Characterization of late gene expression factors lef-9 and lef-8 from Bombyx mori nucleopolyhedrovirus.
Late gene expression factors, LEF-4, LEF-8, LEF-9 and P47 constitute the primary components of the Autographa californica multinucleocapsid polyhedrovirus (AcMNPV)-encoded RNA polymerase, which initiates transcription from late and very late promoters. Here, characterization of lef-9 and lef-8, which encode their corresponding counterparts, from Bombyx mori NPV is reported. Transcription of lef-9 initiated at two independent sites: from a GCACT sequence located at -38 nt and a CTCTT sequence located at -50 nt, with respect to the +1 ATG of the open reading frame. The 3' end of the transcript was mapped to a site 17 nt downstream of a canonical polyadenylation signal located 7 nt downstream of the first of the two tandem translational termination codons. Maximum synthesis of LEF-9 was seen from 36 h post-infection (p.i.). The transcription of lef-8 initiated early in infection from a GTGCAAT sequence that differed in the corresponding region from its AcMNPV counterpart (GCGCAGT), with consequent elimination of the consensus early transcription start site motif (underlined). Peak levels of lef-8 transcripts were attained by 24 h p.i. Immunocopurification analyses suggested that there was an association between LEF-8 and LEF-9 in vivo.
Acharya
Asha
A
Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India1.
Gopinathan
Karumathil P
KP
Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India1.
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D012831:Bombyx / Q000821:virology*; D002460:Cell Line; D003001:Cloning, Molecular; D015967:Gene Expression Regulation, Viral; D008969:Molecular Sequence Data; D017924:Nucleopolyhedroviruses / Q000235:genetics / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D014764:Viral Proteins; C087702:late expression factor 8, Baculovirus