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DNA replication generates torsional stress. Here, the authors found the T7 replisome to be a powerful rotary motor. Helicase-DNA polymerase interactions stabilize stalled forks, enabling restart after gyrase torsional relaxation, highlighting torsion as a key regulator of replication.

The neural dynamics of emotional memory consolidation are not well understood. Here, the authors analyse intracranial recordings from human participants after emotional memory encoding, showing that ripple-locked activity in the amygdala and hippocampus is predictive of subsequent memory.

Reactive arthritis is a form of inflammatory arthritis associated with bacterial infection. In this article, the authors describe the current state of our knowledge regardingChlamydia-induced reactive arthritis, including chlamydial persistence in joints, susceptibility factors and host and pathogen biology, and discuss future research priorities in this disease.

SCAI is novel protein that inhibits the transcription factor MAL and represses the expression of β₁-integrin. Reduced SCAI levels also correlate with increased invasive cell migration.

Here the authors discover that chromatin stimulates topoisomerase II function by enabling the enzyme to achieve exceptionally high processivity and efficient supercoiling relaxation, even under low torsional stress.

The authors present the case of a 49-year-old man diagnosed with chronic unilateral sacroiliitis who did not respond to conventional therapy with corticosteroids and NSAIDs. A single intra-articular injection of the tumor necrosis factor inhibitor infliximab resulted in gradual and steady improvements in pain, stiffness and inflammation.

Although bacterial infections are implicated in the pathogenesis of reactive arthritis, the role of pathogens in the development of other spondyloarthropathies is unresolved. In this Review, the natural history of infection-triggered arthritis, the mechanisms of disease development, and the potential for antibiotic therapy to modify the course of the disease are discussed.

An array of optical traps formed in a nanophotonic waveguide can trap and manipulate biomolecular nanoparticles in three dimensions.

Kiourtis et al. show that liver senescence triggers senescence and dysfunction in other organs through TGFβ secretion from the liver.

Matthew Brown, Peter Donnelly and colleagues report results of a genome-wide association meta-analysis and follow-up study of ankylosing spondylitis. They identify three new risk variants and report a genetic interaction between ERAP1 and HLA-B27, implicating aberrant peptide handling in the pathophysiology of this disease.

Replicating the genome presents a major challenge to the maintenance of the epigenetic landscape. Here the authors use a minimal experimental system to show how nucleosomes are transferred to double-stranded DNA, with the transfer mediated by a quantitative loop formation model.

The next step after sequencing a genome is to figure out how the cell actually uses it as an instruction manual. A large international consortium has examined 1% of the genome for what part is transcribed, where proteins are bound, what the chromatin structure looks like, and how the sequence compares to that of other organisms.

Several studies have shown that the gene encoding endoplasmic reticulum aminopeptidase 1 (ERAP1) is associated with ankylosing spondylitis (AS). ERAP1 and the closely related ERAP2 are involved in trimming peptides within the endoplasmic reticulum for loading onto major histocompatibility complex molecules; ERAP1 also has a role in releasing some membrane-bound cytokine receptors. The potential contributions of these aminopeptidases to the pathogenesis of AS are outlined in this Review.

We show that the human hippocampus exhibits two distinct theta oscillations during spatial navigation with the faster oscillation in posterior regions showing movement modulation. This result suggests a distinct feature of the human hippocampus compared to rodents, which generally show a single 8 Hz rhythm.

Transfer of senescent cells into naive, young mice can induce physical dysfunction, and a senolytic can reverse this dysfunction and potently increase lifespan in aged mice.

Qasim et al. describe neurons in the human entorhinal cortex that activate near the locations in space that a person is cued to recall during a memory task. These results show one way in which the cognitive map shifts according to memory demands.

Ankylosing spondylitis is a common, highly inheritable inflammatory arthritis with poorly understood biology. Here Brown, Cortes and colleagues use fine mapping of the major histocompatibility complex and identify novel associations, and identify other HLA alleles that like HLA-B27 interact with ERAP1 variants to influence disease risk.

Hall et al. discovered the molecular mechanism for the polarity of the CRISPR roadblock to transcription: RNA polymerase progression can collapse the R-loop formed by a bound dCas to allow read-through from the PAM-distal side. Guide RNA modifications allow modulation of the dCas R-loop stability.

During DNA replication, replicative helicases play an essential role for DNA unwinding to occur. Here the authors find that bacteriophage T7 helicase is also involved in replication re-initiation by interacting with a non-replicating DNAP and increasing unwinding rate.

Genomic instability can result from stalled or collapsed replication fork at sites of unrepaired DNA lesions. Here the authors uncover a new lesion bypass pathway for the T7 replisome, where leading strand template lesions can be overcome through interaction between the replisome's helicase and polymerase components.

Memory lapses can occur due to ineffective encoding, but it is unclear if targeted brain stimulation can improve memory performance. Here, authors use a closed-loop system to decode and stimulate periods of ineffective encoding, showing that stimulation of lateral temporal cortex can enhance memory.

Cybulsky and colleagues show that myeloid cells in the arterial intima undergo reverse transendothelial migration into the arterial circulation that is dependent on the chemokine CCL19 and its receptor CCR7.

In this Review, the authors summarize the different types of pain experienced by patients with ankylosing spondylitis, the underlying neurobiology and studies that are providing insights into the complex interplay between the immune system and neural pain-processing pathways.

Multiplexed detection of luciferase-based sensors in the same sample is challenging and limited by the substrates’ emission spectra. Here the authors establish a system based on three different luciferases and sequential detection to achieve measurements of up to six parameters within the same experiment.

The mechanisms underlying the genetic association between HLA-B27 and ankylosing spondylitis, including the contribution of endoplasmic reticulum aminopeptidase 1 (ERAP1), continue to elude the field. New findings support the involvement of the unfolded protein response and highlight the therapeutic potential and limitations of targeting ERAP1 in this disease.

Results from an experimental manipulation showed a significant survival advantage for rare genotypes in natural populations of guppies, confirming that frequency-dependent selection can act as a potent mechanism in maintaining genetic variation in natural populations.