Flock house virus: down-regulation of subgenomic RNA3 synthesis does not involve coat protein and is targeted to synthesis of its positive strand.
Flock house virus is a small insect virus with a bipartite RNA genome consisting of RNA1 and RNA2. RNA3 is a subgenomic element encoded by RNA1, the genomic segment required for viral RNA synthesis (T. M. Gallagher, P. D. Friesen, and R. R. Rueckert, J. Virol. 46:481-489, 1983). Synthesis of RNA3 is strongly inhibited by RNA2, the gene for viral coat protein. Evidence that coat protein is not the regulatory element was obtained by using a defective interfering RNA2 which was messenger inactive. It was also found that RNA2 selectively down-regulated synthesis of positive-strand RNA3 but not of its complementary negative strand. cDNA-generated RNA2 transcripts, carrying four extra nonviral bases at the 3' end, failed to repress synthesis of RNA3 but recovered this activity after a single passage in Drosophila cells in the presence of RNA1, suggesting that down-regulation of RNA3 synthesis is controlled by competition with RNA2 for viral replicase.
Zhong
W
W
Institute for Molecular Virology, University of Wisconsin-Madison 53706-1596.
Rueckert
R R
RR
D000818:Animals; D001483:Base Sequence; D002213:Capsid / Q000378:metabolism; D002478:Cells, Cultured; D015536:Down-Regulation; D004330:Drosophila; D016679:Genome, Viral; D007304:Insect Viruses / Q000235:genetics* / Q000378:metabolism; D008957:Models, Genetic; D008969:Molecular Sequence Data; D012328:RNA Viruses / Q000235:genetics* / Q000378:metabolism; D012330:RNA, Double-Stranded / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D012367:RNA, Viral / Q000096:biosynthesis*
D012330:RNA, Double-Stranded; D012333:RNA, Messenger; D012367:RNA, Viral