Localization with the Electron Microscope of p27 Rous Sarcoma Virus Internal Protein in Chicken Embryo Fibroblasts

Abstract

Protein 76 (Pr76), the precursor of the so-called ‘gag’ protein of avian leuko-sarcoma viruses, has been localized in the light and electron microscope by using the immunoperoxidase technique in Rous sarcoma virus-infected chick embryo fibroblasts. The kinetics of the progression of the protein through the cell was studied at different times after infection. The protein was first found (after 8 h) on ribosomes located near the nucleus and then proceeded rapidly to the periphery of the cell. After 5–6 days, intracytoplasmic staining faded away and only the ribosomes close to the plasma membrane were stained. A possible association of a protein with the cytoskeleton is suggested.

Intracellular Type A Retrovirus Movement Associated with an Intact Microtubule System

“…As production of viral proteins is not reduced under these experimental conditions, it may be concluded that an unperturbed microtubule system is necessary for the movement of viral proteins to the cell surface where virus particle assembly occurs (Satake & Luftig, 1982). Likewise, association of the p27 Rous sarcoma virus internal protein with microtubules has been suggested (Stanislawski, 1983). …”