Prediction of protein assemblies, the next frontier: The CASP14-CAPRI experiment.

We present the results for CAPRI Round 50, the fourth joint CASP-CAPRI protein assembly prediction challenge. The Round comprised a total of twelve targets, including six dimers, three trimers, and three higher-order oligomers. Four of these were easy targets, for which good structural templates were available either for the full assembly, or for the main interfaces (of the higher-order oligomers). Eight were difficult targets for which only distantly related templates were found for the individual subunits. Twenty-five CAPRI groups including eight automatic servers submitted ~1250 models per target. Twenty groups including six servers participated in the CAPRI scoring challenge submitted ~190 models per target. The accuracy of the predicted models was evaluated using the classical CAPRI criteria. The prediction performance was measured by a weighted scoring scheme that takes into account the number of models of acceptable quality or higher submitted by each group as part of their five top-ranking models. Compared to the previous CASP-CAPRI challenge, top performing groups submitted such models for a larger fraction (70-75%) of the targets in this Round, but fewer of these models were of high accuracy. Scorer groups achieved stronger performance with more groups submitting correct models for 70-80% of the targets or achieving high accuracy predictions. Servers performed less well in general, except for the MDOCKPP and LZERD servers, who performed on par with human groups. In addition to these results, major advances in methodology are discussed, providing an informative overview of where the prediction of protein assemblies currently stands.

Biological Insights from Schizophrenia-associated Loci in Ancestral Populations.

Large-scale genome-wide association studies of schizophrenia have uncovered hundreds of associated loci but with extremely limited representation of African diaspora populations. We surveyed electronic health records of 200,000 individuals of African ancestry in the Million Veteran and All of Us Research Programs, and, coupled with genotype-level data from four case-control studies, realized a combined sample size of 13,012 affected and 54,266 unaffected persons. Three genome-wide significant signals - near PLXNA4 , PMAIP1 , and TRPA1 - are the first to be independently identified in populations of predominantly African ancestry. Joint analyses of African, European, and East Asian ancestries across 86,981 cases and 303,771 controls, yielded 376 distinct autosomal loci, which were refined to 708 putatively causal variants via multi-ancestry fine-mapping. Utilizing single-cell functional genomic data from human brain tissue and two complementary approaches, transcriptome-wide association studies and enhancer-promoter contact mapping, we identified a consensus set of 94 genes across ancestries and pinpointed the specific cell types in which they act. We identified reproducible associations of schizophrenia polygenic risk scores with schizophrenia diagnoses and a range of other mental and physical health problems. Our study addresses a longstanding gap in the generalizability of research findings for schizophrenia across ancestral populations, underlining shared biological underpinnings of schizophrenia across global populations in the presence of broadly divergent risk allele frequencies.

Robust 3D modeling reveals spatiosyntenic properties of animal genomes.

Animal genomes are organized into chromosomes that are remarkably conserved in their gene content, forming distinct evolutionary units (synteny). Using versatile chromosomal modeling, we infer three-dimensional topology of genomes from representative clades spanning the earliest animal diversification. We apply a partitioning approach using interaction spheres to compensate for varying quality of topological data. Using comparative genomics approaches, we test whether syntenic signal at gene pair, local, and whole chromosomal scale is reflected in the reconstructed spatial organization. We identify evolutionarily conserved three-dimensional networks at all syntenic scales revealing novel evolutionarily maintained interactors associated with known conserved local gene linkages (such as hox). We thus present evidence for evolutionary constraints that are associated with three-, rather than just two-, dimensional animal genome organization, which we term spatiosynteny. As more accurate topological data become available, together with validation approaches, spatiosynteny may become relevant in understanding the functionality behind the observed conservation of animal chromosomes.

Multi-omic profiling of the developing human cerebral cortex at the single-cell level.

The cellular complexity of the human brain is established via dynamic changes in gene expression throughout development that is mediated, in part, by the spatiotemporal activity of cis-regulatory elements (CREs). We simultaneously profiled gene expression and chromatin accessibility in 45,549 cortical nuclei across six broad developmental time points from fetus to adult. We identified cell type-specific domains in which chromatin accessibility is highly correlated with gene expression. Differentiation pseudotime trajectory analysis indicates that chromatin accessibility at CREs precedes transcription and that dynamic changes in chromatin structure play a critical role in neuronal lineage commitment. In addition, we mapped cell type-specific and temporally specific genetic loci implicated in neuropsychiatric traits, including schizophrenia and bipolar disorder. Together, our results describe the complex regulation of cell composition at critical stages in lineage determination and shed light on the impact of spatiotemporal alterations in gene expression on neuropsychiatric disease.

The role of bivalent ions in the regulation of D-loop extension mediated by DMC1 during meiotic recombination.

During meiosis, programmed DNA double-strand breaks (DSBs) are repaired by homologous recombination. DMC1, a conserved recombinase, plays a central role in this process. DMC1 promotes DNA strand exchange between homologous chromosomes, thus creating the physical linkage between them. Its function is regulated not only by several accessory proteins but also by bivalent ions. Here, we show that whereas calcium ions in the presence of ATP cause a conformational change within DMC1, stimulating its DNA binding and D-loop formation, they inhibit the extension of the invading strand within the D-loop. Based on structural studies, we have generated mutants of two highly conserved amino acids - E162 and D317 - in human DMC1, which are deficient in calcium regulation. In vivo studies of their yeast homologues further showed that they exhibit severe defects in meiosis, thus emphasizing the importance of calcium ions in the regulation of DMC1 function and meiotic recombination.

Emergence of novel cephalopod gene regulation and expression through large-scale genome reorganization.

Coleoid cephalopods (squid, cuttlefish, octopus) have the largest nervous system among invertebrates that together with many lineage-specific morphological traits enables complex behaviors. The genomic basis underlying these innovations remains unknown. Using comparative and functional genomics in the model squid Euprymna scolopes, we reveal the unique genomic, topological, and regulatory organization of cephalopod genomes. We show that coleoid cephalopod genomes have been extensively restructured compared to other animals, leading to the emergence of hundreds of tightly linked and evolutionary unique gene clusters (microsyntenies). Such novel microsyntenies correspond to topological compartments with a distinct regulatory structure and contribute to complex expression patterns. In particular, we identify a set of microsyntenies associated with cephalopod innovations (MACIs) broadly enriched in cephalopod nervous system expression. We posit that the emergence of MACIs was instrumental to cephalopod nervous system evolution and propose that microsyntenic profiling will be central to understanding cephalopod innovations.