Transcription from the adenovirus major late promoter uses redundant activating elements.

Reach, Michael; Xu, Long; Young, C. S. H.

doi:10.1002/j.1460-2075.1991.tb04908.x

Cited by 26 publications

(46 citation statements)

References 46 publications

(63 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3D). More efficient competition of the AdML promoter activity by the NF1 sequence may be due to titration of a factor which binds the CCAAT sequence present in the promoter (27). In general, since MREa is the only sequence capable of extreme effects on MT-IG activity, these results provide further support that MRE-binding factors are active in vitro.…”

Section: Effect Of Mrea and Tata Box Mutations On Mt-ig Promoter Actimentioning

confidence: 61%

Functional Analyses of the Human Metallothionein-IG Gene

Samson

Paramchuk

Shworak

et al. 1995

Journal of Biological Chemistry

View full text Add to dashboard Cite

We have analyzed the human (h) metallothionein (MT)-IG proximal promoter region (؊174 to ؉5) using a TATA box mutation (TATCA) and four trinucleotide mutants of the proximal MREa. Transient transfection of HepG2 cells was complemented by in vitro transcription with rat liver nuclear extracts. In both systems, mutations of the TATA box and conserved core of metal responsive element (MRE)a were detrimental to hMT-IG promoter activity suggesting that both elements make significant contributions to hMT-IG transcription. Although MRE binding factors were active in vitro, further metal activation of MT promoter activity was accomplished only by in vivo metal treatment rather than addition of zinc in vitro. Southwestern blotting identified nuclear proteins in rat liver and HepG2 cells which physically interact with MREa in a zinc-dependent manner and could be responsible for MREa function in each system. In addition, the functional effects of the TATCA mutation correlate with altered physical interaction with TATA box-binding protein as observed using DNase I protection. Metallothioneins (MTs)1 are low molecular mass (6 -7 kDa), cysteine-rich, metal-binding proteins which are thought to be important for trace metal homeostasis, as with zinc and copper, and detoxification, as with cadmium (1). Consistent with these putative functions, MTs are transcriptionally induced by these metals, mediated by multiple copies of metal-responsive elements (MREs) in the MT gene 5Ј-regulatory regions (2). MREs are 12-bp sequences which contain a heptanucleotide core sequence TGC(A/G)CNC surrounded by less conserved flanking nucleotides (2).We are interested in the regulation of the human (h)MT genes. This gene family consists of a minimum of 12 members which include both non-functional and processed pseudogenes as well as seven functional genes (3-5). The single MT-II isoform gene hMT-IIA is responsive to a variety of inducers including cytokines, growth factors, UV light, and glucocorticoids, and its regulatory region is complicated by numerous cis-acting elements which mediate the effects of such inducers (2). However, the promoters of the five hMT-I isoform genes are comparatively simple (3, 6) only containing MREs and GC boxes, which are possible binding sites for the SP1 transcription factor (3). Because of this simplicity, the hMT-I promoters are excellent candidates to study metal-regulated gene expression without complication by other inducible non-MRE elements as are found in hMT-IIA. Although the hMT-I promoters display remarkable homology of sequence and MRE organization (3), these genes exhibit cell type-specific patterns of expression as well as distinct levels of basal and metal-induced transcription within one cell type (3, 4).Previous studies of MRE contributions to transcription have employed synthetic MRE sequences fused to minimal promoters (7-9). However, we wished to examine MRE contributions to transcription regulation in the context of native MT promoter organization and sequences. For this purpose, we have chosen...

show abstract

Section: Effect Of Mrea and Tata Box Mutations On Mt-ig Promoter Actimentioning

confidence: 61%

Functional Analyses of the Human Metallothionein-IG Gene

Samson

Paramchuk

Shworak

et al. 1995

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

“…The basal ML promoter comprises a typical TATA sequence, an initiator, GC-rich sequences near the initiator, and binding sites for the cellular proteins USF and CBF located upstream of the TATA sequence (8,11,42,48,50,51,55). Late phase-specific stimulation of ML transcription in vitro and in infected cells requires additional, intragenic sequences, termed DE1 (positions ϩ86 to ϩ96) and DE2 (positions ϩ101 to ϩ116) (29, 34, 41).…”

mentioning

confidence: 99%

The Adenovirus L4 33-Kilodalton Protein Binds to Intragenic Sequences of the Major Late Promoter Required for Late Phase-Specific Stimulation of Transcription

Ali

LeRoy

Bridge

et al. 2007

J Virol

View full text Add to dashboard Cite

A characteristic feature of the infectious cycles of viruses with DNA genomes is DNA synthesis-dependent activation of transcription of viral late genes. In the case of human adenoviruses, such as adenovirus type 5 (Ad5), replication of the viral genome initiates a two-step transcriptional cascade. Transcription of the viral IVa 2 gene is first activated as a result of viral DNA synthesis-dependent titration of a cellular transcriptional repressor that binds to the IVa 2 promoter (10,27,36). Synthesis of the IVa 2 protein in infected cells then leads to maximally efficient transcription from the major late (ML) promoter, which controls expression of the coding sequences for all but one of the viral structural proteins (58). Entry into the late phase is accompanied by several changes in ML transcription. During the early phase, the ML and other early promoters are utilized with similar efficiencies (57), but ML transcription terminates at multiple sites within a large region in the middle of the transcription unit (1, 2, 28, 57). In contrast, termination occurs close to the right end of the viral genome during the late phase of infection (17). The difference in how much of the ML unit is transcribed, in conjunction with differences in the posttranscriptional processing of ML premRNAs, results in production of only the L1 52/55-kDa protein early in infection but at least 15 ML mRNAs late in infection (15,58). It has also been reported that the processivity of ML transcription beyond approximately position ϩ1,000 increases late in infection (33). Finally, the efficiency of ML transcription increases by a factor of 20 to 30 once viral DNA synthesis has commenced (57).The basal ML promoter comprises a typical TATA sequence, an initiator, GC-rich sequences near the initiator, and binding sites for the cellular proteins USF and CBF located upstream of the TATA sequence (8,11,42,48,50,51,55). Late phase-specific stimulation of ML transcription in vitro and in infected cells requires additional, intragenic sequences, termed DE1 (positions ϩ86 to ϩ96) and DE2 (positions ϩ101 to ϩ116) (29, 34, 41). These DE sequences are recognized by proteins present only in extracts of Ad5-infected cells harvested during the late phase of infection (29,34,44). Previous biochemical studies identified DEF-B, which binds to the DE2 sequence shown in Fig. 1, as a dimer of the IVa 2 protein (38,60). This interaction was shown to stimulate ML transcription in transient-expression assays (60). The DE1 and DE2a sequences of the ML promoter ( Fig. 1) are recognized by a second infected-cell-specific protein, termed DEF-A (30, 43). Initial efforts to purify DEF-A were not successful, although it was reported that the IVa 2 protein is also a component of this . In addition to binding to the ML promoter, the IVa 2 protein recognizes repeated, redundant sequences termed A repeats (20,21,56) within the viral packaging signal (65) and is required for packaging of the viral genome during assembly (46,66,67). This protein is a component of infected-cell-...

show abstract

“…In this case, TFIID could be brought to the promoter through proteinprotein interactions. It is noteworthy that two single base-pair changes in the TATA motif reduced but did not fully block the expression of properly initiated transcripts from the MLP in infected cells (21). Perhaps TFIID is brought to the promoter exclusively through its interaction with MAZ and Sp1 in this mutant virus.…”

Section: Discussionmentioning

confidence: 89%

Activation of the adenovirus major late promoter by transcription factors MAZ and Sp1

Parks

Shenk

1997

J Virol

View full text Add to dashboard Cite

Multiple binding sites for the transcription factors MAZ and Sp1 within the adenovirus type 5 major late promoter have been identified by DNase I protection studies. In the proximal region of the promoter, both MAZ and Sp1 interact with GC-rich sequences flanking the TATA box. Two MAZ binding sites are centered at ؊18 and ؊36 relative to the transcriptional initiation site. Sp1 bound only to the ؊18 GC-rich sequence. Several sites of interaction were also evident in the distal region of the promoter. Both MAZ and Sp1 interacted with a sequence centered at ؊166, and MAZ bound weakly to an additional site centered at ؊130. Overexpression of MAZ or Sp1 activated expression from the major late promoter in transient expression assays. Mutational analysis of the GC-rich sequences in the major late promoter suggested that a primary target of MAZ activation is the GC-rich sequences flanking the TATA sequence, whereas Sp1 requires the distal GC-rich sequence elements to stimulate gene expression. This activation is enhanced by the adenovirus E1A protein, and evidence for interaction between E1A and both transcription factors was obtained by using an immunoprecipitation assay. Activation by MAZ and Sp1 also was observed in transfection studies using the complete adenovirus type 5 genome as the target. Increased levels of late mRNA from both the L1 and L5 regions were observed when MAZ or Sp1 expression plasmids were transfected with viral DNA. Unexpectedly, activation of the major late promoter by MAZ and Sp1 was detected irrespective of whether the viral DNA could replicate.

show abstract

Transcription from the adenovirus major late promoter uses redundant activating elements.

Cited by 26 publications

References 46 publications

Functional Analyses of the Human Metallothionein-IG Gene

Functional Analyses of the Human Metallothionein-IG Gene

The Adenovirus L4 33-Kilodalton Protein Binds to Intragenic Sequences of the Major Late Promoter Required for Late Phase-Specific Stimulation of Transcription

Activation of the adenovirus major late promoter by transcription factors MAZ and Sp1

Contact Info

Product

Resources

About