PARP activity fine-tunes the DNA replication choreography of Chk1-depleted cells

PARP Inhibition Impedes the Maturation of Nascent DNA Strands During DNA Replication

10.1101/2021.07.03.450982 ◽

2021 ◽

Author(s):

Alina Vaitsiankova ◽

Kamila Burdova ◽

Hana Hanzlikova ◽

Keith Caldecott

Keyword(s):

Dna Replication ◽

Parp Inhibitor ◽

Parp Inhibitors ◽

Parp Inhibition ◽

Replication Forks ◽

Wild Type ◽

Potential Source ◽

Dna Strands ◽

Parp Activity ◽

Replication Intermediates

PARP1 is implicated in the detection and repair of unligated Okazaki fragment intermediates, highlighting these structures as a potential source of genome breakage induced by PARP inhibition. In agreement with this, we show here that PARP1 activity is greatly elevated in chicken and human S phase cells in which FEN1 nuclease is genetically deleted, and that PARP activity is highest tens of kilobases behind DNA replication forks. Importantly, PARP inhibitor reduces the integrity of nascent DNA strands in both wild type chicken and human cells during DNA replication, and does so in FEN1-/- cells to an even greater extent that can be detected as post-replicative single-strand gaps within individual DNA fibres. Collectively, these data show that PARP inhibitors impede the maturation of Okazaki fragments in nascent DNA, implicating these canonical DNA replication intermediates in the cytotoxicity of these compounds.

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Replication of Bacteriophage 186 DNA

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010009422x ◽

1972 ◽

Vol 30 ◽

pp. 194-195

Author(s):

Dhruba K. Chattoraj ◽

Ross B. Inman

Keyword(s):

Electron Microscopy ◽

Dna Replication ◽

Frame Of Reference ◽

Dna Molecules ◽

E Coli ◽

Phage Dna ◽

Partial Denaturation

Electron microscopy of replicating intermediates has been quite useful in understanding the mechanism of DNA replication in DNA molecules of bacteriophage, mitochondria and plasmids. The use of partial denaturation mapping has made the tool more powerful by providing a frame of reference by which the position of the replicating forks in bacteriophage DNA can be determined on the circular replicating molecules. This provided an easy means to find the origin and direction of replication in λ and P2 phage DNA molecules. DNA of temperate E. coli phage 186 was found to have an unique denaturation map and encouraged us to look into its mode of replication.

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