SPECIFIC EXPRESSION OF CELLULAR ONCOGENES C-MYC AND C-MYB IN T-CELL LINES ESTABLISHED FROM 3 TYPES OF BOVINE LYMPHOSARCOMAS

Expression of cellular oncogenes in 3 lymphoid cell lines, BTL-PC3 (Bo CD2(-), BoCD4(-), BoCD8(-), BoWC1(+)), BLT1 (BoCD2(+), BoCD4(-), BoCD8 (-), BoWC1(-)) and BLT2 (BoCD2(-), BoCD4(-), BoCD8(-), BoWC1(-)), whic h have been established from calf, skin, and thymic types of lymphosar comas, respectively, were analyzed by DNA-RNA (northern blot) hybridiz ation. To determine specific expression of oncogenes involved in malig nant transformation of the lymphoid cells, cellular RNA was isolated f rom bovine tumor cell lines, BTL-PC3, BLS1, and BLT2, and from Madin D arby bovine kidney cells used as a control for bovine cell lines. The RNA was hybridized against 5 viral oncogene probes (v-jun, v-myc, v-er bB, v-erbA and v-fes), 6 human cellular oncogene probes (N-ras, c-Blym -1 c-erbB-2, c-fos, c-myb and c-abl), human p53 tumor suppressor gene, and bovine LDH-A gene probes. Line BTL-PCS expressed 2.4-kilobase (kb ) c-myc and 4.0- and 3.6-kb c-myb transcripts, and line BLT2 expressed a 3.8-kb c-myb transcript, but line BLS1 expressed no message for the oncogenes tested. Specific transcripts of p53 were found in BTL-PC3 a nd BLT2 lines, but not in BLS1. Madin Darby bovine kidney cell line ex pressed multiple cellular oncogenes, c-jun, c-myc, and c-fos, and p53 genes. Southern blot hybridization did not reveal abnormal DNA rearran gements associated with the expressed oncogenes (c-myc and c-myb) in t he 3 bovine tumor lines. From these results and the immunophenotype of the lymphoid cells, it appeared that c-myb specific mRNA were transcr ibed more often in immature bovine leukemia T cells (calf and thymic t ypes) than in mature T cells from the skin type.