The beta subunit of the Escherichia coli DNA polymerase III holoenzyme interacts functionally with the catalytic core in the absence of other subunits.

LaDuca, R J; Crute, James J.; McHenry, Charles S.; Bambara, Robert A.

doi:10.1016/s0021-9258(17)38427-2

Cited by 68 publications

(14 citation statements)

References 27 publications

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“…6). The presence of b stimulates DNA Pol III activity, increasing product length and processivity (60). In agreement with this, we observed a reduction of template molecules with full-length, nascent leading strands and a decrease in total DNA synthesis at lower concentrations of b.…”

Section: Discussionsupporting

confidence: 88%

“…This form of uncoupling is therefore a common event during DNA synthesis. The b sliding clamp enhances DNA polymerase III processivity and increases product length (60,61). In single molecule experiments, median burst synthesis length decreased and median pause length increased when the concentration of b was reduced, suggesting that under these conditions gap formation increased.…”

Section: Two Components Of Dna Replication-dependent Lexa Cleavagementioning

confidence: 99%

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Two components of DNA replication-dependent LexA cleavage

Myka

Marians

2020

Journal of Biological Chemistry

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Induction of the SOS response, a cellular system triggered by DNA damage in bacteria, depends on DNA replication for the generation of the SOS signal, single-stranded DNA. RecA binds to single-stranded DNA, forming filaments that stimulate proteolytic cleavage of the LexA transcriptional repressor, allowing expression of > 40 gene products involved in DNA repair and cell cycle regulation. Here, using a DNA replication system reconstituted in vitro in tandem with a LexA cleavage assay, we studied LexA cleavage during DNA replication of both undamaged and base-damaged templates. Only a single-stranded DNA–RecA filament supported LexA cleavage. Surprisingly, replication of an undamaged template supported levels of LexA cleavage similar to that induced by a template carrying two site-specific cyclobutane pyrimidine dimers. We found that two processes generate single-stranded DNA that could support LexA cleavage. 1) During unperturbed replication, single-stranded regions formed because of stochastic uncoupling of the leading-strand DNA polymerase from the replication fork DNA helicase, and 2) on the damaged template, nascent leading-strand gaps were generated by replisome lesion skipping. The two pathways differed in that RecF stimulated LexA cleavage during replication of the damaged template, but not normal replication. RecF appears to facilitate RecA filament formation on the leading-strand single-stranded DNA gaps generated by lesion skipping.

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Section: Discussionsupporting

confidence: 88%

Section: Two Components Of Dna Replication-dependent Lexa Cleavagementioning

confidence: 99%

Two components of DNA replication-dependent LexA cleavage

Myka

Marians

2020

Journal of Biological Chemistry

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“…Replisome skipping of leading-strand blockages to DNA replication requires continued procession of the DNA helicase, DnaB and the lagging-strand polymerase downstream of the lesion, albeit at a reduced speed, so that a ss gap can be created to expose DnaG priming sites on the leading-strand template ( 48 ). Thus, factors that should affect the efficiency of replisome skipping include reduction of the concentration of the β clamp and of DnaG, which will thereby reduce the processivity of the DNA Polymerase III Holoenzyme ( 49–51 ), and the frequency of leading-strand priming ( 48 , 52 ), respectively. Neither of these factors should affect mRNA takeover.…”

Section: Resultsmentioning

confidence: 99%

Bypass of complex co-directional replication-transcription collisions by replisome skipping

Brüning

Marians

2021

Nucleic Acids Research

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Collisions between the replisome and RNA polymerases [RNAP(s)] are the main obstacle to DNA replication. These collisions can occur either head-on or co-directionally with respect to the direction of translocation of both complexes. Whereas head-on collisions require additional factors to be resolved, co-directional collisions are thought to be overcome by the replisome itself using the mRNA transcript as a primer. We show that mRNA takeover is utilized primarily after collisions with single RNAP complexes with short transcripts. Bypass of more complex transcription complexes requires the synthesis of a new primer downstream of the RNAP for the replisome to resume leading-strand synthesis. In both cases, bypass proceeds with displacement of the RNAP. Rep, Mfd, UvrD and RNase H can process the RNAP block and facilitate replisome bypass by promoting the formation of continuous leading strands. Bypass of co-directional RNAP(s) and/or R-loops is determined largely by the length of the obstacle that the replisome needs to traverse: R-loops are about equally as potent obstacles as RNAP arrays if they occupy the same length of the DNA template.

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“…Reactions were terminated by addition of 25 mL of 200 mM EDTA. DNA was prepared for scintillation counting as described (LaDuca et al, 1986).…”

mentioning

confidence: 99%

Carbonyldiphosphonate, a selective inhibitor of mammalian DNA polymerase .delta.

Talanian

Brown²,

McKenna³

et al. 1989

Biochemistry

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Twenty-three pyrophosphate analogues were screened as inhibitors of proliferating cell nuclear antigen independent DNA polymerase delta (pol delta) derived from calf thymus. Carbonyldiphosphonate (COMDP), also known as alpha-oxomethylenediphosphonate, inhibited pol delta with a potency (Ki = 1.8 microM) 20 times greater than that displayed for DNA polymerase alpha (pol alpha) derived from the same tissue. Characterization of the mechanism of inhibition of pol delta indicated that COMDP competed with the dNTP specified by the template and was not competitive with the template-primer. In the case of pol alpha, COMDP did not compete with either the dNTP or the polynucleotide substrate. COMDP inhibited the 3'----5' exonuclease activity of pol delta weakly, displaying an IC50 greater than 1 mM.

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The beta subunit of the Escherichia coli DNA polymerase III holoenzyme interacts functionally with the catalytic core in the absence of other subunits.

Cited by 68 publications

References 27 publications

Two components of DNA replication-dependent LexA cleavage

Two components of DNA replication-dependent LexA cleavage

Bypass of complex co-directional replication-transcription collisions by replisome skipping

Carbonyldiphosphonate, a selective inhibitor of mammalian DNA polymerase .delta.

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