Project description:Chromosome duplication normally initiates via the assembly of replication fork complexes at defined origins. DNA synthesis by any one fork is thought to cease when it meets another travelling in the opposite direction, at which stage the replication machinery may simply dissociate before the nascent strands are finally ligated. But what actually happens is not clear. Here we present evidence consistent with the idea that every fork collision has the potential to trigger re-replication of the already replicated DNA, thus posing a threat to genomic integrity. In Escherichia coli this threat is kept at bay by the RecG DNA translocase. Without RecG, replication initiates where forks meet, establishing new forks with the potential to sustain cell growth and division in the absence of an active origin. The studies reported raise the question of how eukaryotic and archaeal cells are able to exploit multiple origins for the duplication of each chromosome without any apparent ill effect from the consequent multiple fork collisions.

2013-07-22 | GSE41975 | GEO

Broad and specific anti-defense genes in bacteriophage genomes

Project description:Bacteria and bacteriophages have been engaged in a relentless evolutionary arms race, driving a rapid evolution of bacterial defense mechanisms and leading to their scattered distribution across genomes. We hypothesized that the variability in defense systems presence in bacterial genomes leads to equally variable counter-defense repertoires in phage genomes. To test this, we analyzed the variable regions in Pseudomonas model phages of the Pbunavirus genus, uncovering five anti-defense genes inhibiting Zorya type I, RADAR, Hypnos, Druantia type I and III, and Thoeris type III. Remarkably, a typical Pbunavirus encodes up to five known anti-defense genes, some inhibiting four unrelated defense systems with distinct nucleic acid-targeting mechanisms. Structural searches revealed that these broad-acting inhibitors are encoded across diverse phage taxa infecting multiple bacterial hosts. The presence of both broad and specific inhibitors suggests that defense systems exert a strong selective pressure, and their utility presents opportunities to improve phage-based therapeutics.

2026-02-23 | PXD063439 | Pride

Double trouble? When a pandemic and seasonal virus collide.

Project description: Not available

| S-EPMC7276009 | biostudies-literature

When worlds collide: IP(3) receptors and the ERAD pathway.

Project description: Not available

| S-EPMC2752845 | biostudies-literature

Bacterial Genes Outnumber Archaeal Genes in Eukaryotic Genomes.

Project description: Not available

| S-EPMC7151554 | biostudies-literature

When positive outcomes and reality collide: Children prefer optimists as social partners.

Project description: Not available