Mclainchristiansen4749

© 2020, Kan et al.Deinococcus radiodurans (DR) survives in the presence of hundreds of double-stranded DNA (dsDNA) breaks by efficiently repairing such breaks. RecO, an essential protein for the extreme radioresistance of DR, is one of the major recombination mediator proteins in the RecA-loading process in the RecFOR pathway. find more However, how RecO participates in the RecA-loading process is still unclear. In this work, we investigated the function of drRecO using single-molecule techniques. We found that drRecO competes with the ssDNA binding protein (drSSB) for binding to the freely exposed ssDNA and efficiently displaces drSSB from ssDNA without consuming ATP. drRecO replaces drSSB and dissociates it completely from ssDNA even though drSSB binds to ssDNA approximately 300 times more strongly than drRecO does. We suggest that drRecO facilitates the loading of RecA onto drSSB-coated ssDNA by utilizing a small drSSB-free space on ssDNA generated by the fast diffusion of drSSB on ssDNA.Thylakoid membranes scaffold an assortment of large protein complexes that work together to harness the energy of light. It has been a longstanding challenge to visualize how the intricate thylakoid network organizes these protein complexes to finely tune the photosynthetic reactions. Previously, we used in situ cryo-electron tomography to reveal the native architecture of thylakoid membranes (Engel et al., 2015). Here, we leverage technical advances to resolve the individual protein complexes within these membranes. Combined with a new method to visualize membrane surface topology, we map the molecular landscapes of thylakoid membranes inside green algae cells. Our tomograms provide insights into the molecular forces that drive thylakoid stacking and reveal that photosystems I and II are strictly segregated at the borders between appressed and non-appressed membrane domains. This new approach to charting thylakoid topology lays the foundation for dissecting photosynthetic regulation at the level of single protein complexes within the cell. © 2020, Wietrzynski et al.Notch pathway haploinsufficiency can cause severe developmental syndromes with highly variable penetrance. Currently, we have a limited mechanistic understanding of phenotype variability due to gene dosage. Here, we unexpectedly found that inserting an enhancer containing pioneer transcription factor sites coupled to Notch dimer sites can induce a subset of Notch haploinsufficiency phenotypes in Drosophila with wild type Notch gene dose. Using Drosophila genetics, we show that this enhancer induces Notch phenotypes in a Cdk8-dependent, transcription-independent manner. We further combined mathematical modeling with quantitative trait and expression analysis to build a model that describes how changes in Notch signal production versus degradation differentially impact cellular outcomes that require long versus short signal duration. Altogether, these findings support a 'bind and discard' mechanism in which enhancers with specific binding sites promote rapid Cdk8-dependent Notch turnover, and thereby reduce Notch-dependent transcription at other loci and sensitize tissues to gene dose based upon signal duration. © 2020, Kuang et al.The precise relationship between epigenetic perturbations and telomere dysfunction is an extant question. Previously, we showed that telomere dysfunction leads to differentiation instability in murine embryonic stem cells (mESCs) via perturbations in DNA methylation at pluripotency-factor promoters. Here, we uncovered that telomerase reverse transcriptase null (Tert-/-) mESCs exhibit genome-wide perturbations in chromatin accessibility and gene expression during differentiation. These changes were accompanied by an increase of H3K27me3 globally, an altered chromatin landscape at the Pou5f1/Oct4 pluripotency gene promoter, and impaired Tert-/- mESC differentiation. Inhibition of the Polycomb Repressive Complex 2 (PRC2), an H3K27 tri-methyltransferase, exacerbated the impairment in differentiation and pluripotency gene repression in Tert-/- mESCs but not wild-type mESCs, whereas inhibition of H3K27me3 demethylation led to a partial rescue of the Tert-/- phenotype. This data reveals a new interdependent relationship between H3K27me3 and telomere integrity in stem cell lineage commitment that may have implications in aging and cancer. link2 © 2020, Criqui et al.Post-translationally modified peptides are involved in many aspects of plant growth and development. The maturation of these peptides from their larger precursors is still poorly understood. We show here that the biogenesis of CLEL6 and CLEL9 peptides in Arabidopsis thaliana requires a series of processing events in consecutive compartments of the secretory pathway. Following cleavage of the signal peptide upon entry into the endoplasmic reticulum (ER), the peptide precursors are processed in the cis-Golgi by the subtilase SBT6.1. SBT6.1-mediated cleavage within the variable domain allows for continued passage of the partially processed precursors through the secretory pathway, and for subsequent post-translational modifications including tyrosine sulfation and proline hydroxylation within, and proteolytic maturation after exit from the Golgi. Activation by subtilases including SBT3.8 in post-Golgi compartments depends on the N-terminal aspartate of the mature peptides. Our work highlights the complexity of post-translational precursor maturation allowing for stringent control of peptide biogenesis. © 2020, Stührwohldt et al.The mitotic deacetylase complex (MiDAC) is a recently identified histone deacetylase (HDAC) complex. While other HDAC complexes have been implicated in neurogenesis, the physiological role of MiDAC remains unknown. Here, we show that MiDAC constitutes an important regulator of neural differentiation. We demonstrate that MiDAC functions as a modulator of a neurodevelopmental gene expression program and binds to important regulators of neurite outgrowth. MiDAC upregulates gene expression of pro-neural genes such as those encoding the secreted ligands SLIT3 and NETRIN1 (NTN1) by a mechanism suggestive of H4K20ac removal on promoters and enhancers. Conversely, MiDAC inhibits gene expression by reducing H3K27ac on promoter-proximal and -distal elements of negative regulators of neurogenesis. Furthermore, loss of MiDAC results in neurite outgrowth defects that can be rescued by supplementation with SLIT3 and/or NTN1. These findings indicate a crucial role for MiDAC in regulating the ligands of the SLIT3 and NTN1 signaling axes to ensure the proper integrity of neurite development. © 2020, Mondal et al.The use of non-viral vectors for in vivo gene therapy could drastically increase safety, whilst reducing the cost of preparing the vectors. A promising approach to non-viral vectors makes use of DNA/cationic liposome complexes (lipoplexes) to deliver the genetic material. Here we use coarse-grained molecular dynamics simulations to investigate the molecular mechanism underlying efficient DNA transfer from lipoplexes. Our computational fusion experiments of lipoplexes with endosomal membrane models show two distinct modes of transfection parallel and perpendicular. In the parallel fusion pathway, DNA aligns with the membrane surface, showing very quick release of genetic material shortly after the initial fusion pore is formed. link3 The perpendicular pathway also leads to transfection, but release is slower. We further show that the composition and size of the lipoplex, as well as the lipid composition of the endosomal membrane, have a significant impact on fusion efficiency in our models. © 2020, Bruininks et al.Among all 209 discharged coronavirus 2019 patients in Shenzhen China between January 23 and February 21, 2020, there are 9 (4.3%) patients showed RT-PCR positive in throat swabs, 13 (6.2%) patients showed RT-PCR positive in anal swabs, and 22 (10.5%) positive in either type. The time between discharge and positive RT-PCR tests is 4.7 days on average. These numbers shed light on the viral dynamics of COVID-19.Objective To conduct a scoping review of measure utilization in Latin America. We relate the findings to the needs of the region and give recommendations for measure usage in LA.Methods Six electronic databases (PubMed, Web of Science, CINAHL, PsychInfo, SCOPUS, and SCIELO) were searched to identify peer-reviewed literature. In total, 207 studies using change and/or outcome measures were identified based on a priori inclusion criteria.Results Production by country varied markedly; more than three quarters of the studies took place in just three of the 20 Latin American countries Brazil, Chile, and Mexico. The most frequently used measures were the Outcome Questionnaire, Beck Depression Inventory-II, Hamilton Rating Scale, and Yale-Brown Obsessive-Compulsive Scale. The most common diagnosis was depression (n = 54).Conclusions Outcome and change research in Latin America is growing rapidly but future efforts should focus more tightly on the needs of the region, as well as on forging collaborations with researchers from other regions. The use of change measures for serial assessment throughout interventions is recommended in view of its adaptability to highly diverse Latin American social realities. Dissemination of research findings and promotion of outcome and change measure use through implementation of public policy is recommended.Trust is a key determinant of whether people rely on automated systems in the military and the public. However, there is currently no standard for measuring trust in automated systems. In the present studies, we propose a scale to measure trust in automated systems that is grounded in current research and theory on trust formation, which we refer to as the Trust in Automated Systems Test (TOAST). We evaluated both the reliability of the scale structure and criterion validity using independent, military-affiliated and civilian samples. In both studies we found that the TOAST exhibited a two-factor structure, measuring system understanding and performance (respectively), and that factor scores significantly predicted scores on theoretically related constructs demonstrating clear criterion validity. We discuss the implications of our findings for advancing the empirical literature and in improving interface design.The present global health emergency involving the emergence and rapid spread of a novel coronavirus has prompted the world scientific community to consider how it can help to fight this growing viral pandemic. With few safe and effective drugs available to combat this threat to humanity and the normal functioning of our society, the oligonucleotide research community is uniquely positioned to apply its technology and expertise to help alleviate the crisis, thanks to its capacity for rational drug design, swift development cycles, and pursuing targets undruggable by conventional treatment strategies.Background Home health care nurses (HHNs) work alone in patients' homes. They experience high rates of Type II (client/patient-on-worker) workplace violence (WPV); however, little is known about the extent and factors of their reporting. Methods A convenience sample of employees aged 18 years and older and working as an HHN or management staff were recruited from a U.S. nonprofit home health care agency. To describe the extent of reporting of WPV events, an HHN survey was conducted. To identify the barriers and facilitators to reporting, two HHN focus groups were conducted, and management key informant interviews were employed. Findings We recruited 18 HHNs and five management staff into the study. Almost all HHNs reported to management the most serious forms of violence they experienced, and that HHNs reported WPV when they perceived that reporting was beneficial (alerting other nurses and management) and supported by management staff. However, they were unwilling to report when it was perceived as disadvantageous (reliving the trauma), discouraged (by a norm that experiencing violence is a part of the job), unachievable (unstandardized reporting process), and ambiguous (uncertain of what is reportable).