scholarly journals Genetic evidence for reconfiguration of DNA polymerase θ active site for error-free translesion synthesis in human cells

2020 ◽  
Vol 295 (18) ◽  
pp. 5918-5927
Author(s):  
Jung-Hoon Yoon ◽  
Robert E. Johnson ◽  
Louise Prakash ◽  
Satya Prakash

The action mechanisms revealed by the biochemical and structural analyses of replicative and translesion synthesis (TLS) DNA polymerases (Pols) are retained in their cellular roles. In this regard, DNA polymerase θ differs from other Pols in that whereas purified Polθ misincorporates an A opposite 1,N6-ethenodeoxyadenosine (ϵdA) using an abasic-like mode, Polθ performs predominantly error-free TLS in human cells. To test the hypothesis that Polθ adopts a different mechanism for replicating through ϵdA in human cells than in the purified Pol, here we analyze the effects of mutations in the two highly conserved tyrosine residues, Tyr-2387 and Tyr-2391, in the Polθ active site. Our findings that these residues are indispensable for TLS by the purified Pol but are not required in human cells, as well as other findings, provide strong evidence that the Polθ active site is reconfigured in human cells to stabilize ϵdA in the syn conformation for Hoogsteen base pairing with the correct nucleotide. The evidence that a DNA polymerase can configure its active site entirely differently in human cells than in the purified Pol establishes a new paradigm for DNA polymerase function.

2015 ◽  
Vol 29 (24) ◽  
pp. 2588-2602 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
Jeseong Park ◽  
Juan Conde ◽  
Maki Wakamiya ◽  
Louise Prakash ◽  
...  

Translesion synthesis (TLS) DNA polymerases (Pols) promote replication through DNA lesions; however, little is known about the protein factors that affect their function in human cells. In yeast, Rev1 plays a noncatalytic role as an indispensable component of Polζ, and Polζ together with Rev1 mediates a highly mutagenic mode of TLS. However, how Rev1 functions in TLS and mutagenesis in human cells has remained unclear. Here we determined the role of Rev1 in TLS opposite UV lesions in human and mouse fibroblasts and showed that Rev1 is indispensable for TLS mediated by Polη, Polι, and Polκ but is not required for TLS by Polζ. In contrast to its role in mutagenic TLS in yeast, Rev1 promotes predominantly error-free TLS opposite UV lesions in humans. The identification of Rev1 as an indispensable scaffolding component for Polη, Polι, and Polκ, which function in TLS in highly specialized ways opposite a diverse array of DNA lesions and act in a predominantly error-free manner, implicates a crucial role for Rev1 in the maintenance of genome stability in humans.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Olga Rechkoblit ◽  
Robert E. Johnson ◽  
Yogesh K. Gupta ◽  
Louise Prakash ◽  
Satya Prakash ◽  
...  

AbstractPrimPol is a human DNA polymerase-primase that localizes to mitochondria and nucleus and bypasses the major oxidative lesion 7,8-dihydro-8-oxoguanine (oxoG) via translesion synthesis, in mostly error-free manner. We present structures of PrimPol insertion complexes with a DNA template-primer and correct dCTP or erroneous dATP opposite the lesion, as well as extension complexes with C or A as a 3′−terminal primer base. We show that during the insertion of C and extension from it, the active site is unperturbed, reflecting the readiness of PrimPol to accommodate oxoG(anti). The misinsertion of A opposite oxoG(syn) also does not alter the active site, and is likely less favorable due to lower thermodynamic stability of the oxoG(syn)•A base-pair. During the extension step, oxoG(syn) induces an opening of its base-pair with A or misalignment of the 3′-A primer terminus. Together, the structures show how PrimPol accurately synthesizes DNA opposite oxidatively damaged DNA in human cells.


2018 ◽  
Vol 8 (2) ◽  
pp. 754-754
Author(s):  
Likui Zhang ◽  
Yanchao Huang ◽  
Xinyuan Zhu ◽  
Yuxiao Wang ◽  
Haoqiang Shi ◽  
...  

Biomolecules ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 648
Author(s):  
del Prado ◽  
Santos ◽  
Lázaro ◽  
Salas ◽  
de Vega

Bacteriophage Phi29 DNA polymerase belongs to the protein-primed subgroup of family B DNA polymerases that use a terminal protein (TP) as a primer to initiate genome replication. The resolution of the crystallographic structure showed that it consists of an N-terminal domain with the exonuclease activity and a C-terminal polymerization domain. It also has two subdomains specific of the protein-primed DNA polymerases; the TP Regions 1 (TPR1) that interacts with TP and DNA, and 2 (TPR2), that couples both processivity and strand displacement to the enzyme. The superimposition of the structures of the apo polymerase and the polymerase in the polymerase/TP heterodimer shows that the structural changes are restricted almost to the TPR1 loop (residues 304–314). In order to study the role of this loop in binding the DNA and the TP, we changed the residues Arg306, Arg308, Phe309, Tyr310, and Lys311 into alanine, and also made the deletion mutant Δ6 lacking residues Arg306–Lys311. The results show a defective TP binding capacity in mutants R306A, F309A, Y310A, and Δ6. The additional impaired primer-terminus stabilization at the polymerization active site in mutants Y310A and Δ6 allows us to propose a role for the Phi29 DNA polymerase TPR1 loop in the proper positioning of the DNA and TP-priming 3’-OH termini at the preinsertion site of the polymerase to enable efficient initiation and further elongation steps during Phi29 TP-DNA replication.


2017 ◽  
Vol 8 (2) ◽  
pp. 754-754
Author(s):  
Likui Zhang ◽  
Yanchao Huang ◽  
Xinyuan Zhu ◽  
Yuxiao Wang ◽  
Haoqiang Shi ◽  
...  

2016 ◽  
Vol 45 (3) ◽  
pp. 1270-1280 ◽  
Author(s):  
Leticia K. Lerner ◽  
Guilherme Francisco ◽  
Daniela T. Soltys ◽  
Clarissa R.R. Rocha ◽  
Annabel Quinet ◽  
...  

1991 ◽  
Vol 11 (9) ◽  
pp. 4786-4795
Author(s):  
J S Gibbs ◽  
K Weisshart ◽  
P Digard ◽  
A deBruynKops ◽  
D M Knipe ◽  
...  

Most DNA polymerases are multifunctional proteins that possess both polymerizing and exonucleolytic activities. For Escherichia coli DNA polymerase I and its relatives, polymerase and exonuclease activities reside on distinct, separable domains of the same polypeptide. The catalytic subunits of the alpha-like DNA polymerase family share regions of sequence homology with the 3'-5' exonuclease active site of DNA polymerase I; in certain alpha-like DNA polymerases, these regions of homology have been shown to be important for exonuclease activity. This finding has led to the hypothesis that alpha-like DNA polymerases also contain a distinct 3'-5' exonuclease domain. We have introduced conservative substitutions into a 3'-5' exonuclease active site homology in the gene encoding herpes simplex virus DNA polymerase, an alpha-like polymerase. Two mutants were severely impaired for viral DNA replication and polymerase activity. The mutants were not detectably affected in the ability of the polymerase to interact with its accessory protein, UL42, or to colocalize in infected cell nuclei with the major viral DNA-binding protein, ICP8, suggesting that the mutation did not exert global effects on protein folding. The results raise the possibility that there is a fundamental difference between alpha-like DNA polymerases and E. coli DNA polymerase I, with less distinction between 3'-5' exonuclease and polymerase functions in alpha-like DNA polymerases.


2016 ◽  
Vol 30 (2) ◽  
pp. 669-677 ◽  
Author(s):  
Paritosh Pande ◽  
Shaofei Ji ◽  
Shivam Mukherjee ◽  
Orlando D. Schärer ◽  
Natalia Y. Tretyakova ◽  
...  

2020 ◽  
Vol 48 (15) ◽  
pp. 8461-8473
Author(s):  
Rachel Bezalel-Buch ◽  
Young K Cheun ◽  
Upasana Roy ◽  
Orlando D Schärer ◽  
Peter M Burgers

Abstract DNA polymerase ζ (Pol ζ) and Rev1 are essential for the repair of DNA interstrand crosslink (ICL) damage. We have used yeast DNA polymerases η, ζ and Rev1 to study translesion synthesis (TLS) past a nitrogen mustard-based interstrand crosslink (ICL) with an 8-atom linker between the crosslinked bases. The Rev1–Pol ζ complex was most efficient in complete bypass synthesis, by 2–3 fold, compared to Pol ζ alone or Pol η. Rev1 protein, but not its catalytic activity, was required for efficient TLS. A dCMP residue was faithfully inserted across the ICL-G by Pol η, Pol ζ, and Rev1–Pol ζ. Rev1–Pol ζ, and particularly Pol ζ alone showed a tendency to stall before the ICL, whereas Pol η stalled just after insertion across the ICL. The stalling of Pol η directly past the ICL is attributed to its autoinhibitory activity, caused by elongation of the short ICL-unhooked oligonucleotide (a six-mer in our study) by Pol η providing a barrier to further elongation of the correct primer. No stalling by Rev1–Pol ζ directly past the ICL was observed, suggesting that the proposed function of Pol ζ as an extender DNA polymerase is also required for ICL repair.


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