Multiplicity of Cell Response to the BAI strain A (Myeloblastosis) Avian Tumor Virus. VI. Ultrastructural Aspects of Adenosinetriphosphatase Activity of Nephroblastoma Cells and Virus

Summary

Renal tumors with characteristics of nephroblastomas were induced in the chicken by inoculation of the BAI strain A avian tumor virus. Ultracy to chemical studies were made to determine the presence or absence of adenosinetriphosphatase in epithelial, sarcomatous, and chondromatous cellular components of the tumor, and of the enzyme associated with virus elaborated by the respective cells. Evidence of adenosinetriphosphatase was observed only at the brush border of cells corresponding to analogous elements of the proximal convoluted tubules of the normal nephron and at the membrane of cells resembling those of the distal convoluted tubule of the normal nephron. Virus budded from the membranes of the latter cells reacted positively for adenosinetriphosphatase. There was no reaction by virus associated with cells showing no enzyme at the cytoplasmic membrane. Virus in pellets sedimented from the blood plasma of chickens with myeloblastosis and treated with the same procedures gave a pronounced adenosinetriphosphatase reaction. The findings indicated that adenosinetriphospha tase in the virus in the nephroblastoma depended directly on incorporation of the enzyme into the particle as it budded from the membrane. The significance of the findings is discussed in relation to the influence of the respective host cells on the nature of the agent derived from them.