Expression, glycosylation and secretion of phaseolin in a baculovirus system. Academic Article uri icon


  • In this report, we describe the efficient expression and glycosylation, in insect cells, of -phaseolin polypeptides (M r 45 and 48 kDa) from Phaseolus vulgaris, by means of a baculovirus expression vector. N-terminal sequence analysis demonstrated that the signal peptide was efficiently processed. Tunicamycin treatment suppressed both phaseolin bands seen in untreated or control cells, and resulted in a single species (M r 43 kDa). We provide evidence that the observed size heterogeneity arises by asymmetric glycosylation of a single, high-molecular weight precursor. These results also indicate that differential glycosylation of phaseolin polypeptides can occur on the product of a single gene, and, in that sense, is not dependent on amino acid sequence variations. Phaseolin accumulates to a very high level (90 g/10(6) cells), 90% of it being secreted into the culture medium. Immuno-gold staining and electron microscopy demonstrated phaseolin polypeptides in electron-dense, membrane-bound vesicles seen at the periphery of the cytoplasm of infect cells and in cytoplasmic multivesicular bodies. The effect on protein accumulation of a single-basepair transversion (GC) at position +6 is also described. This study constitutes, to our knowledge, one of the first instances of a plant protein being expressed in insect cells and suggests possible differences in the sorting mechanisms of glycoproteins from legume seeds and those from Spodoptera frugiperda cell line Sf9.

published proceedings

  • Plant Mol Biol

altmetric score

  • 3

author list (cited authors)

  • Bustos, M. M., Luckow, V. A., Griffing, L. R., Summers, M. D., & Hall, T. C.

citation count

  • 38

complete list of authors

  • Bustos, MM||Luckow, VA||Griffing, LR||Summers, MD||Hall, TC

publication date

  • November 1988