Protein Synthesis in Adenovirus E1A Transformed Cells

Abstract

Protein synthesis in cells transformed by the E1A gene of adenovirus type 12 (Ad 12) was investigated using rat fibroblast cells (3Y1), these cells transformed by the E1A gene of Ad 12 (HY1), human epithelial carcinoma cells (KB) and their transformant (KB-E1A), and mouse mammary tumor cells (FM3A) and their transformant (FM3A-E1A). The proteins labeled with (³²S)-methionine in the intact cells or synthesized using an in vitro translation system were analyzed by two dimensional gel electrophoresis.
The E1A gene of Adl2 increased the number of protein spots in the gel. On the other hand, TPA (12-O-tetradecanoyl-phorbol-13-acetate) increased the number of protein spots in 3Y1 cells while TPA did not seem to have the same effect in HY1 cells. In vitro translation of the mRNAs from 3Y1, HY1, KB, and KB-E1A cells have shown that the number of protein spots in the gel were greater in the E1A-transformed cells than non-transformed cells.
FM3A cells transformed by the E1A gene of Ad 12 drastically suppressed their induction of interferon as compared with that in FM3A cells.
Since E1A gene encodes for proteins, it is suggested that the proteins are trans-acting components (enhancers or suppressors) at the level of transcription of cellular genes as well as viral genes and consequently protein synthesis is affected in the transformed cells.