Transcription map and expression of bovine herpesvirus-1 glycoprotein D in early region 4 of bovine adenovirus-3.
Early region 4 (E4) of bovine adenovirus type 3 (BAV-3) was analyzed by Northern blotting, RT-PCR analysis, cDNA sequencing, and S1 nuclease protection assays. The transcriptional map of the E4 region of BAV-3 has marked dissimilarities from those of mouse adenovirus-1, ovine adenovirus-287, and human adenovirus-2, for which the transcriptional maps have been constructed. The E4 region of BAV-3, located between 98.6 and 89.8 MU transcribes seven distinct classes of bovine adenovirus type 3 mRNA. The seven mRNA species formed by the removal of one to three introns share both the 3' end and a short 5' leader (25 nucleotides). The E4 mRNAs can encode at least five unique polypeptides, namely, 143R1, 69R, 143R2, 268R, and 219R. Isolation of a replication-competent recombinant "BAV404" containing 1.9-kb insertion [glycoprotein (gD) of bovine herpesvirus 1, under the control of a SV40 early promoter and poly(A)] in the region between E4 and the right ITR suggested that this region is nonessential for BAV-3 replication. Expression of gD by BAV404 recombinant virus was confirmed by immunoprecipitation with gD-specific monoclonal antibodies. Analysis of the kinetics of protein expression indicated that gD is expressed at both early and late times postinfection. These results suggest that: (a) E4 produces seven 5'-3' coterminal mRNAs and (b) the right terminal region of BAV-3 can be used for the expression of vaccine antigens.
Baxi
M K
MK
Veterinary Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5E3, Canada.
Babiuk
L A
LA
Mehtali
M
M
Tikoo
S K
SK
D017504:Adenovirus E4 Proteins / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D015152:Blotting, Northern; D002417:Cattle; D018076:DNA, Complementary; D017921:Mastadenovirus / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D010957:Plasmids; D011233:Precipitin Tests; D011994:Recombinant Proteins / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015719:Single-Strand Specific DNA and RNA Endonucleases / Q000378:metabolism; D014158:Transcription, Genetic; D014162:Transfection; D014764:Viral Proteins / Q000096:biosynthesis / Q000235:genetics*
D017504:Adenovirus E4 Proteins; D018076:DNA, Complementary; D011994:Recombinant Proteins; D014764:Viral Proteins; C046998:bovine herpesvirus type-1 glycoproteins; D015719:Single-Strand Specific DNA and RNA Endonucleases