Patent ID: 6140075
Filing Date: 2000-10-31
Classification: C07K,C12N

Abstract:
A method for obtaining secretable plant protein toxins from plant cells, comprising the steps of:providing a DNA construct comprising a selectable marker and, in 5' to 3' order, a promoter that promotes transcription in tobacco cells in cell culture, a plant sequence that encodes a peptide that directs secretion of a protein from the tobacco cells, a DNA sequence that encodes a secretable heterologous plant protein toxin, and a transcription terminator functional in tobacco cells;transforming tobacco suspension cells with the DNA construct;selecting for transgenic tobacco cells in which the selectable marker gene of the DNA construct is expressed;culturing the transgenic tobacco cells in a liquid suspension culture under condition such that the secretable protein toxin encoded by the DNA construct accumulates in the liquid culture to a concentration of greater than 25 mg/l, the accumulated mammalian single chain antibody comprising more than 10% of the total secreted protein in the medium; andisolating the accumulated protein toxin away from the tobacco cells.