Regulation of infected-cell-specific protein synthesis in SF IPLB-21 cells productively infected with Spodoptera frugiperda multicapsid nuclear polyhedrosis virus.
In Spodoptera frugiperda (SF IPLB-21) cells productively infected with S. frugiperda multicapsid nuclear polyhedrosis virus (SfMNPV), we observed the synthesis of infected-cell-specific polypeptides (ICSPs) using the protein synthesis inhibitor cycloheximide (CX) and the DAN synthesis inhibitor cytosine arabinoside (Ara-C) in an attempt to assess whether a temporal cascade and viral DNA synthesis are involved in the gene expression program of SfMNPV. Inhibition of protein synthesis with CX at 0 h postinfection resulted in the active synthesis of a group of ICSPs immediately after removal of CX, suggesting that these polypeptides, designated alpha-ICSP, did not require de novo protein synthesis for their production. A second group of ICSPs (designated beta-ICSPs), requiring a prior interval of protein synthesis, was detected when CX was added at later times. A third group of ICSPs also needed an interval of ICSP synthesis, but differed from beta-ICSPs in that they required a longer interval of protein synthesis. Moreover, the synthesis of most of these ICSPs also required DNA synthesis, which was demonstrated by addition of Ara-C before and after viral DNA replication; these ICSPs were therefore designated gamma-ICSPs. In conclusion, two kinds of regulatory processes are involved in SfMNPV infection: the first process controls the sequential synthesis of the tree ICSP groups, that is alpha-->beta-->gamma; a second process represses the synthesis of ICSP groups, first of the alpha-ICSPs and subsequently of beta-ICSPs. Thus, we propose temporally regulated as well as negative control circuits in SfMNPV gene expression.
Liu
H S
HS
Department of Biological Sciences, Texas Tech University, Lubbock, USA. a713@mail.ncku.edu.tw
Bilimoria
S L
SL
D000818:Animals; D002460:Cell Line; D003513:Cycloheximide / Q000494:pharmacology; D003561:Cytarabine / Q000494:pharmacology; D004279:DNA, Viral / Q000096:biosynthesis; D015967:Gene Expression Regulation, Viral / Q000502:physiology; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D017924:Nucleopolyhedroviruses / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D018411:Spodoptera / Q000821:virology*; D014764:Viral Proteins / Q000096:biosynthesis*; D014779:Virus Replication / Q000502:physiology
D004279:DNA, Viral; D019384:Nucleic Acid Synthesis Inhibitors; D011500:Protein Synthesis Inhibitors; D014764:Viral Proteins; D003561:Cytarabine; D003513:Cycloheximide