The adenovirus E1A N-terminal repression domain represses transcription from a chromatin template in vitro

Abstract

The adenovirus repression domain of E1A 243R at the E1A N-terminus (E1A 1–80) transcriptionally represses genes involved in differentiation and cell cycle progression. E1A 1–80 represses transcription in vitro from naked DNA templates through its interaction with p300 and TFIID. E1A 1–80 can also interact with several chromatin remodeling factors and associates with chromatin in vivo. We show here that E1A 243R and E1A 1–80 can repress transcription from a reconstituted chromatin template in vitro. Temporal analysis reveals strong repression by E1A 1–80 when added at pre-activation, activation and early transcription stages. Interestingly, E1A 1–80 can greatly enhance transcription from chromatin templates, but not from naked DNA, when added at pre-initiation complex (PIC) formation and transcription-initiation stages. These data reveal a new dimension for E1A 1–80's interface with chromatin and may reflect its interaction with key players in PIC formation, p300 and TFIID, and/or possibly a role in chromatin remodeling.

The adenovirus E1A oncoprotein N-terminal transcriptional repression domain enhances p300 autoacetylation and inhibits histone H3 Lys18 acetylation

“…Since transcription and histone acetylation occur in the context of chromatin, we examined the effect of E1A 1-80 on histone acetylation in reconstituted chromatin. Chromatin was assembled using purified core histone, ATP-dependent chromatin assembly factors, and the transcription template pG5MLT [ 2 , 28 ]. The E1A 1-80-repressible pG5MLT template contains the core Ad ML (Major Late) promoter downstream of five copies of the Gal4-binding site that allow transcriptional activation by Gal4-VP16.…”

“…In contrast, normal cells are not killed by E1A 1-80. Since chromatin is the natural template for transcriptional regulation, we have recently examined E1A-mediated transcriptional repression in reconstituted chromatin, and found that transcription from an E1A-repressible template in chromatin is effectively repressed by E1A 1-80 and E1A 243R [ 2 ].…”

“… Expression of the adenovirus E1A N-terminal transcription repression domain alone (E1A 1-80) represses transcription from specific promoters such as HER2 [ 1 ] and from reconstituted chromatin [ 2 ]. Significantly, E1A 1-80 can induce the death of human breast cancer cells over-expressing the HER2 oncogene [ 1 ] as well as other cancer cells.…”

Homologous recombination-based adenovirus vector system for tumor cell-specific gene delivery

“…E1a, a well-known tumor suppressor gene, is the first viral gene expressed during adenovirus infection. 17,18 The multiple functions of E1A include transcriptional activation, induction of cellular DNA synthesis, cell transformation, antitumor activities and sensitization to different categories of antitumor drugs. [19][20][21] Therefore, enhanced HRAVS (EHRAVS) that consists of Ad.IR.…”

Expression of Adenoviral E1A in Transformed Cells as an Additional Factor of HDACi-Dependent FoxO Regulation

“…E1A expression is essential for viral replication, since E1A stimulates progression from the gap 1 (G1) to synthesis (S) phase, allowing the virus to use host cell replication machinery. E1A gene products participate in the regulation of DNA synthesis, transcription, cell immortalization, and transformation [3].…”