摘要
Baculoviruses encode a DNA-directed RNA polymerase that is evolutionarily divergent from cellular polymerases. This RNA polymerase is a multifunctional complex that has the ability to recognize late promoters, transcribe linked genes, and process transcripts at both the 5’ and 3’ ends. The LEF-4 subunit of the viral RNA polymerase is the mRNA capping enzyme, with both RNA triphosphatase and guanylyltransferase activities. Conversion to cap 1 structures is mediated by the viral enzyme MTase1 and another as yet unidentified methyltransferase. Termination is an intrinsic property of the viral RNA polymerase and occurs at oligoU rich sequences. Polyadenylation of the released transcripts is also a function of the viral RNA polymerase. Thus, although viral mRNAs resemble host messages with respect to their 5’ and 3’ end structures, the processing is mediated by viral enzymes and, in the case of the 3’ ends, by mechanisms that differ from the host cell.
Baculoviruses encode a DNA-directed RNA polymerase that is evolutionarily divergent from cellular polymerases. This RNA polymerase is a multifunctional complex that has the ability to recognize late promoters, transcribe linked genes, and process transcripts at both the 5＇ and 3＇ ends. The LEF-4 subunit of the viral RNA polymerase is the mRNA capping enzyme, with both RNA triphosphatase and guanylyltransferase activities. Conversion to cap 1 structures is mediated by the viral enzyme MTasel and another as yet unidentified methyltransferase, Fermination is an intrinsic property of the viral RNA polymerase and occurs at oligoU rich sequences. Polyadenylation of the released transcripts is also a function of the viral RNA polymerase. Thus, although viral mRNAs resemble host messages with respect to their 5＇ and 3＇ end structures, the processing is mediated by viral enzymes and, in the case of the 3＇ ends, by mechanisms that differ from the host cell.
出处
《中国病毒学》
CSCD
2007年第2期108-116,共9页
Virologica Sinica
基金
Grant MCB-0416484 from the National Science Foundation
关键词
杆状病毒
聚合酶
RNA
基因编码
Baculoviruses
DNA-directed RNA polymerase
Evolutionarily divergent
