Transcriptional activation by a DNA-tracking protein: Structural consequences of enhancement at the T4 late promoter

Tinker, Rachel L.; Williams, Kelly P.; Kassavetis, George A.; Geiduschek, E. Peter

doi:10.1016/0092-8674(94)90315-8

Cited by 67 publications

(82 citation statements)

References 35 publications

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“…It is anticipated that the two transcription-elevating interactions, AT-rich upstream DNA with the αCTD and the sliding clamp with the promoter complex, are mutually exclusive because they compete for space on the same DNA segment. This finding suggests that both linkages of the sliding clamp to the RNAP U -promoter complex through the C-ends of gp55 and gp33 are required to exclude the αCTDs from the DNA segment that is occupied by gp45 (Tinker et al, 1994b) or, possibly, to prevent a gp45-αCTD clash that results in misaligning gp45 with the promoter complex. Of course, this clash does not materialize in the normal phage multiplication cycle because of the attendant αCTD modification.…”

Section: Activation Sustained Solely By the Gp33-gp45 Interactionmentioning

confidence: 92%

“…Third, T4 late transcription in vivo is coupled to concurrent DNA replication through a unique transcriptional activator, the DNA-loaded sliding clamp, gp45 (Herendeen et al, 1992;Tinker et al, 1994a;Tinker et al, 1994b). Gp45, a head-to-tail trimer with a central annulus that is lined with positively charged side chains and accommodates double-stranded DNA, interacts with the similar acidic and hydrophobic C-terminal motifs of its ligands-gp55, gp33 and the T4 DNA polymerase gp43 ( Figure 1A) (Moarefi et al, 2000;Shamoo and Steitz, 1999;Trakselis et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

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Dissection of the Bacteriophage T4 Late Promoter Complex

Nechaev

Geiduschek

2008

Journal of Molecular Biology

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Activated transcription of the bacteriophage T4 late genes is generated by a mechanism that stands apart from the common modalities of transcriptional regulation: the activator gp45 is the viral replisome's sliding clamp; two sliding clamp-binding proteins, gp33 and gp55, replace the host RNA polymerase (RNAP) σ subunit. We have mutagenized, reconfigured and selectively disrupted individual interactions of the sliding clamp with gp33 and gp55 and have monitored effects on transcription. The C-terminal sliding clamp-binding epitopes of gp33 and gp55 are perfectly interchangeable, but the functions of these two RNAP-sliding clamp connections differ, with only the gp33-gp45 linkage essential for activation. Formation of transcription-ready promoter complexes by the sliding clamp-activated wild-type T4 RNAP resists competition by high concentrations of the polyanion heparin. This avid formation of promoter complexes requires both linkages of the T4 late RNAP to the sliding clamp. Preopening the promoter compensates for loss of the gp55-gp45 but not the gp33-gp45 linkage. We interpret these findings in relation to the common model of transcriptional initiation in bacteria and highlight the roles of individual interactions of the promoter complex.

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Section: Activation Sustained Solely By the Gp33-gp45 Interactionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Dissection of the Bacteriophage T4 Late Promoter Complex

Nechaev

Geiduschek

2008

Journal of Molecular Biology

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“…Although the clamps were first discovered for their use in replication, it soon became apparent that they are also involved in many other DNA metabolic processes. The first example of this was in the T4 system in which Geiduschek and coworkers demonstrated that the T4 gp45 clamp can act as a ''mobile enhancer'' to activate transcription of phage late genes (9). This work demonstrated that T4 gp45 assembles onto DNA at a nicked site and interacts with phage-modified E. coli RNA polymerase, which is then active for specific transcription from the phage late-gene promoters.…”

Section: Pcna and Gp45 Participate In Many Dna Metabolic Processesmentioning

confidence: 99%

Interaction of the β sliding clamp with MutS, ligase, and DNA polymerase I

Saro

O'Donnell

2001

Proc. Natl. Acad. Sci. U.S.A.

212

203

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The ␤ and proliferating cell nuclear antigen (PCNA) sliding clamps were first identified as components of their respective replicases, and thus were assigned a role in chromosome replication. Further studies have shown that the eukaryotic clamp, PCNA, interacts with several other proteins that are involved in excision repair, mismatch repair, cellular regulation, and DNA processing, indicating a much wider role than replication alone. Indeed, the Escherichia coli ␤ clamp is known to function with DNA polymerases II and V, indicating that ␤ also interacts with more than just the chromosomal replicase, DNA polymerase III. This report demonstrates three previously undetected protein-protein interactions with the ␤ clamp. Thus, ␤ interacts with MutS, DNA ligase, and DNA polymerase I. Given the diverse use of these proteins in repair and other DNA transactions, this expanded list of ␤ interactive proteins suggests that the prokaryotic ␤ ring participates in a wide variety of reactions beyond its role in chromosomal replication. PCNA ͉ mismatch repairThe Sliding Clamp in Replication

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“…After assembly around circular plasmid DNA, PCNA could be crosslinked to the DNA. Upon linearization of the plasmid, however, PCNA could no longer be crosslinked to the template, suggesting it has sliding properties (Tinker et al, 1994). Experiments similar to these used to demonstrate the sliding of the E. coli b subunit were performed with human PCNA.…”

Section: Structurementioning

confidence: 99%

“…These results suggested that PCNA could thread itself onto the end of the dsDNA molecule and slide along the duplex until it reached the 3' end, where it interacted with Pold to initiate processive DNA synthesis. Crosslinking experiments were used in a dierent strategy to demonstrate the sliding property of PCNA (Tinker et al, 1994). After assembly around circular plasmid DNA, PCNA could be crosslinked to the DNA.…”

Section: Structurementioning

confidence: 99%

PCNA: structure, functions and interactions

1997

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Proliferating cell nuclear antigen (PCNA) plays an essential role in nucleic acid metabolism as a component of the replication and repair machinery. This toroidalshaped protein encircles DNA and can slide bidirectionally along the duplex. One of the wellestablished functions for PCNA is its role as the processivity factor for DNA polymerase d and e. PCNA tethers the polymerase catalytic unit to the DNA template for rapid and processive DNA synthesis. In the last several years it has become apparent that PCNA interacts with proteins involved in cell-cycle progression which are not a part of the DNA polymerase apparatus. Some of these interactions have a direct eect on DNA synthesis while the roles of several other interactions are not fully understood. This review summarizes the structural features of PCNA and describes the diverse functions played by the protein in DNA replication and repair as well as its possible role in chromatin assembly and gene transcription. The PCNA interactions with dierent cellular proteins and the importance of these interactions are also discussed.

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Transcriptional activation by a DNA-tracking protein: Structural consequences of enhancement at the T4 late promoter

Cited by 67 publications

References 35 publications

Dissection of the Bacteriophage T4 Late Promoter Complex

Dissection of the Bacteriophage T4 Late Promoter Complex

Interaction of the β sliding clamp with MutS, ligase, and DNA polymerase I

PCNA: structure, functions and interactions

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