Inter-subunit interactions that coordinate Rad51's activities

Rad51 is the central catalyst of homologous recombination in eukaryotes and is thus critical for maintaining genomic integrity. Recent crystal structures of filaments formed by Rad51 and the closely related archeal RadA and eubacterial RecA proteins place the ATPase site at the protomeric interface. To test the relevance of this feature, we mutated conserved residues at this interface and examined their effects on key activities of Rad51: ssDNA-stimulated ATP hydrolysis, DNA binding, polymerization on DNA substrates and catalysis of strand-exchange reactions. Our results show that the interface seen in the crystal structures is very important for nucleoprotein filament formation. H352 and R357 of yeast Rad51 are essential for assembling the catalytically competent form of the enzyme on DNA substrates and coordinating its activities. However, contrary to some previous suggestions, neither of these residues is critical for ATP hydrolysis

A tabletop x-ray tomography instrument for nanometer-scale imaging: demonstration of the 1,000-element transition-edge sensor subarray

We report on the 1,000-element transition-edge sensor (TES) x-ray spectrometer implementation of the TOMographic Circuit Analysis Tool (TOMCAT). TOMCAT combines a high spatial resolution scanning electron microscope (SEM) with a highly efficient and pixelated TES spectrometer to reconstruct three-dimensional maps of nanoscale integrated circuits (ICs). A 240-pixel prototype spectrometer was recently used to reconstruct ICs at the 130 nm technology node, but to increase imaging speed to more practical levels, the detector efficiency needs to be improved. For this reason, we are building a spectrometer that will eventually contain 3,000 TES microcalorimeters read out with microwave superconducting quantum interference device (SQUID) multiplexing, and we currently have commissioned a 1,000 TES subarray. This still represents a significant improvement from the 240-pixel system and allows us to begin characterizing the full spectrometer performance. Of the 992 maximimum available readout channels, we have yielded 818 devices, representing the largest number of TES x-ray microcalorimeters simultaneously read out to date. These microcalorimeters have been optimized for pulse speed rather than purely energy resolution, and we measure a FWHM energy resolution of 14 eV at the 8.0 keV Cu K$\alpha$ line.Comment: 5 pages, 4 figures, submitted to IEEE Transactions on Applied Superconductivit

Elderly with Autism: Executive Functions and Memory

Cognitive autism research is mainly focusing on children and young adults even though we know that autism is a life-long disorder and that healthy aging already has a strong impact on cognitive functioning. We compared the neuropsychological profile of 23 individuals with autism and 23 healthy controls (age range 51–83 years). Deficits were observed in attention, working memory, and fluency. Aging had a smaller impact on fluency in the high functioning autism (HFA) group than in the control group, while aging had a more profound effect on visual memory performance in the HFA group. Hence, we provide novel evidence that elderly with HFA have subtle neuropsychological deficits and that the developmental trajectories differ between elderly with and without HFA in particular cognitive domains

doi:10.1093/nar/gkn973 Inter-subunit interactions that coordinate Rad51’s activities

Rad51 is the central catalyst of homologous recombination in eukaryotes and is thus critical for maintaining genomic integrity. Recent crystal structures of filaments formed by Rad51 and the closely related archeal RadA and eubacterial RecA proteins place the ATPase site at the protomeric interface. To test the relevance of this feature, we mutated conserved residues at this interface and examined their effects on key activities of Rad51: ssDNA-stimulated ATP hydrolysis, DNA binding, polymerization on DNA substrates and catalysis of strand-exchange reactions. Our results show that the interface seen in the crystal structures is very important for nucleoprotein filament formation. H352 and R357 of yeast Rad51 are essential for assembling the catalytically competent form of the enzyme on DNA substrates and coordinating its activities. However, contrary to some previous suggestions, neither of these residues is critical for ATP hydrolysis

Human USP3 is a chromatin modifier required for S phase progression and genome stability

SummaryProtein ubiquitination is critical for numerous cellular functions, including DNA damage response pathways [1, 2]. Histones are the most abundant monoubiquitin conjugates in mammalian cells; however, the regulation and the function of monoubiquitinated H2A (uH2A) and H2B (uH2B) remain poorly understood. In particular, little is known about mammalian deubiquitinating enzymes (DUBs) that catalyze the removal of ubiquitin from uH2A/uH2B. Here we identify the ubiquitin-specific protease 3 USP3 as a deubiquitinating enzyme for uH2A and uH2B. USP3 dynamically associates with chromatin and deubiquitinates H2A/H2B in vivo. The ZnF-UBP domain of USP3 mediates uH2A-USP3 interaction. Functional ablation of USP3 by RNAi leads to delay of S phase progression and to accumulation of DNA breaks, with ensuing activation of DNA damage checkpoint pathways. In addition, we show that in response to ionizing radiation, (1) uH2A redistributes and colocalizes in γ-H2AX DNA repair foci and (2) USP3 is required for full deubiquitination of ubiquitin-conjugates/uH2A and γ-H2AX dephosphorylation. Our studies identify USP3 as a novel regulator of H2A and H2B ubiquitination, highlight its role in preventing replication stress, and suggest its involvement in the response to DNA double-strand breaks. Together, our results implicate USP3 as a novel chromatin modifier in the maintenance of genome integrity

Effect of an intensive 3-day social cognitive treatment (can do treatment) on control self-efficacy in patients with relapsing remitting multiple sclerosis and low disability:A single-centre randomized controlled trial

In patients with chronic disorders, control self-efficacy is the confidence with managing symptoms and coping with the demands of illness. Can do treatment (CDT) is an intensive, 3-day, social cognitive theory-based, multidisciplinary treatment that focuses on identification of stressors, goal setting, exploration of boundaries, and establishment of new boundaries. An uncontrolled study showed that patients with relapsing remitting multiple sclerosis (RRMS) and low-disability had improved control self-efficacy six months after CDT. Hence, in a 6-month, single-centre, randomized (1:1), unmasked, controlled trial in RRMS patients with Expanded Disability Status Scale (EDSS) scor

An intensive social cognitive program (can do treatment) in people with relapsing remitting multiple sclerosis and low disability: a randomized controlled trial protocol

BACKGROUND: In people with multiple sclerosis (MS) disabilities and limitations may negatively affect self-efficacy. Lowered self-efficacy has been associated with decreases in health-related quality of life, physical activity and cognitive performance. In an explorative observational study we found that a 3-day intensive social cognitive program (Can Do Treatment [CDT]) with the participation of support partners was followed by substantial increases in self-efficacy control and health-related quality of life 6 months after treatment in those people with MS who had relapsing remitting disease and low disability. METHODS/DESIGN: CDT is a sociologically oriented approach, its goal is to uncover and promote existing capabilities, and the notion “stressor” is the central concept. CDT’s components are plenary group sessions, small group sessions, consultations, a theatre evening, and start of the day with a joint activity. The small group sessions form the actual training. Depending on their individual goals the participants join the training groups ‘Body’, ‘Feeling’ or ‘Life’, to work out their aims and to reduce their stressors. The multidisciplinary team includes a psychiatrist, psychiatric nurse, neurologist, specialized MS nurse, physiotherapist, dance therapist, and a person with MS. To evaluate the (cost)effectiveness of CDT in persons with relapsing remitting MS and low disability we perform a single-centre, randomized controlled trial in 140 patients, with or without support partners. The primary outcome is self-efficacy control. The secondary outcomes are self-efficacy function, health-related quality of life, autonomy and participation, anxiety, depression, cost effectiveness and cost utility. The tertiary outcome is care-related strain to support partners. Outcomes are assessed at baseline and at 1, 3 and 6 months after CDT. DISCUSSION: This randomized controlled trial will adequately evaluate the clinical and cost effectiveness of a 3-day intensive social cognitive program in people with relapsing remitting MS and low disability, with self-efficacy control as primary outcome. DUTCH TRIAL REGISTRY: Application number: 2244

Clinical Impact of Comprehensive Molecular Profiling in Adolescents and Young Adults with Sarcoma

Sarcomas are a heterogenous group of tumours that commonly carry poor prognosis with limited therapeutic options. Adolescents and young adults (AYAs) with sarcoma are a unique and understudied patient population that have only achieved modest survival gains compared to other groups. We present our institutional experience of AYAs with sarcoma who underwent comprehensive molecular profiling (CMP) via either large-panel targeted DNA sequencing or whole genome and transcriptome sequencing and evaluated the feasibility and clinical impact of this approach. Genomic variants detected were determined to be clinically relevant and actionable following evaluation by the Molecular Tumour Board. Clinicians provided feedback regarding the utility of testing three months after reporting. Twenty-five patients who were recruited for CMP are included in this analysis. The median time from consent to final molecular report was 45 days (interquartile range: 37–57). Potentially actionable variants were detected for 14 patients (56%), and new treatment recommendations were identified for 12 patients (48%). Pathogenic germline variants were identified in three patients (12%), and one patient had a change in diagnosis. The implementation of CMP for AYAs with sarcoma is clinically valuable, feasible, and should be increasingly integrated into routine clinical practice as technologies and turnaround times continue to improve