TY - JOUR
T1 - Antisense expression of chaperonin 60β in transgenic tobacco plants leads to abnormal phenotypes and altered distribution of photoassimilates
AU - Zabaleta, Eduardo
AU - Oropeza, Araceli
AU - Assad, Nacyra
AU - Mandel, Alejandra
AU - Salerno, Graciela
AU - Herrera-Estrella, Luis
PY - 1994
Y1 - 1994
N2 - Chaperonins are a class of molecular chaperone, present in bacteria, mitochondria and chloroplasts, that are involved in protein folding and assembly in many organisms. Plastid α and β chaperonins have been suggested to be involved specifically in the assembly of Ribulose bisphosphate carboxylase/oxygenase. However, to date there is no direct evidence to confirm the in vivo role of plastid chaperonin 60 polypeptides as molecular chaperones. This paper reports on the production, by means of antisense technology, of transgenic tobacco plants with reduced levels of chaperonin 60β (Cpn60β). Antisense cpn60β plants showed drastic phenotypic alterations including slow growth, delayed flowering, stunting and leaf chlorosis. The most extreme effect appeared to be lethality suggesting that cpn60β functions are essential for viability. Cpn60β antisense plants accumulated Rubisco to specific activities equal to or higher than that of controls and had high plastid starch contents. These observations are discussed with respect to the suggestion that chaperonin is required for the assembly of active Rubisco in vivo. In addition, metabolic alterations in the antisense transgenic plants such as reduced soluble carbohydrate content as well as higher levels of starch in chloroplasts, suggest that Cpn60β may be required for import, assembly or membrane insertion of several chloroplast membrane proteins. These results are in agreements with the proposed role of Cpn60β as a molecular chaperone.
AB - Chaperonins are a class of molecular chaperone, present in bacteria, mitochondria and chloroplasts, that are involved in protein folding and assembly in many organisms. Plastid α and β chaperonins have been suggested to be involved specifically in the assembly of Ribulose bisphosphate carboxylase/oxygenase. However, to date there is no direct evidence to confirm the in vivo role of plastid chaperonin 60 polypeptides as molecular chaperones. This paper reports on the production, by means of antisense technology, of transgenic tobacco plants with reduced levels of chaperonin 60β (Cpn60β). Antisense cpn60β plants showed drastic phenotypic alterations including slow growth, delayed flowering, stunting and leaf chlorosis. The most extreme effect appeared to be lethality suggesting that cpn60β functions are essential for viability. Cpn60β antisense plants accumulated Rubisco to specific activities equal to or higher than that of controls and had high plastid starch contents. These observations are discussed with respect to the suggestion that chaperonin is required for the assembly of active Rubisco in vivo. In addition, metabolic alterations in the antisense transgenic plants such as reduced soluble carbohydrate content as well as higher levels of starch in chloroplasts, suggest that Cpn60β may be required for import, assembly or membrane insertion of several chloroplast membrane proteins. These results are in agreements with the proposed role of Cpn60β as a molecular chaperone.
UR - http://www.scopus.com/inward/record.url?scp=0028057089&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:0028057089
SN - 0960-7412
VL - 6
SP - 425
EP - 432
JO - Plant Journal
JF - Plant Journal
IS - 3
ER -