Transformation-associated proteins in murine B-cell lymphomas that are distinct from Abelson virus gene products.

Abstract

In an effort to identify cellular proteins that may be involved in the Abelson murine leukemia virus (A-MuLV) transformation process, a hybridoma antibody (6C3) that detects a tumor-associated antigen in all A-MuLV-induced pre-B-cell lymphomas was isolated. The 6C3 antibody immunoprecipitates 2 molecules of MW 160,000 and MW 125,000 from metabolically labeled A-MuLV tumors. The 2 proteins recognized by the 6C3 antibody are distinct from the A-MuLV-transforming protein in that they lack viral gag determinants and are neither phosphoproteins nor protein kinases. The 6C3 proteins can be detected in all A-MuLV pre-B-cell lymphomas and some nonviral B lymphomas but are not detected on any other tumor or normal cell, including A-MuLV-transformed fibroblast lines. Thus, the 6C3 proteins may represent the products of novel cellular genes whose expression is induced, stabilized or amplified in B-cell tumors of both viral and nonviral origin. Evidently, 6C3 antigen expression correlates with autonomous cell growth and the transformed phenotype in both normal bone marrow cultures and those infected with A-MuLV.