites of most characterized baculovirus late genes.…”