Two functions encoded by adenovirus early region 1A are responsible for the activation and repression of the DNA-binding protein gene.

on sequences located in the upstream region (approximately -40 to -250) of these promoters. In addition, we showed that the major late and Ella late upstream promoter regions do not contain such Ela-responsive sequence elements. In contrast, after transfection of these chimeric promoter recombinants into 293 cells (which constitutively express the Eta proteins), we found that their relative levels of transcription are similar and markedly different from those observed when they are cotransfected into HeLa cells with Eta protein-producing recombinants. We conclude that the efficiency of transcription from a given promoter in 293 cells is not necessarily related to the presence of a specific Ela-responsive element.

Section: Resultssupporting

confidence: 90%

Sequence-specific activation of transcription by adenovirus EIa products is observed in HeLa cells but not in 293 cells.

Leff¹,

Chambon²

1986

“…These include adenovirus ElA protein (2,5,16,22,23,26,30,33,34,43,44,49,59,62,64), the adenovirus E2A protein (15), the SV40 early protein, T antigen (6), and several herpesvirus early gene products (9,14,28,30,45,46,47). Also, several retroviruses including Rous sarcoma virus (8) and HTLV (55,56) code for proteins that are trans activators of viral gene expression via the viral long terminal repeat sequences.…”

Section: Resultsmentioning

confidence: 99%

Negative and positive regulation in trans of gene expression from adeno-associated virus vectors in mammalian cells by a viral rep gene product.

Tratschin¹,

Tal²,

Carter³

1986

149

143

We previously described use of the human parvovirus, adeno-associated virus (AAV), as a vector for transient expression in mammalian cells of the gene for chloramphenicol acetyltransferase (CAT). In the AAV vector, pTS1, the CAT gene is expressed under the control of the major AAV promoter p4o. This The human parvovirus, adeno-associated virus (AAV), replicates in mammalian cells in the presence of helper functions provided by adenovirus or herpesvirus (10). When molecular clones containing the entire AAV type 2 (AAV2) genome in bacterial plasmids are transfected into mammalian cells in the presence of adenovirus, the AAV genome is excised from the plasmid and replicated to produce infectious AAV particles (38,50,52). This facilitated both the genetic analysis of AAV (27,(51)(52)(53)59) and the development of AAV as a eucaryotic expression vector (26,60,61).The AAV genome contains three transcription promoters, P5, Pi9, and P40, which yield overlapping transcripts (11). Genetic analysis showed that a major AAV reading frame (orf-2) which is accessible from P40 transcripts codes for a major portion of the AAV capsid proteins (27,59). Mutations in this region (cap-) allow normal synthesis of duplex replicating form DNA but prevent synthesis of progeny single-stranded DNA and infectious particles (27,53,59). A second major open reading frame (orf-1) in the left half of the genome is apparently accessible from either p5 or P19 transcripts and codes for one or more proteins (rep) required for AAV DNA replication (27,53,59). Mutations in this region (rep-) are DNA negative but can be complemented. Deletion of both terminal palindromes results in a cis-dominant (ori-) defect which reflects the presence of the AAV replication origins in the terminal repeat sequences (3,4,25,51,53).

“…Studies of morphological effects on 3T3 cells expressing 13S ElA products with multiple mutations also suggest that the conserved domains of the ElA gene encode separate functions (31). These functions may include gene regulation by repression, since the 12S product has been shown to suppress expression from the late promoter of the adenovirus E2A gene (19) and both the 12S and 13S products have been shown to suppress the action of enhancers (5,24,68). Impairment of the ability to suppress the action of enhancers appears to colTelate with impairment of the transformation function resulting from mutations in domain 2 of the 12S ElA product (36).…”

Section: Discussionmentioning

confidence: 99%

Different functional domains of the adenovirus E1A gene are involved in regulation of host cell cycle products.

Zerler¹,

Roberts²,

Mathews³

et al. 1987

176

141

We have analyzed the ceH cycle effects that different domains of the adenovirus EIA proteins have on quiescent primary BRK cells. Studies with deletion mutants that in combination removed all but the N-terminal 85 amino acids common to both the 12S and 13S proteins suggest that this region may be sufficient for the induction of synthesis of proliferating cell nuclear antigen and the stimulation of DNA synthesis. A second domain also common to the N-terminal exon of the 12S and 13S proteins was required for the induction of mitosis and stimulation of proliferation of primary BRK cells. A virus containing a mutation in this region was still able to stimulate DNA synthesis efficiently. A third domain, unique to the 13S protein, was required for the accelerated activation of the cellular thymidylate synthase gene in a manner similar to the 13S-dependent stimulation of adenovirus early region genes.