scholarly journals Replication origins drive genetic and phenotypic variation in humans

2021 ◽  
Author(s):  
Pierre Murat ◽  
Guillaume Guilbaud ◽  
Julian E Sale

DNA replication starts with the activation of the replicative helicases, polymerases and associated factors at thousands of origins per S-phase. Due to local torsional constraints generated during licensing and the switch between polymerases of distinct fidelity and proofreading ability following firing, origin activation has the potential to induce DNA damage and mutagenesis. However, whether sites of replication initiation exhibit a specific mutational footprint has not yet been established. Here we demonstrate that mutagenesis is increased at early and highly efficient origins. The elevated mutation rate observed at these sites is caused by two distinct mutational processes consistent with formation of DNA breaks at the origin itself and local error-prone DNA synthesis in the immediate vicinity of the origin. We demonstrate that these replication-dependent mutational processes create the skew in base composition observed at human replication origins. Further, we show that mutagenesis associated with replication initiation exerts an influence on phenotypic diversity in human populations disproportionate to the origins genomic footprint: by increasing mutational loads at gene promoters and splice junctions the presence of an origin influences both gene expression and mRNA isoform usage. These findings have important implications for our understanding of the mutational processes that sculpt the human genome.

1994 ◽  
Vol 91 (8) ◽  
pp. 3166-3170 ◽  
Author(s):  
A. Di Rienzo ◽  
A. C. Peterson ◽  
J. C. Garza ◽  
A. M. Valdes ◽  
M. Slatkin ◽  
...  

2013 ◽  
Vol 42 (4) ◽  
pp. 2282-2294 ◽  
Author(s):  
Zhenfang Wu ◽  
Jingfang Liu ◽  
Haibo Yang ◽  
Hailong Liu ◽  
Hua Xiang

Abstract The use of multiple replication origins in archaea is not well understood. In particular, little is known about their specific control mechanisms. Here, we investigated the active replication origins in the three replicons of a halophilic archaeon, Haloarcula hispanica, by extensive gene deletion, DNA mutation and genome-wide marker frequency analyses. We revealed that individual origins are specifically dependent on their co-located cdc6 genes, and a single active origin/cdc6 pairing is essential and sufficient for each replicon. Notably, we demonstrated that the activities of oriC1 and oriC2, the two origins on the main chromosome, are differently controlled. A G-rich inverted repeat located in the internal region between the two inverted origin recognition boxes (ORBs) plays as an enhancer for oriC1, whereas the replication initiation at oriC2 is negatively regulated by an ORB-rich region located downstream of oriC2-cdc6E, likely via Cdc6E-titrating. The oriC2 placed on a plasmid is incompatible with the wild-type (but not the ΔoriC2) host strain, further indicating that strict control of the oriC2 activity is important for the cell. This is the first report revealing diverse control mechanisms of origins in haloarchaea, which has provided novel insights into the use and coordination of multiple replication origins in the domain of Archaea.


Viruses ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 324 ◽  
Author(s):  
Sumit Sharma ◽  
Marie Hagbom ◽  
Lennart Svensson ◽  
Johan Nordgren

Innate resistance to viral infections can be attributed to mutations in genes involved in the immune response, or to the receptor/ligand. A remarkable example of the latter is the recently described Mendelian trait resistance to clinically important and globally predominating genotypes of rotavirus, the most common agent of severe dehydrating gastroenteritis in children worldwide. This resistance appears to be rotavirus genotype-dependent and is mainly mediated by histo-blood group antigens (HBGAs), which function as a receptor or attachment factors on gut epithelial surfaces. HBGA synthesis is mediated by fucosyltransferases and glycosyltransferases under the genetic control of the FUT2 (secretor), FUT3 (Lewis), and ABO (H) genes on chromosome 19. Significant genotypic and phenotypic diversity of HBGA expression exists between different human populations. This genetic diversity has an effect on genotype-specific susceptibility, molecular epidemiology, and vaccine take. Here, we will discuss studies on genetic susceptibility to rotavirus infection and place them in the context of population susceptibility, rotavirus epidemiology, vaccine take, and public health impact.


1999 ◽  
Vol 19 (1) ◽  
pp. 547-555 ◽  
Author(s):  
Takayo Sasaki ◽  
Tomoyuki Sawado ◽  
Masamitsu Yamaguchi ◽  
Tomoyuki Shinomiya

ABSTRACT In the early stage of Drosophila embryogenesis, DNA replication initiates at unspecified sites in the chromosome. In contrast, DNA replication initiates in specified regions in cultured cells. We investigated when and where the initiation regions are specified during embryogenesis and compared them with those observed in cultured cells by two-dimensional gel methods. In the DNA polymerase α gene (DNApolα) locus, where an initiation region,oriDα, had been identified in cultured Kc cells, repression of origin activity in the coding region was detected after formation of cellular blastoderms, and the range of the initiation region had become confined by 5 h after fertilization. During this work we identified other initiation regions between oriDα and the Drosophila E2F gene (dE2F) downstream of DNApolα. At least four initiation regions showing replication bubbles were identified in the 65-kbDNApolα-dE2F locus in 5-h embryos, but only two were observed in Kc cells. These results suggest that the specification levels of origin usage in 5-h embryos are in the intermediate state compared to those in more differentiated cells. Further, we found a spatial correlation between the active promoter regions fordE2F and the active initiation zones of replication. In 5-h embryos, two known transcripts differing in their first exons were expressed, and two regions close to the respective promoter regions for both transcripts functioned as replication origins. In Kc cells, only one transcript was expressed and functional replication origins were observed only in the region including the promoter region for this transcript.


2006 ◽  
Vol 17 (1) ◽  
pp. 308-316 ◽  
Author(s):  
Prasanta K. Patel ◽  
Benoit Arcangioli ◽  
Stephen P. Baker ◽  
Aaron Bensimon ◽  
Nicholas Rhind

DNA replication initiates at discrete origins along eukaryotic chromosomes. However, in most organisms, origin firing is not efficient; a specific origin will fire in some but not all cell cycles. This observation raises the question of how individual origins are selected to fire and whether origin firing is globally coordinated to ensure an even distribution of replication initiation across the genome. We have addressed these questions by determining the location of firing origins on individual fission yeast DNA molecules using DNA combing. We show that the firing of replication origins is stochastic, leading to a random distribution of replication initiation. Furthermore, origin firing is independent between cell cycles; there is no epigenetic mechanism causing an origin that fires in one cell cycle to preferentially fire in the next. Thus, the fission yeast strategy for the initiation of replication is different from models of eukaryotic replication that propose coordinated origin firing.


2017 ◽  
Vol 45 (13) ◽  
pp. 7807-7824 ◽  
Author(s):  
Koichi Utani ◽  
Haiqing Fu ◽  
Sang-Min Jang ◽  
Anna B. Marks ◽  
Owen K. Smith ◽  
...  

2018 ◽  
Vol 3 ◽  
pp. 23 ◽  
Author(s):  
Ana B.A. Wallis ◽  
Conrad A. Nieduszynski

Background: Understanding DNA replication initiation is essential to understand the mis-regulation of replication seen in cancer and other human disorders. DNA replication initiates from DNA replication origins. In eukaryotes, replication is dependent on cell cycle kinases which function during S phase. Dbf4-dependent kinase (DDK) and cyclin-dependent kinase (CDK) act to phosphorylate the DNA helicase (composed of mini chromosome maintenance proteins: Mcm2-7) and firing factors to activate replication origins. It has recently been found that Rif1 can oppose DDK phosphorylation. Rif1 can recruit protein phosphatase 1 (PP1) to dephosphorylate MCM and restricts origin firing. In this study, we investigate a potential role for another phosphatase, protein phosphatase 2A (PP2A), in regulating DNA replication initiation. The PP2A regulatory subunit Rts1 was previously identified in a large-scale genomic screen to have a genetic interaction with ORC2 (a DNA replication licensing factor). Deletion of RTS1 synthetically rescued the temperature-sensitive (ts-) phenotype of ORC2 mutants. Methods: We deleted RTS1 in multiple ts-replication factor Saccharomyces cerevisiae strains, including ORC2.  Dilution series assays were carried out to compare qualitatively the growth of double mutant ∆rts1 ts-replication factor strains relative to the respective single mutant strains.   Results: No synthetic rescue of temperature-sensitivity was observed. Instead we found an additive phenotype, indicating gene products function in separate biological processes. These findings are in agreement with a recent genomic screen which found that RTS1 deletion in several ts-replication factor strains led to increased temperature-sensitivity. Conclusions: We find no evidence that Rts1 is involved in the dephosphorylation of DNA replication initiation factors.


2017 ◽  
Author(s):  
Artem V. Artemov ◽  
Maria A. Andrianova ◽  
Georgii A. Bazykin ◽  
Vladimir B. Seplyarskiy

AbstractError-prone mutants of polymerase epsilon (POLE*) or polymerase delta (POLD1*) induce a mutator phenotype in human cancers. Here we show that the rate of mutations introduced by POLD1* is elevated by 50%, while the rate of POLE*-induced mutations is decreased twofold, within one kilobase from replication origins. These results support a model in which POLD1 replicates both the leading and the lagging strands within a kilobase from an origin. The magnitude of the mutational bias suggests that the probability of an individual origin to initiate replication exceeds 50%, which is much higher than previous estimates. Using additional data from nascent DNA sequencing and Okazaki fragments sequencing (OK-seq) experiments, we showed that a majority of origins are firing at each replication round, but the initiated replication fork does not propagate further than 1Kb in both directions. Analyses based on mutational data and on OK-seq data concordantly suggest that only approximately a quarter of fired origins result in a processive replication fork. Taken together, our results provide a new model of replication initiation.


1998 ◽  
Vol 64 (8) ◽  
pp. 2822-2830 ◽  
Author(s):  
Patricia A. Sobecky ◽  
Tracy J. Mincer ◽  
Michelle C. Chang ◽  
Aresa Toukdarian ◽  
Donald R. Helinski

ABSTRACT Naturally occurring plasmids isolated from heterotrophic bacterial isolates originating from coastal California marine sediments were characterized by analyzing their incompatibility and replication properties. Previously, we reported on the lack of DNA homology between plasmids from the culturable bacterial population of marine sediments and the replicon probes specific for a number of well-characterized incompatibility and replication groups (P. A. Sobecky, T. J. Mincer, M. C. Chang, and D. R. Helinski, Appl. Environ. Microbiol. 63:888–895, 1997). In the present study we isolated 1.8- to 2.3-kb fragments that contain functional replication origins from one relatively large (30-kb) and three small (<10-kb) naturally occurring plasmids present in different marine isolates. 16S rRNA sequence analyses indicated that the four plasmid-bearing marine isolates belonged to the α and γ subclasses of the classProteobacteria. Three of the marine sediment isolates are related to the γ-3 subclass organisms Vibrio splendidusand Vibrio fischeri, while the fourth isolate may be related to Roseobacter litoralis. Sequence analysis of the plasmid replication regions revealed the presence of features common to replication origins of well-characterized plasmids from clinical bacterial isolates, suggesting that there may be similar mechanisms for plasmid replication initiation in the indigenous plasmids of gram-negative marine sediment bacteria. In addition to replication inEscherichia coli DH5α and C2110, the host ranges of the plasmid replicons, designated repSD41, repSD121, repSD164, and repSD172, extended to marine species belonging to the generaAchromobacter, Pseudomonas,Serratia, and Vibrio. While sequence analysis of repSD41 and repSD121 revealed considerable stretches of homology between the two fragments, these regions do not display incompatibility properties against each other. The replication origin repSD41 was detected in 5% of the culturable plasmid-bearing marine sediment bacterial isolates, whereas the replication origins repSD164 and repSD172 were not detected in any plasmid-bearing bacteria other than the parental isolates. Microbial community DNA extracted from samples collected in November 1995 and June 1997 and amplified by PCR yielded positive signals when they were hybridized with probes specific for repSD41 and repSD172 replication sequences. In contrast, replication sequences specific for repSD164 were not detected in the DNA extracted from marine sediment microbial communities.


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