BRCA1 represses DNA replication initiation through antagonizing estrogen signaling and maintains genome stability in parallel with WEE1–MCM2 signaling during pregnancy

The cell division cycle must be strictly regulated during both development and adult maintenance, and efficient and well-controlled DNA replication is a key event in the cell cycle. DNA replication origins are prepared in G1 phase of the cell cycle in a process known as origin licensing which is essential for DNA replication initiation in the subsequent S phase. Appropriate origin licensing includes: (1) Licensing enough origins at adequate origin licensing speed to complete licensing before G1 phase ends; (2) Licensing origins such that they are well-distributed on all chromosomes. Both aspects of licensing are critical for replication efficiency and accuracy. In this minireview, we will discuss recent advances in defining how origin licensing speed and distribution are critical to ensure DNA replication completion and genome stability.

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Genome duplication in Leishmania major relies on DNA replication outside S phase

10.1101/799429 ◽

2019 ◽

Author(s):

Jeziel D. Damasceno ◽

Catarina A. Marques ◽

Dario Beraldi ◽

Kathryn Crouch ◽

Craig Lapsley ◽

...

Keyword(s):

Cell Cycle ◽

Dna Replication ◽

Genome Stability ◽

Leishmania Major ◽

Genome Duplication ◽

S Phase ◽

Replication Initiation ◽

Dna Replication Initiation ◽

Synthesis Activity ◽

Important Parasite

AbstractOnce every cell cycle, DNA replication takes place to allow cells to duplicate their genome and segregate the two resulting copies into offspring cells. In eukaryotes, the number of DNA replication initiation loci, termed origins, is proportional to chromosome size. However, previous studies have suggested that in Leishmania, a group of single-celled eukaryotic parasites, DNA replication starts from just a single origin per chromosome, which is predicted to be insufficient to secure complete genome duplication within S phase. Here, we show that the paucity of origins activated in early S phase is balanced by DNA synthesis activity outside S phase. Simultaneous recruitment of acetylated histone H3 (AcH3), modified base J and the kinetochore factor KKT1 is exclusively found at the origins used in early S phase, while subtelomeric DNA replication can only be linked to AcH3 and displays persistent activity through the cell cycle, including in G2/M and G1 phases. We also show that subtelomeric DNA replication, unlike replication from the previously mapped origins, is sensitive to hydroxyurea and dependent on subunits of the 9-1-1 complex. Our work indicates that Leishmania genome transmission relies on an unconventional DNA replication programme, which may have implications for genome stability in this important parasite.

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FBL17 targets CDT1a for degradation in early S-phase to prevent Arabidopsis genome instability

10.1101/774109 ◽

2019 ◽

Author(s):

Bénédicte Desvoyes ◽

Sandra Noir ◽

Kinda Masoud ◽

María Isabel López ◽

Pascal Genschik ◽

...

Keyword(s):

Dna Replication ◽

Genome Stability ◽

Genome Instability ◽

S Phase ◽

Replication Initiation ◽

Genome Integrity ◽

Dependent Manner ◽

Dna Replication Initiation ◽

Oscillatory Pattern ◽

F Box Protein

AbstractMaintenance of genome integrity depends on controlling the availability of DNA replication initiation proteins, e.g., CDT1, a component of the pre-replication complexes that regulates chromatin licensing for replication. To understand the evolutionary history of CDT1 regulation, we have identified the mechanisms involved in CDT1 dynamics. During cell cycle, CDT1a starts to be loaded early after mitotic exit and maintains high levels until the G1/S transition. Soon after the S-phase onset, CDT1a is rapidly degraded in a proteasome-dependent manner. Plant cells use a specific SCF-mediated pathway that relies on the FBL17 F-box protein for CDT1a degradation, which is independent of CUL4a-containing complexes. A similar oscillatory pattern occurs in endoreplicating cells, where CDT1a is loaded just after finishing the S-phase. CDT1a is necessary to maintain genome stability, an ancient strategy although unique proteins and mechanisms have evolved in different eukaryotic lineages to ensure its degradation during S-phase.Impact statementThe DNA replication protein CDT1a is crucial for genome integrity and is targeted for proteasome degradation just after S-phase initiation by FBL17 in proliferating and endoreplicating cells of Arabidopsis

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A Novel Fluorescence-Based Screen for Inhibitors of the Initiation of DNA Replication in Bacteria

Current Drug Discovery Technologies ◽

10.2174/1570163815666180423115514 ◽

2019 ◽

Vol 16 (3) ◽

pp. 272-277 ◽

Cited By ~ 3

Author(s):

Rasmus N. Klitgaard ◽

Anders Løbner-Olesen

Keyword(s):

Dna Replication ◽

High Throughput ◽

Cyclic Peptide ◽

Replication Initiation ◽

False Positive Result ◽

Over Expression ◽

Initiator Protein ◽

Dna Replication Initiation ◽

Cellular Processes ◽

Initiation Of Dna Replication

Background:One of many strategies to overcome antibiotic resistance is the discovery of compounds targeting cellular processes, which have not yet been exploited.Materials and Methods:Using various genetic tools, we constructed a novel high throughput, cellbased, fluorescence screen for inhibitors of chromosome replication initiation in bacteria.Results:The screen was validated by expression of an intra-cellular cyclic peptide interfering with the initiator protein DnaA and by over-expression of the negative initiation regulator SeqA. We also demonstrated that neither tetracycline nor ciprofloxacin triggers a false positive result. Finally, 400 extracts isolated mainly from filamentous actinomycetes were subjected to the screen.Conclusion:We concluded that the presented screen is applicable for identifying putative inhibitors of DNA replication initiation in a high throughput setup.

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Changes in Chromosome Structure Regulate DNA Replication Initiation

Microbe Magazine ◽

10.1128/microbe.10.412.1 ◽

2015 ◽

Vol 10 (10) ◽

pp. 412-412

Keyword(s):

Dna Replication ◽

Chromosome Structure ◽

Replication Initiation ◽

Dna Replication Initiation

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Regulation of DNA Replication Licensing and Re-Replication by Cdt1

International Journal of Molecular Sciences ◽

10.3390/ijms22105195 ◽

2021 ◽

Vol 22 (10) ◽

pp. 5195

Author(s):

Hui Zhang

Keyword(s):

Cell Cycle ◽

Dna Damage ◽

Dna Replication ◽

Genome Stability ◽

E3 Ligase ◽

S Phase ◽

Replication Initiation ◽

Nuclear Antigen ◽

Repair Synthesis ◽

Ubiquitin E3 Ligase

In eukaryotic cells, DNA replication licensing is precisely regulated to ensure that the initiation of genomic DNA replication in S phase occurs once and only once for each mitotic cell division. A key regulatory mechanism by which DNA re-replication is suppressed is the S phase-dependent proteolysis of Cdt1, an essential replication protein for licensing DNA replication origins by loading the Mcm2-7 replication helicase for DNA duplication in S phase. Cdt1 degradation is mediated by CRL4Cdt2 ubiquitin E3 ligase, which further requires Cdt1 binding to proliferating cell nuclear antigen (PCNA) through a PIP box domain in Cdt1 during DNA synthesis. Recent studies found that Cdt2, the specific subunit of CRL4Cdt2 ubiquitin E3 ligase that targets Cdt1 for degradation, also contains an evolutionarily conserved PIP box-like domain that mediates the interaction with PCNA. These findings suggest that the initiation and elongation of DNA replication or DNA damage-induced repair synthesis provide a novel mechanism by which Cdt1 and CRL4Cdt2 are both recruited onto the trimeric PCNA clamp encircling the replicating DNA strands to promote the interaction between Cdt1 and CRL4Cdt2. The proximity of PCNA-bound Cdt1 to CRL4Cdt2 facilitates the destruction of Cdt1 in response to DNA damage or after DNA replication initiation to prevent DNA re-replication in the cell cycle. CRL4Cdt2 ubiquitin E3 ligase may also regulate the degradation of other PIP box-containing proteins, such as CDK inhibitor p21 and histone methylase Set8, to regulate DNA replication licensing, cell cycle progression, DNA repair, and genome stability by directly interacting with PCNA during DNA replication and repair synthesis.

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Candidate DNA replication initiation regions at human trinucleotide repeat disease loci

Human Molecular Genetics ◽

10.1093/hmg/ddg111 ◽

2003 ◽

Vol 12 (9) ◽

pp. 1021-1028 ◽

Cited By ~ 22

Author(s):

T. Nenguke

Keyword(s):

Dna Replication ◽

Trinucleotide Repeat ◽

Replication Initiation ◽

Dna Replication Initiation ◽

Disease Loci

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Archaeal Orc1 protein interacts with T-rich single-stranded DNA

BMC Research Notes ◽

10.1186/s13104-021-05690-w ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Katarzyna Wegrzyn ◽

Igor Konieczny

Keyword(s):

Dna Replication ◽

Replication Initiation ◽

Single Stranded Dna ◽

Dna Replication Initiation ◽

Double Stranded Dna ◽

Nucleoprotein Complexes ◽

Eukaryotic Organisms ◽

Replication Initiation Proteins ◽

Hydrolysis Of ◽

Replication Activity

Abstract Objective The ability to form nucleoprotein complexes is a fundamental activity of DNA replication initiation proteins. They bind within or nearby the region of replication origin what results in melting of a double-stranded DNA (dsDNA) and formation of single-stranded DNA (ssDNA) region where the replication machinery can assemble. For prokaryotic initiators it was shown that they interact with the formed ssDNA and that this interaction is required for the replication activity. The ability to interact with ssDNA was also shown for Saccharomyces cerevisiae replication initiation protein complex ORC. For Archaea, which combine features of both prokaryotic and eukaryotic organisms, there was no evidence whether DNA replication initiators can interact with ssDNA. We address this issue in this study. Results Using purified Orc1 protein from Aeropyrum pernix (ApOrc1) we analyzed its ability to interact with ssDNA containing sequence of an AT-rich region of the A. pernix origin Ori1 as well as with homopolymers of thymidine (polyT) and adenosine (polyA). The Bio-layer interferometry, surface plasmon resonance and microscale thermophoresis showed that the ApOrc1 can interact with ssDNA and it binds preferentially to T-rich ssDNA. The hydrolysis of ATP is not required for this interaction.

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DNA Content and Nucleoid Distribution in Methanothermobacter thermautotrophicus

Journal of Bacteriology ◽

10.1128/jb.187.5.1856-1858.2005 ◽

2005 ◽

Vol 187 (5) ◽

pp. 1856-1858 ◽

Cited By ~ 23

Author(s):

Alan I. Majerník ◽

Magnus Lundgren ◽

Paul McDermott ◽

Rolf Bernander ◽

James P. J. Chong

Keyword(s):

Flow Cytometry ◽

Dna Replication ◽

Chromosome Segregation ◽

Dna Content ◽

Replication Initiation ◽

Epifluorescence Microscopy ◽

Single Chromosome ◽

Dna Replication Initiation ◽

Methanothermobacter Thermautotrophicus ◽

Multiple Cells

ABSTRACT Flow cytometry and epifluorescence microscopy results for the euryarchaeon Methanothermobacter thermautotrophicus were consistent with filaments containing multiple cells. Filaments of one to four cells contained two to eight nucleoids. Single chromosome-containing cells were not observed. Filaments containing multiple genome copies displayed synchronous DNA replication initiation. Chromosome segregation occurred during replication or rapidly after replication termination.

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