SYNTHESIS AND LOCALIZATION OF SYMBIONIN, AND APHID ENDOSYMBIONT PROTEIN

In an effort to know the function of symbionin, and aphid endosymbiont -specific protein homologous to Escherichia coli GroEL protein, its sy nthesis and localization in the host insect were investigated. Microau toradiography of the tissue sections revealed that symbionin is synthe sized and localized exclusively in the bacteriocyte. Immunohistochemis try with anti-symbionin antiserum suggested also that symbionin is pre sent only in the bacteriocyte, especially concentrated in the endosymb iont. Immunohistochemistry of the semi-ultrathin tissue sections demon strated that symbionin is localized in the endosymbiont and not detect ed in the cytoplasm of the bacteriocyte. These results indicated that symbionin is synthesized, localized, and functions in the endosymbiont , suggesting that it functions for the endosymbiont's own sake rather than for the host insect.