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About 106,663 results

Structural basis for intrinsic transcription termination.
https://doi.org/10.1038/s41586-022-05604-1
Nature You L, Omollo EO et. al.

Jan 12th, 2023 - Efficient and accurate termination is required for gene transcription in all living organisms1,2. Cellular RNA polymerases in both bacteria and eukaryotes can terminate their transcription through a factor-independent termination pathway3,4-called intrinsic termination transcription in bacteria-in which RNA polymerase recognizes terminator sequences, stops nucleotide addition and releases nasce...

Structures and mechanisms of tRNA methylation by METTL1-WDR4.
https://doi.org/10.1038/s41586-022-05565-5
Nature Ruiz-Arroyo VM, Raj R et. al.

Jan 5th, 2023 - Specific, regulated modification of RNAs is important for proper gene expression1,2. tRNAs are rich with various chemical modifications that affect their stability and function3,4. 7-Methylguanosine (m7G) at tRNA position 46 is a conserved modification that modulates steady-state tRNA levels to affect cell growth5,6. The METTL1-WDR4 complex generates m7G46 in humans, and dysregulation of METTL1...

Characterization of white matter microstructural abnormalities associated with cognitiv...
https://doi.org/10.1016/j.jad.2022.12.070
Journal of Affective Disorders; Sui C, Wen H et. al.

Dec 31st, 2022 - Diffusion tensor imaging (DTI) is recommended as a sensitive method to explore white matter (WM) microstructural alterations. Cerebral small vessel disease (CSVD) may be accompanied by extensive WM microstructural deterioration, while cerebral microbleeds (CMBs) are an important factor affecting CSVD. Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivi...

Confocal Laser and Electron Microscopic Investigation of Gap Junctions in Anaplastic As...
https://doi.org/10.1007/978-3-031-14190-4_50
Advances in Experimental Medicine and Biology; Logvinov AK, Kirichenko EY et. al.

Dec 18th, 2022 - Connexin 43 (Cx43) is a multifunction protein that forms gap junction channels and hemichannels and is suggested to play an essential role in oxygen-glucose deprivation, induced via neuroinflammation during astrocytoma expansion into healthy tissue. To prove this assumption we studied connexin 43 localisation and ultrastructure of gap junctions in samples of malignant brain tumour (anaplastic a...

Structural insights into the mechanism of the sodium/iodide symporter.
https://doi.org/10.1038/s41586-022-05530-2
Nature Ravera S, Nicola JP et. al.

Dec 15th, 2022 - The sodium/iodide symporter (NIS) is the essential plasma membrane protein that mediates active iodide (I-) transport into the thyroid gland, the first step in the biosynthesis of the thyroid hormones-the master regulators of intermediary metabolism. NIS couples the inward translocation of I- against its electrochemical gradient to the inward transport of Na+ down its electrochemical gradient1,...

Microbial predators form a new supergroup of eukaryotes.
https://doi.org/10.1038/s41586-022-05511-5
Nature Tikhonenkov DV, Mikhailov KV et. al.

Dec 9th, 2022 - Molecular phylogenetics of microbial eukaryotes has reshaped the tree of life by establishing broad taxonomic divisions, termed supergroups, that supersede the traditional kingdoms of animals, fungi and plants, and encompass a much greater breadth of eukaryotic diversity1. The vast majority of newly discovered species fall into a small number of known supergroups. Recently, however, a handful o...

Arachnoid granulations are lymphatic conduits that communicate with bone marrow and dur...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9728136
The Journal of Experimental Medicine; Shah T, Leurgans SE et. al.

Dec 6th, 2022 - Arachnoid granulations (AG) are poorly investigated. Historical reports suggest that they regulate brain volume by passively transporting cerebrospinal fluid (CSF) into dural venous sinuses. Here, we studied the microstructure of cerebral AG in humans with the aim of understanding their roles in physiology. We discovered marked variations in AG size, lobation, location, content, and degree of s...

Cross-Species Permissivity: Structure of a Goat Adeno-Associated Virus and Its Complex ...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9769368
Journal of Virology; Large EE, Silveria MA et. al.

Dec 2nd, 2022 - Adeno-associated virus (AAV) is a small ssDNA satellite virus of high interest (in recombinant form) as a safe and effective gene therapy vector. AAV's human cell entry receptor (AAVR) contains polycystic kidney disease (PKD) domains bound by AAV. Seeking understanding of the spectrum of interactions, goat AAVGo.1 is investigated, because its host is the species most distant from human with rec...

Structural Studies Reveal that Endosomal Cations Promote Formation of Infectious Coxsac...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9769374
Journal of Virology; Domanska A, Plavec Z et. al.

Dec 1st, 2022 - Coxsackievirus A9 (CVA9), an enterovirus, is a common cause of pediatric aseptic meningitis and neonatal sepsis. During cell entry, enterovirus capsids undergo conformational changes leading to expansion, formation of large pores, externalization of VP1 N termini, and loss of the lipid factor from VP1. Factors such as receptor binding, heat, and acidic pH can trigger capsid expansion in some en...

Structure-based design of bitopic ligands for the µ-opioid receptor.
https://doi.org/10.1038/s41586-022-05588-y
Nature Faouzi A, Wang H et. al.

Dec 1st, 2022 - Mu-opioid receptor (µOR) agonists such as fentanyl have long been used for pain management, but are considered a major public health concern owing to their adverse side effects, including lethal overdose1. Here, in an effort to design safer therapeutic agents, we report an approach targeting a conserved sodium ion-binding site2 found in µOR3 and many other class A G-protein-coupled receptors wi...

Ninj2 regulates Schwann cells development by interfering laminin-integrin signaling.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9691370
Theranostics Sun Y, Chen X et. al.

Nov 29th, 2022 - Rationale: Myelin sheath is an important structure to maintain normal functions of the nerves. Nerve Injury-Induced Protein 2 (Ninj2) was found upregulated in Schwann cells (SC) upon injury. However, whether and how Ninj2 plays a role in myelination remain unknown. Methods: In this study, we use transmission electron microscope imaging, immunofluorescent imaging, and behavioral tests to show th...

Structures of the holo CRISPR RNA-guided transposon integration complex.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9876797
Nature Park JU, Tsai AW et. al.

Nov 29th, 2022 - CRISPR-associated transposons (CAST) are programmable mobile genetic elements that insert large DNA cargos using an RNA-guided mechanism1-3. CAST elements contain multiple conserved proteins: a CRISPR effector (Cas12k or Cascade), a AAA+ regulator (TnsC), a transposase (TnsA-TnsB) and a target-site-associated factor (TniQ). These components are thought to cooperatively integrate DNA via formati...

Structural basis of tankyrase activation by polymerization.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9712121
Nature Pillay N, Mariotti L et. al.

Nov 24th, 2022 - The poly-ADP-ribosyltransferase tankyrase (TNKS, TNKS2) controls a wide range of disease-relevant cellular processes, including WNT-β-catenin signalling, telomere length maintenance, Hippo signalling, DNA damage repair and glucose homeostasis1,2. This has incentivized the development of tankyrase inhibitors. Notwithstanding, our knowledge of the mechanisms that control tankyrase activity has re...

Structured cerebellar connectivity supports resilient pattern separation.
https://doi.org/10.1038/s41586-022-05471-w
Nature Nguyen TM, Thomas LA et. al.

Nov 24th, 2022 - The cerebellum is thought to help detect and correct errors between intended and executed commands1,2 and is critical for social behaviours, cognition and emotion3-6. Computations for motor control must be performed quickly to correct errors in real time and should be sensitive to small differences between patterns for fine error correction while being resilient to noise7. Influential theories ...

Intra-annual fluctuation in morphology and microfibril angle of tracheids revealed by n...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9665381
PloS One; Kita Y, Awano T et. al.

Nov 16th, 2022 - Woody cells, such as tracheids, fibers, vessels, rays etc., have unique structural characteristics such as nano-scale ultrastructure represented by multilayers, microfibril angle (MFA), micro-scale anatomical properties and spatial arrangement. Simultaneous evaluation of the above indices is very important for their adequate quantification and extracting the effects of external stimuli from the...

CHARACTERIZATION OF SPERMATOZOON ULTRASTRUCTURE IN TETRAGONOCEPHALUM SP. (CESTODA: LECA...
https://doi.org/10.1645/22-42
The Journal of Parasitology; Cielocha JJ, Martinez E et. al.

Oct 28th, 2022 - The Lecanicephalidea represents one of 11 currently recognized elasmobranch-hosted tapeworm lineages. It is quite speciose, with nearly 100 validly recognized species to date. Yet spermatozoon features have been fully characterized for only a single species; spermatozoon characters for a second species were previously included in a data matrix used to infer phylogenetic relationships among cest...

Cryo-EM structure of the SEA complex.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9646525
Nature Tafur L, Hinterndorfer K et. al.

Oct 27th, 2022 - The SEA complex (SEAC) is a growth regulator that acts as a GTPase-activating protein (GAP) towards Gtr1, a Rag GTPase that relays nutrient status to the Target of Rapamycin Complex 1 (TORC1) in yeast1. Functionally, the SEAC has been divided into two subcomplexes: SEACIT, which has GAP activity and inhibits TORC1, and SEACAT, which regulates SEACIT2. This system is conserved in mammals: the GA...

Structural basis of actin filament assembly and aging.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9646518
Nature Oosterheert W, Klink BU et. al.

Oct 27th, 2022 - The dynamic turnover of actin filaments (F-actin) controls cellular motility in eukaryotes and is coupled to changes in the F-actin nucleotide state1-3. It remains unclear how F-actin hydrolyses ATP and subsequently undergoes subtle conformational rearrangements that ultimately lead to filament depolymerization by actin-binding proteins. Here we present cryo-electron microscopy structures of F-...

Bending forces and nucleotide state jointly regulate F-actin structure.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9646526
Nature Reynolds MJ, Hachicho C et. al.

Oct 27th, 2022 - ATP-hydrolysis-coupled actin polymerization is a fundamental mechanism of cellular force generation1-3. In turn, force4,5 and actin filament (F-actin) nucleotide state6 regulate actin dynamics by tuning F-actin's engagement of actin-binding proteins through mechanisms that are unclear. Here we show that the nucleotide state of actin modulates F-actin structural transitions evoked by bending for...

Automated synapse-level reconstruction of neural circuits in the larval zebrafish brain.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9636024
Nature Methods; Svara F, Förster D et. al.

Oct 26th, 2022 - Dense reconstruction of synaptic connectivity requires high-resolution electron microscopy images of entire brains and tools to efficiently trace neuronal wires across the volume. To generate such a resource, we sectioned and imaged a larval zebrafish brain by serial block-face electron microscopy at a voxel size of 14 × 14 × 25 nm3. We segmented the resulting dataset with the flood-filling net...