To understand cellular events and biochemical mechanisms involved in cell transformation, we will focus on a single viral protein, the human adenovirus (Ad) ElA 243R oncoprotein. We will study (i) the collective functions of 243R in modulating (activating or repressing) expression of cellular genes that may be involved in oncogene cooperation and cell immortalization and (ii) the individual biochemical functions of 243R in transcriptional repression and the induction of cellular DNA synthesis. The hypothesis that ElA 243R modulates expression of critical cellular genes will be investigated. It will be determined whether expression of subsets of """"""""primary response"""""""" genes (rapidly activated when quiescent cells are induced to proliferate) and """"""""late response"""""""" genes are induced by introduction of EIA 243R into quiescent cells. To identify previously unrecognized cellular genes regulated by ElA 243R, hybridization enriched cDNA libraries from mRNA populations expressed early after ElA introduction into quiescent cells will be analyzed. To determine whether cellular genes modulated by ElA are """"""""primal genes"""""""" whose overexpression is essential and sufficient for ElA oncogene cooperation and/or immortalization, cDNA clones under control of a strong constitutive promoter will be assayed in baby rat kidney cells. To study ElA 243R transcriptional repression and cellular DNA induction functions, essential ElA domains will be clarified and attempts made to synthesize biologically active, minimal domain ElA peptides. It will be determined whether these minimal ElA peptides induce a subset of cellular genes modulated by native ElA 243R. To distinguish between models of ElA repression, a novel cell microinjection assay will be used to determine whether de novo protein synthesis is required for repression. To provide functional assays for cellular proteins that associate with ElA 243R functional domains and that may play a role in repression or DNA induction, attempts will be made to develop in vitro repression and cell complementation assays.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Research Project (R01)
Project #
Application #
Study Section
Virology Study Section (VR)
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Saint Louis University
Schools of Medicine
Saint Louis
United States
Zip Code
Loewenstein, Paul M; Wu, Shwu-Yuan; Chiang, Cheng-Ming et al. (2012) The adenovirus E1A N-terminal repression domain represses transcription from a chromatin template in vitro. Virology 428:70-5
Loewenstein, Paul M; Green, Maurice (2011) Expression of the Adenovirus Early Gene 1A Transcription-Repression Domain Alone Downregulates HER2 and Results in the Death of Human Breast Cancer Cells Upregulated for the HER2 Proto-Oncogene. Genes Cancer 2:737-44
Green, Maurice; Panesar, Ninder K; Loewenstein, Paul M (2008) Adenovirus E1A proteins are closely associated with chromatin in productively infected and transformed cells. Virology 371:1-7
Green, M; Panesar, N K; Loewenstein, P M (2008) The transcription-repression domain of the adenovirus E1A oncoprotein targets p300 at the promoter. Oncogene 27:4446-55
Green, Maurice; Thorburn, Andrew; Kern, Robert et al. (2007) The use of cell microinjection for the in vivo analysis of viral transcriptional regulatory protein domains. Methods Mol Med 131:157-86
Loewenstein, Paul M; Song, Chao-Zhong; Green, Maurice (2007) The use of in vitro transcription to probe regulatory functions of viral protein domains. Methods Mol Med 131:15-31
Loewenstein, Paul M; Arackal, Sophia; Green, Maurice (2006) Mutational and functional analysis of an essential subdomain of the adenovirus E1A N-terminal transcription repression domain. Virology 351:312-21
Boyd, Janice M; Loewenstein, Paul M; Tang Qq, Qing-quan et al. (2002) Adenovirus E1A N-terminal amino acid sequence requirements for repression of transcription in vitro and in vivo correlate with those required for E1A interference with TBP-TATA complex formation. J Virol 76:1461-74
Song, C Z; Loewenstein, P M; Toth, K et al. (1997) The adenovirus E1A repression domain disrupts the interaction between the TATA binding protein and the TATA box in a manner reversible by TFIIB. Mol Cell Biol 17:2186-93
Song, C Z (1996) Requirement for phosphorylation of RNA polymerase II C-terminal domain in transcription is both transcript length and promoter dependent. Biochem Biophys Res Commun 229:810-6

Showing the most recent 10 out of 24 publications