Molecular characterization of tomato fruit polygalacturonase

Sheehy, Raymond E.; Pearson, Judith A.; Brady, Colin J.; Hiatt, William R.

doi:10.1007/bf00330418

Cited by 108 publications

(50 citation statements)

References 24 publications

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“…However, searching the SWISS-PROT database revealed that the Cryj II amino acid sequence shares a significant homology with polygalacturonases (PGs), especially that derived from tomato, Lycopersicon esculentum (40% identity, Fig. 2) [14,15], from Zea mays (34% identity) [16,17], and that from Oenothera organensis (34% identity) [18].…”

Section: Resultsmentioning

confidence: 99%

Molecular cloning of the second major allergen, Cry j II, from Japanese cedar pollen

et al. 1994

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Section: Resultsmentioning

confidence: 99%

Molecular cloning of the second major allergen, Cry j II, from Japanese cedar pollen

et al. 1994

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“…Recent evidence suggests that the differences in glycosylation between PG2A and PG2B result from differences in cotranslational core glycosylation rather than from differential processing of the glycan side chains (DellaPenna and Bennett, 1988). Comparison of the amino acid sequence of mature PG2A and PG2B with the amino acid sequence deduced from cDNA clones further indicates at least two additional proteolytic processing steps, one that removes 47 amino acids following the signal sequence (DellaPenna and Bennett, 1988), and another that removes 13 amino acids from the C terminus of the precursor protein (Sheehy et al, 1987). Both of these proteolytic events are presumed to occur post-translationally, although the subcellular sites of these cleavages and whether they occur in one or in multiple steps are not known.…”

Section: Resultsmentioning

confidence: 99%

Analysis of tomato polygalacturonase expression in transgenic tobacco.

et al. 1990

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Tomato polygalacturonase is a cell wall enzyme secreted in large amounts during tomato fruit ripening. Polygalacturonase is synthesized as a glycoprotein precursor that undergoes numerous cotranslational and post-translational processing steps during its maturation, yielding three isozymes in tomato fruit, PG1, PGPA, and PGPB. To investigate the physiological roles of the three isozymes and the functional significance of the polygalacturonase processing domains in its intracellular transport and activity, we have examined polygalacturonase expression in transgenic tobacco plants. A full-length polygalacturonase cDNA was placed under control of the cauliflower mosaic virus 35s promoter and introduced into tobacco by way of Agrobacterium-mediated transformation. Analysis of transgenic tobacco plants indicated that (1) immunologically detectable polygalacturonase can be extracted from leaves, roots, and stems of transgenic tobacco plants; ( 2 ) only PGSA and PGPB were detectable in transgenic tobacco; (3) the polygalacturonase isozymes present in transgenic tobacco were electrophoretically indistinguishable from the tomato isozymes; (4) the N-terminal sequence, degree of N-linked glycosylation, and extent of oligosaccharide processing were similar in polygalacturonase from transgenic tobacco and tomato; (5) polygalacturonase was properly localized in cell walls of transgenic tissue; (6) the protein was enzymically active in vitro; however, (7) accumulation of PGPA and PGSB in cell walls of transgenic tobacco did not result in pectin degradation in vivo. These results indicated that tomato polygalacturonase was properly processed and transported to the cell wall of tobacco. However, accumulation of the two polygalacturonase isozymes expressed in this heterologous host was insufficient to promote polyuronide degradation in tobacco leaf tissue.

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“…Among the ripening-associated enzymes studied in tomato, the cell wall-degrading enzyme polygalacturonase has been analyzed in the greatest detail (2,4,5,8,9,12,13,(24)(25)(26). The site of action of polygalacturonase is the cell wall, where it hydrolyzes polyuronides, or pectins.…”

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Polygalacturonase Isozymes and Pectin Depolymerization in Transgenic rin Tomato Fruit

DellaPenna¹,

Lashbrook²,

Toenjes³

et al. 1990

Plant Physiol.

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We have previously described the construction and expression of a chimeric gene that allows developmentally regulated expression of tomato (Lycopersicon esculentum) polygalacturonase in ripening-impaired, mutant (rin) tomato fruit (JJ Giovannoni, D DellaPenna, AB Bennett, The Plant Cell 1: 53-63). We now show that expression of the chimeric polygalacturonase gene in rin tomato fruit resulted in the accumulation of all three polygalacturonase isozymes (PG1, PG2A, and PG2B). Polyuronide solubilization and polyuronide depolymerization both reached their maximal levels in transgenic rin fruit prior to the appearance of PG2 isozymes. These results demonstrate that PG1, PG2A, and PG2B all arise by differential processing of a single gene product and further suggest that the PG1 isozyme is sufficient to carry out both polyuronide solubilization and depolymerization in vivo.Tomato fruit ripening is characterized by a number of coordinated biochemical and physiological changes, which collectively alter fruit color, flavor, and texture. Biochemical and genetic analysis (6, 7) has indicated that many of the physiological processes associated with ripening are regulated at the level of gene expression, a view firmly supported by recent analysis ofgene expression during tomato fruit ripening (1,8,11,14,17,28).Among the ripening-associated enzymes studied in tomato, the cell wall-degrading enzyme polygalacturonase has been analyzed in the greatest detail (2,4,5,8,9,12,13,(24)(25)(26). The site of action of polygalacturonase is the cell wall, where it hydrolyzes polyuronides, or pectins. The increase in the level of chelator-soluble polyuronides during ripening and their corresponding decrease in molecular size have been well documented and are attributed to the action of polygalacturonase (15,22,23). Polygalacturonase activity isolated from ripe fruit is comprised of three closely related isozymes, PGl, PG2A, and PG2B (4,5,10,(18)(19)(20)

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Molecular characterization of tomato fruit polygalacturonase

Cited by 108 publications

References 24 publications

Molecular cloning of the second major allergen, Cry j II, from Japanese cedar pollen

Molecular cloning of the second major allergen, Cry j II, from Japanese cedar pollen

Analysis of tomato polygalacturonase expression in transgenic tobacco.

Polygalacturonase Isozymes and Pectin Depolymerization in Transgenic rin Tomato Fruit

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