Characterization of a late gene, ORF134, from Bombyx mori nucleopolyhedrovirus.
OBJECTIVE
ORF134 of Bombyx mori nucleopolyhedrovirus (BmNPV) is a homolog of Autographa californica multiple NPV ORF5, but its function is unknown so far. The aim of this study is to characterize BmNPV ORF134 (Bm134).


METHODS
Transcription, protein expression and subcellular localization of Bm134 in BmN cells and silkworm midguts were analyzed using real-time polymerase chain reaction (RT-PCR), Western blot and immunofluorescence, respectively.


RESULTS
Both the transcription and protein expression of Bm134 were not detected until 24 h post-infection (p.i.) by RT-PCR and Western blot, indicating that Bm134 is a late gene. Western blot revealed that Bm134 encodes an expected 12.4-kDa structural protein that is associated with occlusion-derived virus (ODV), not with budded virus. Immunofluorescence analysis showed that the Bm134 was first detected in the cytoplasm 24 h p.i. and then transported to the nucleus during later infection. Transcripts of Bm134 and the corresponding protein were only detected 48-72 h p.i. in BmNPV-infected larvae of 306, a highly BmNPV-susceptible silkworm strain, but not in the NB strain that is resistant to BmNPV infection.


CONCLUSIONS
Taken together, our data suggest that Bm134 is a late gene of BmNPV and may function as an ODV structural protein.
Institute of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, PR China.
Feng
F
Lin
Keping
K
Chen
Hengchuan
H
Xia
Qin
Q
Yao
Lu
L
Gao
Huiqing
H
Chen
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D012831:Bombyx / Q000821:virology; D041981:Gastrointestinal Tract / Q000821:virology; D020869:Gene Expression Profiling; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D017924:Nucleopolyhedroviruses / Q000235:genetics*; D016366:Open Reading Frames; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D015678:Viral Structural Proteins / Q000096:biosynthesis
D015678:Viral Structural Proteins