Transformation Defective E1a-Products of the Ad12-Non-Oncogenic Host Range Mutant Cs-1 Are Able to Disrupt E2f-Containing Complexes and to Transactivate E2f-Motif Containing Promoters

Abstract

ESSEN MEDICAL SCHOOL, HWELAND STR. 55,45122 ESSEN, FRG, essende ABSTRACT The transformation defective Vero-cell host range mutant CS-I of the highly omgenic denoviruS type 12 (Adl2) has a 69 bp deletion in the EIA gene that nmoves the carboxyterminal half of the conserved ngion 2 andtheaminotaminalhelfoftheM12spccific~calledspacerthatsams to play a pivotal role in the onw@nicity of the virus. Despite its Mliency evidence that the EIA 13s protein of CS-I ntaios the activity to bind the "pocket" proteins plOS', p107 as well as p130 in nuclear extract binding assays using GST-EIA-fusion proteins and western blot analysis. In comparison to wild type E1A the mutant EIA protein is able to disnqt E2F containing nuclear complexes as judged from gel-shif~ experiments with purified 12s and 13s EIA proteins, after transfection with an EIAexpression vector or infection with the respeaivc virus. Moteover, in traolsicnt cxpnssion assays the 13s EIA protein from both, Ad12 WT and CS-I mutant was shown to transactlv ' ate thc distal W r proximal promoter of Adl2, recently shown to contain cooperating E2F-1-and An-motifs or au EZF-S-Iike-motif, rcspcctively, in a comparable manuer. The same nsults wen obtained from Inusfedon assays using other typical E2F-motif containing promoters, like the Ads E2 or the human Qhydrofolatc duaase promoter. These data suggest that e&cient infection by the oncogenic Ad12 and the comlated virus-iduccd reproglammiq of the infected cells, including induction of cell cycle relevant mechaoisms (c.g. E2F-activation)