This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Web of Science (31) Citing Articles via Google Scholar Google Scholar Articles by Meyer, Y. Articles by Chartier, Y. Search for Related Content PubMed PubMed Citation Articles by Meyer, Y. Articles by Chartier, Y. Agricola Articles by Meyer, Y. Articles by Chartier, Y.

Articles

Auxin-Induced Regulation of Protein Synthesis in Tobacco Mesophyll Protoplasts Cultivated In Vitro

I. Characteristics of Auxin-Sensitive Proteins

Laboratoire de Physiologie Végétale, Université de Perpignan, Avenue de Villeneuve, F-66025 Perpignan, France

The presence of auxin (2,4-D), in the culture medium of tobacco (Nicotiana tabacum var Maryland) mesophyll protoplasts is necessary both for cell wall regeneration and for passage of the cells from phase G₀ to phase G₁ of the cell cycle. Among about 250 proteins synthesized by protoplasts and characterized by their migration in a two-dimensional electrophoresis gel, 2,4-dichlorophenoxyacetic acid affects the synthesis of 11.

Nine proteins are synthesized at a reduced level in the presence of the hormone, of which three are rapidly labeled and short-lived, while the others, which are long-lived, become detectable only after 2 hours of radioactive labeling, suggesting that they undergo slow posttranslational maturation. These nine proteins are proline-rich but the proline radicals are not strongly hydroxylated. The synthesis of these proteins is no longer inhibited by auxin if dichlorobenzonitril, a weed-killer which inhibits cell wall reformation of tobacco protoplasts, is added to the culture medium.

Two proteins are only synthesized if protoplasts are cultivated in an auxin-containing medium. These polypeptides are rapidly labeled, and are long-lived. The inhibition of cell wall reformation by dichlorobenzonitril does not modify their synthesis.

These results suggest that proteins whose synthesis is reduced by auxin are related to cell wall reformation and that they do not play a role in the induction of the cell cycle. In contrast, proteins whose synthesis is stimulated in the presence of auxin are good candidates for a role in the induction of the cell cycle.

This article has been cited by other articles:

				M. A. Dong, J. L. Bufford, Y. Oono, K. Church, M. Q. Dau, K. Michels, M. Haughton, and G. Tallman Heat Suppresses Activation of an Auxin-Responsive Promoter in Cultured Guard Cell Protoplasts of Tree Tobacco Plant Physiology, October 1, 2007; 145(2): 367 - 377. [Abstract] [Full Text] [PDF]