N-linked glycans of Bombyx mori nucleopolyhedrovirus fibroblast growth factor are crucial for its secretion.
Bombyx mori nucleopolyhedrovirus (BmNPV) fibroblast growth factor (BmFGF) is a glycosylated protein that is efficiently secreted into the medium. Here, we constructed mutant NPVs expressing His-tagged wild-type (wt) or mutant BmFGFs and showed that the two residues, asparagine 44 and 171, are the glycosylation sites of BmFGF. Also, removal of N-linked glycans from BmFGF resulted in almost complete inhibition of the secretion into the medium, suggesting that N-linked glycans of BmFGF are required for its secretion. These residues are not conserved in closely related Autographa californica NPV (AcMNPV)-encoded vFGF (AcFGF). Western blot analysis suggested that AcFGF is not glycosylated and is poorly secreted. A mutant AcFGF possessing two N-linked glycosylation sites was secreted into the medium more abundantly than that which occurred for wt AcFGF. This is the first direct evidence showing the role of N-linked glycans in the secretion process of a baculovirus protein.
Katsuma
Susumu
S
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. katsuma@ss.ab.a.u-tokyo.ac.jp
Daimon
Takaaki
T
Horie
Satoshi
S
Kobayashi
Michihiro
M
Shimada
Toru
T
D000595:Amino Acid Sequence; D000818:Animals; D012831:Bombyx / Q000821:virology*; D005346:Fibroblast Growth Factors / Q000737:chemistry* / Q000378:metabolism*; D008969:Molecular Sequence Data; D017924:Nucleopolyhedroviruses / Q000378:metabolism*; D011134:Polysaccharides / Q000737:chemistry* / Q000378:metabolism*
D011134:Polysaccharides; D005346:Fibroblast Growth Factors