Characterization of the baculovirus Bombyx mori nucleopolyhedrovirus gene homologous to the mammalian FGF gene family.
We characterized a gene of the baculovirus Bombyx mori nucleopolyhedrovirus (BmNPV) homologous to the mammalian fibroblast growth factor (FGF) family. We termed it vfgf, and examined its transcription and the properties of the gene product (vFGF). RT-PCR analysis showed that vfgf is one of the baculovirus early genes, although there are no consensus sequences of the baculovirus early gene promoters. 5'-RACE analysis revealed that its transcription started at 10 nucleotides upstream of the translation start codon. vFGF has a hydrophobic amino terminus (approximately 16 amino acids), which is a typical signal sequence. As expected, vFGF was efficiently secreted from BmNPV-infected BmN cells. Because possible glycosylation sites are found at positions 44 (Asn) and 171 (Asn), we examined whether BmNPV vFGF is glycosylated or not. Cleavage of recombinant vFGF with PNGase F revealed that BmNPV vFGF was glycosylated. We also found that secretion of vFGF is completely blocked by the treatment of Tunicamycin, which blocks N-linked glycosylation. This is the first report to characterize a virus-encoded FGF.
Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan.
Susumu
S
Katsuma
Toru
T
Shimada
Masahiko
M
Kobayashi
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D012831:Bombyx / Q000821:virology*; D002478:Cells, Cultured; D005346:Fibroblast Growth Factors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D017924:Nucleopolyhedroviruses / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*
D014764:Viral Proteins; D005346:Fibroblast Growth Factors