Correct processing of the kiwifruit protease actinidin in transgenic tobacco requires the presence of the C-terminal propeptide.
A 355 cauliflower mosaic virus promoter and a tapetum-specific promoter were used to direct the synthesis in tobacco of preproactinidin and a derivative that lacked a C-terminal extension. Preproactinidin was processed into a form that migrated identically on protein gels with mature actinidin extracted from kiwifruit. This protein was proteolytically active in vitro, and high-level accumulation of this protein appeared to be detrimental to plant growth. Plants expressing an actinidin cDNA construct that lacked the sequence encoding the C-terminal propeptide were phenotypically normal but accumulated N-proactinidin, which was proteolytically active in vitro but did not self-cleave to mature actinidin. In transgenic tobacco, the C-terminal extension of actinidin is therefore required for correct processing.
Paul
W
W
Department of Botany, Leicester University, United Kingdom.
Amiss
J
J
Try
R
R
Praekelt
U
U
Scott
R
R
Smith
H
H
D001483:Base Sequence; D003546:Cysteine Endopeptidases / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D017931:DNA Primers; D018076:DNA, Complementary; D004792:Enzyme Precursors / Q000096:biosynthesis / Q000378:metabolism*; D005638:Fruit / Q000201:enzymology* / Q000235:genetics; D015870:Gene Expression; D007700:Kinetics; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D011499:Protein Processing, Post-Translational; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D015183:Restriction Mapping; D014026:Nicotiana
D017931:DNA Primers; D018076:DNA, Complementary; D004792:Enzyme Precursors; D011993:Recombinant Fusion Proteins; D003546:Cysteine Endopeptidases; C018745:actinidain