Human DNA polymerase delta (Polδ), a holoenzyme consisting of p125, p50, p68, and p12 subunits, plays an essential role in DNA replication, repair, and recombination. Herein, using multiple physicochemical and cellular approaches, we found that the p12 protein forms a dimer in solution. In vitro reconstitution and pull down of cellular Polδ by tagged p12 substantiate the pentameric nature of this critical holoenzyme. Furthermore, a consensus proliferating nuclear antigen (PCNA) interaction protein motif at the extreme carboxyl-terminal tail and a homodimerization domain at the amino terminus of the p12 subunit were identified. Mutational analyses of these motifs in p12 suggest that dimerization facilitates p12 binding to the interdomain connecting loop of PCNA. In addition, we observed that oligomerization of the smallest subunit of Polδ is evolutionarily conserved as Cdm1 of also dimerizes. Thus, we suggest that human Polδ is a pentameric complex with a dimeric p12 subunit, and discuss implications of p12 dimerization in enzyme architecture and PCNA interaction during DNA replication.
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http://dx.doi.org/10.26508/lsa.201900323 | DOI Listing |
FEBS Lett
December 2024
Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India.
Dysregulation of human DNA polymerase delta (Polδ) subunits is associated with genome instability and pathological disorders. Genome databases suggest the expression of several spliced variants of subunits which may alter Polδ function. Here, we analyzed the protein-encoding variants of the Polδ subunit p12 and their association with cancer.
View Article and Find Full Text PDFRom J Morphol Embryol
July 2024
Department of Genetics, Genomic Medicine Centre, Department of Pediatrics, Victor Babeş University of Medicine and Pharmacy, Timişoara, Romania;
Acute lymphoblastic leukemia (ALL) is the most common type of leukemia in childhood and rare in adults, while acute myeloid leukemia (AML) is less common in children and more common in older adults. The aim of the study was to present our experience for the diagnostic of leukemia by using the classic and molecular cytogenetic methods. The study was conducted between 2009 and 2019 within the Classic and Molecular Genetic Laboratory of the Oncohematology Department from the Louis Ţurcanu Emergency Hospital for Children, Timişoara, Romania.
View Article and Find Full Text PDFCancer Genomics Proteomics
November 2023
Section for Cancer Cytogenetics, Institute for Cancer Genetics and Informatics, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway.
Background/aim: Angioleiomyoma is a benign tumor, occurs at any age, and arises most frequently in the lower extremities. Genetic information on angioleiomyomas is restricted to six reported abnormal karyotypes, losses in chromosome 22 and gains in Xq found by comparative genomic hybridization, and mutation analysis of notch receptor 2 (NOTCH2), NOTCH3, platelet-derived growth factor receptor beta (PDGFRB), and mediator complex subunit 12 (MED12) in a few tumors. Herein, we report the genetic findings in another three angioleiomyomas.
View Article and Find Full Text PDFDNA Repair (Amst)
August 2023
Department of Biochemistry and Molecular Biology, New York Medical College, 15 Dana Road, Valhalla, NY 10595, USA. Electronic address:
The extension of the invading strand within a displacement loop (D-loop) is a key step in homology directed repair (HDR) of doubled stranded DNA breaks. The primary goal of these studies was to test the hypotheses that 1) D-loop extension by human DNA polymerase δ4 (Pol δ4) is facilitated by DHX9, a 3' to 5' motor helicase, which acts to unwind the leading edge of the D-loop, and 2) the recruitment of DHX9 is mediated by direct protein-protein interactions between DHX9 and Pol δ4 and/or PCNA. DNA synthesis by Pol δ4 was analyzed in a reconstitution assay by the extension of a 93mer oligonucleotide inserted into a plasmid to form a D-loop.
View Article and Find Full Text PDFGenes (Basel)
March 2023
Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, IN 46202, USA.
DNA polymerase delta is the primary polymerase that is involved in undamaged nuclear lagging strand DNA replication. Our mass-spectroscopic analysis has revealed that the human DNA polymerase δ is acetylated on subunits p125, p68, and p12. Using substrates that simulate Okazaki fragment intermediates, we studied alterations in the catalytic properties of acetylated polymerase and compared it to the unmodified form.
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