Two tumor antigens and their polypeptides in adenovirus type 12-infected and transformed cells

Abstract

A tumor (T) antigen, designated T antigen g, was visualized as fine fluorescent granules in nuclei of adenovirus type 12 (Adl2)infected cells by immunofluorescence with sera from rats bearing HY cell tumors (H sera). HY cells are rat cells incompletely transformed by the Acc I-H endonuclease fragment (0-4.7 map units) of Adl2 DNA. The antigen is different from the usually described T antigen, designated T antigen f, which is visualized as fluorescent flecks or filaments in both nucleus and cytoplasm of Adl-infected (17). With the background described above, we once again tried to detect antibody in sera from rats bearing HY cell tumors. We used indirect immunofluorescence, in which Adl2-infected cells were stained with rat sera, followed by dye-conjugated anti-rat IgG. After examination of many rat sera, we found that a small number of sera stained the antigen in Adl2-infected cells. However, the morphology of the antigen (tentatively named T antigen g) was different from that of T antigen (tentatively named T antigen f) reported until now (2, 3). It was fluorescent granules confined to the nucleus, in contrast to fluorescent flecks or filaments in the nucleus and cytoplasm. We concluded that the new T antigen must be different from the classic T antigen of Adl2.On the basis of this finding, we tried to identify T antigen polypeptides with the use of sera from hamsters bearing tumors or sera from rats bearing CY 2274The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U. S. C. §1734 solely to indicate this fact.

Adenovirus-Cell Interactions Early After Infection: In vitro Characteristics and Tumourigenicity of Adenovirus Type 2-transformed Rat Liver Epithelial Cells

“…The 60K protein is probably the phosphorylated single-stranded DNA binding protein previously described (Rosenwirth et aI., 1975;Jochemsen et aL, 1980). The 8K protein is similar as seen by two-dimensional gel electrophoresis (data not shown) to the 10K protein which Shiroki et al (1980) have reported to be located between the map position 4-7 and 6.8 on the Ad-12 chromosome. They also reported that this low mol.…”

“…The flecked fluorescence we observed in Ad-12-infected C3 cells is, therefore, in agreement with their observations. The 8K protein may have certain properties resembling the 10K protein of Shiroki et al (1980) but we have only been able to immunoprecipitate the 8K protein from transformed cells containing the whole Ad-12 genome, and not from those containing only the left-hand 16.5% or less of the Ad-12 genome (C. Paraskeva et al, unpublished results). Therefore, these two proteins may well not be identical.…”

Identification of adenovirus 12-encoded E1A tumor antigens synthesized in infected and transformed mammalian cells and in Escherichia coli

“…The conclusion that the immunoprecipitated proteins are the Adl2 ElA T antigens is supported by: (i) the specific inhibition of the immunoprecipitation reaction by peptide 204; (ii) the apparent Mr of 45K to 47K which is similar to that observed for Ad2-, AdS-, and Adl2-encoded ElA T antigens (4,8,15,19,20,26,30,33); (iii) the characteristic acidic isoelectric point observed by two-dimensional gel electrophoresis; (iv) the phosphorylation of the proteins immunoprecipitated from Adl2-infected and -transformed mammalian cells (8,33); (v) the immunofluorescent staining of Adl2-infected KB cells by antipeptide 204 antibody, with the specificity of the staining being confirmed by the blocking of immunofluorescence with peptide 204; and (vi) the fluorescence associated with the nucleus, since a nuclear localization of ElA protein has been suggested by cell fractionation and immunofluorescence studies (6,11,27,33).…”

Neoplastic transformation of rat 3Y1 cells by a transcriptionally activated human c-myc gene and stabilization of p53 cellular tumor antigen in the transformed cells.

“…Antigenantibody complexes were collected by centrifugation after adsorption onto S. aureus. The precipitates were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) as described previously (21,37,41). Monoclonal antibody 401 was used as a control.…”