Isolation and properties of the inclusion bodies of cauliflower mosaic virus.

In an attempt to isolate new gene products of cauliflower mosaic virus a procedure was developed for isolation of the cytoplasmic inclusion bodies induced by the virus. Two types of inclusions, the relative ratios of which vary with virus strain, were obtained. One type was the native, vacuolated inclusion encountered in sections of tissue observed with the electron microscope. It contains virus particles. A second, granular type of inclusion body is devoid of virus. It consists wholly of electron-dense material that resembles the matrix material of the native inclusion body. Granular inclusions consist of a single 55,000-dalton protein which is also a major constituent of the native vacuolated type. This protein is not antigenically related to the virus.