Science

The large-scale synthesis of high-quality thin films with extensive tunability derived from molecular building blocks will advance the development of artificial solids with designed functionalities. We report the synthesis of two-dimensional (2D) porphyrin polymer films with wafer-scale homogeneity in the ultimate limit of monolayer thickness by growing films at a sharp pentane/water interface, which allows the fabrication of their hybrid superlattices. Laminar assembly polymerization of porphyrin monomers could form monolayers of metal-organic frameworks with Cu2+ linkers or covalent organic frameworks with terephthalaldehyde linkers...

The metabolic characteristics of tumors present significant hurdles to immune cell function and cancer immunotherapy. Using a novel glutamine antagonist, we metabolically dismantled the immunosuppressive microenvironment of tumors. We demonstrate that glutamine blockade in tumor-bearing mice suppresses oxidative and glycolytic metabolism of cancer cells, leading to decreased hypoxia, acidosis, and nutrient depletion. In contrast, effector T cells responded to glutamine antagonism by markedly upregulating oxidative metabolism and adopting a long-lived, highly-activated phenotype...

The emergence of drug resistance limits the efficacy of targeted therapies in human tumors. The prevalent view is that resistance is a fait accompli: when treatment is initiated, cancers already contain drug-resistant mutant cells. Bacteria exposed to antibiotics transiently increase their mutation rates (adaptive mutability), thus improving the likelihood of survival. We investigated whether human colorectal cancer (CRC) cells likewise exploit adaptive mutability to evade therapeutic pressure. We found that epidermal growth factor receptor (EGFR)/BRAF inhibition down-regulates mismatch repair (MMR) and homologous recombination (HR) DNA repair genes, and concomitantly up-regulates error-prone polymerases in drug-tolerant (persister) cells...

Gastrulation is a key event in embryonic development when the germ layers are specified and the basic animal body plan is established. The complexities of primate gastrulation remain a mystery due to the difficulties in accessing primate embryos at this stage. Here, we report the establishment of an in vitro culture (IVC) system which supports the continuous development of cynomolgus monkey blastocysts beyond early gastrulation and to 20 days post fertilization. The IVC embryos highly recapitulated the key events of in vivo early post-implantation development, including segregation of the epiblast and hypoblast, formation of the amniotic and yolk sac cavities, appearance of the primordial germ cells, and establishment of the anterior-posterior axis...

The transition from peri-implantation to gastrulation in mammals entails the specification and organization of the lineage progenitors into a body plan. Technical and ethical challenges have limited understanding of the cellular and molecular mechanisms underlying this transition. Here, we established a culture system that enabled the development of cynomolgus monkey embryos in vitro for up to 20 days. Cultured embryos underwent key primate developmental stages, including lineage segregation, bi-laminar disc formation, amniotic and yolk sac cavitation, and primordial germ cell-like cell (PGCLC) differentiation...

Vaccine induction of broadly neutralizing antibodies (bnAbs) to human immunodeficiency virus (HIV) remains a major challenge. Germline-targeting immunogens hold promise for initiating the induction of certain bnAb classes; yet for most bnAbs, a strong dependence on antibody heavy chain complementarity determining region 3 (HCDR3) is a major barrier. Exploiting ultra-deep human antibody sequencing data, we identified a diverse set of potential antibody precursors for a bnAb with dominant HCDR3 contacts. We then developed HIV envelope trimer-based immunogens that primed responses from rare bnAb-precursor B cells in a mouse model, and in ex-vivo screens bound a range of potential bnAb-precursor human naive B cells...

The RSC complex remodels chromatin structure and regulates gene transcription. We report the cryoEM structure of yeast RSC bound to the nucleosome. RSC is delineated into the ATPase motor, the actin-related-protein (ARP) module, and the substrate-recruitment module (SRM). RSC binds the nucleosome mainly through the motor, with the auxiliary subunit Sfh1 engaging the H2A-H2B acidic patch to enable nucleosome ejection. SRM is organized into three substrate-binding lobes poised to bind their respective nucleosomal epitopes...

Tissues rely on stem cells (SCs) for homeostasis and wound-repair. SCs reside in specialized microenvironments (niches) whose complexities and roles in orchestrating tissue growth are still unfolding. Here, we identify lymphatic capillaries as critical SC-niche components. In skin, lymphatics form intimate networks around hair follicle (HF) SCs. When HFs regenerate, lymphatic:SC connections become dynamic. We unravel a secretome switch within SCs that controls lymphatic behavior. Resting SCs express Angiopoietin-like 7 ( Angptl7) , promoting lymphatic drainage...

The tumor suppressor folliculin (FLCN) enables nutrient-dependent activation of the mechanistic target of rapamycin complex 1 (mTORC1) protein kinase via its guanosine triphosphatase (GTPase) Activating Protein (GAP) activity toward the GTPase RagC. Concomitant with mTORC1 inactivation by starvation, FLCN relocalizes from the cytosol to lysosomes. To determine the lysosomal function of FLCN, we reconstituted the lysosomal FLCN complex (LFC) containing FLCN, its partner FLCN-interacting protein 2 (FNIP2), the RagAGDP :RagCGTP GTPases as they exist in the starved state with their lysosomal anchor Ragulator complex, and determined its cryo-EM structure to 3...

We report a time-calibrated stratigraphic section in Colorado that contains unusually complete fossils of mammals, reptiles, and plants, and elucidates the drivers and tempo of biotic recovery during the poorly known first million years after the Cretaceous-Paleogene mass extinction (KPgE). Within ~100 thousand years (ka) post-KPgE, mammalian taxonomic richness doubled and maximum mammalian body mass increased to near pre-KPgE levels. A three-fold increase in maximum mammalian body mass and dietary niche specialization occurred at ~300 ka post-KPgE, concomitant with increased megafloral standing species richness...

The dense circuit structure of mammalian cerebral cortex is still unknown. With developments in three-dimensional electron microscopy, the imaging of sizeable volumes of neuropil has become possible, but dense reconstruction of connectomes is the limiting step. We reconstructed a volume of ~500,000 μm3 from layer 4 of mouse barrel cortex, ~300 times larger than previous dense reconstructions from the mammalian cerebral cortex. The connectomic data allowed the extraction of inhibitory and excitatory neuron subtypes that were not predictable from geometric information...

ParABS systems facilitate chromosome segregation and plasmid partitioning in bacteria and archaea. ParB protein binds centromeric parS DNA sequences and spreads to flanking DNA. We show that ParB is an enzyme that hydrolyzes cytidine triphosphate (CTP) to diphosphate (CDP). parS DNA stimulates cooperative CTP binding by ParB and CTP hydrolysis. A nucleotide co-crystal structure elucidates the catalytic center of the dimerization-dependent ParB CTPase. Single-molecule imaging and biochemical assays recapitulate features of ParB spreading from parS in the presence but not absence of CTP...

We present histological and molecular analyses of the developing human cerebellum from 30 days after conception to 9 months after birth. Differences in developmental patterns between humans and mice include spatiotemporal expansion of both ventricular and rhombic lip primary progenitor zones to include subventricular zones containing basal progenitors. The human rhombic lip persists longer through cerebellar development than in the mouse and undergoes morphological changes to form a progenitor pool in the posterior lobule, which is not seen in other organisms, not even in the nonhuman primate, the macaque...

African swine fever virus (ASFV) is a giant and complex DNA virus that causes a highly contagious and often lethal swine disease without vaccine available. Using an optimized image reconstruction strategy, we solved the ASFV capsid structure up to 4.1-angstroms, which is built from 17,280 proteins, including one major (p72) and four minor capsid proteins (M1249L, p17, p49 and H240R), organized into pentasymmetrons and trisymmetrons. The atomic structure of the p72 informs putative conformational epitopes, distinguishing ASFV from other nucleocytoplasmic large DNA viruses (NCLDV)...

The mTORC1 protein kinase regulates growth in response to nutrients and growth factors. Nutrients promote its translocation to the lysosomal surface, where its Raptor subunit interacts with the Rag GTPase-Ragulator complex. Nutrients switch the heterodimeric Rag GTPases between four different nucleotide binding states, only one of which (RagA/B•GTP-RagC/D•GDP) permits mTORC1 association. We determined the structure of the supercomplex of Raptor with Rag-Ragulator to 3.2 Å resolution by cryo-electron microscopy...

Transcriptome data can facilitate the interpretation of the effects of rare genetic variants. Here, we introduce ANEVA (analysis of expression variation) to quantify genetic variation in gene dosage from allelic expression (AE) data in a population. Application of ANEVA to the Genotype-Tissues Expression (GTEx) data showed that this variance estimate is robust and correlated with selective constraint in a gene. Using these variance estimates in a dosage outlier test (ANEVA-DOT) applied to AE data from 70 Mendelian muscular disease patients showed accuracy in detecting genes with pathogenic variants in previously resolved cases and led to one confirmed and several potential new diagnoses...

Harvested by advanced technical systems honed over decades of research and development, wind energy has become a mainstream energy resource. However, continued innovation is needed to realize the potential of wind to serve global demand for clean energy. Here, we outline three interdependent, cross-disciplinary grand challenges underpinning this research endeavor. The first is the need for a deeper understanding of the physics of atmospheric flow in the critical zone of plant operation. The second involves science and engineering of the largest dynamic, rotating machines in the world...

Revealing and understanding the mechanisms behind social inequality in prehistoric societies is a major challenge. By combining genome wide data, isotopic evidence as well as anthropological and archaeological data, we go beyond the dominating supra-regional approaches in archaeogenetics to shed light on the complexity of social status, inheritance rules and mobility during the Bronze Age. We apply a deep micro-regional approach and analyze genome wide data of 104 human individuals deriving from farmstead-related cemeteries from the Late Neolithic to the Middle Bronze Age in southern Germany...

First-order relationships between organic matter content and mineral surface area have been widely reported and are implicated in stabilization and long-term preservation of organic matter. However, the nature and stability of organo-mineral interactions and their connection with mineralogical composition, have remained uncertain. Here, we find that continentally derived organic matter of pedogenic origin is stripped from smectite mineral surfaces upon discharge, dispersal, and sedimentation in distal ocean settings...

Sensory systems use stochastic fate specification to increase their repertoire of neuronal types. How these stochastic decisions are coordinated with the development of their targets is unknown. In the Drosophila retina, two subtypes of UV-sensitive R7-photoreceptors are stochastically specified. In contrast, their targets in the brain are specified through a deterministic program. Here, we identify subtypes of the main target of R7, the Dm8 neurons, each specific to the different subtypes of R7s. Dm8 subtypes are produced in excess by distinct neuronal progenitors, independently from R7...