Overexpression of actin in AcMNPV-infected cells interferes with polyhedrin synthesis and polyhedra formation.
Autographa californica M nuclear polyhedrosis virus (AcMNPV) terminates host protein synthesis during the late stage of infection, at approximately 14 hr postinfection (hpi). If infection takes place in the presence of cytochalasin D (CD), however, host actin synthesis is transiently stimulated and continues to be synthesized until approximately 30 hpi, and the hyperexpression of polyhedrin is delayed from about 20 hpi until about 36 hpi (S. N. Talhouk and L. E. Volkman, Virology 182, 626-634, 1991; N. Wei and L. E. Volkman, Virology 191, 42-48, 1992). To investigate whether these events are causally related, i.e., whether actin synthesis negatively affects polyhedrin synthesis, we constructed recombinant viruses that expressed actin at various levels during infection. We found that the expression of actin by a strong promoter interfered with polyhedrin synthesis at a posttranscriptional level. It also interfered with polyhedra formation, which may suggest a mechanism for the observed paucity of polyhedra in infected midgut columnar epithelial cells in vivo.
Volkman
L
L
Department of Plant and Microbial Biology, University of California, Berkeley 94720, USA. lvolkman@nature.berkeley.edu.
Storm
K
K
Aivazachvili
V
V
Oppenheimer
D
D
D000199:Actins / Q000378:metabolism*; D000818:Animals; D016367:Baculoviridae; D002460:Cell Line; D015967:Gene Expression Regulation, Viral; D000077183:Occlusion Body Matrix Proteins; D014764:Viral Proteins / Q000378:metabolism*; D015678:Viral Structural Proteins
D000199:Actins; D000077183:Occlusion Body Matrix Proteins; D014764:Viral Proteins; D015678:Viral Structural Proteins; C009829:polyhedrin protein, Nucleopolyhedrovirus