文摘
Specific proteins of symbiosis were analyzed by the comparison of two-dimensional electrophoresis protein patterns of symbiotic and aposymbiotic strains of the weevilSitophilus oryzae.One protein was shown to be exclusively expressed in the aposymbiotic strain and three proteins, including a chaperonin, were characterized in the symbiotic strain pattern. ThegroE-like operon, encoding the two chaperonins groES and GroEL-like proteins of the endocytobiotes, was sequenced. It was found to be very similar to thegroEoperon ofEscherichia coli(82 % identity).In vitroandex vivoexperiments of protein labelling demonstrated that almost 40 % of the endocytobiote protein synthesisex vivois focused on the GroEL-like protein. Finally, we showed by northern blotting that heat shock at 38°C results ingroELmRNA accumulation inside the endocytobiotes. This work supports the hypothesis that chaperonins could have an essential physiological function in the maintenance of the symbiotic association.