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Biology subjects

Matsumura, H.

Publications and source records attributed to Matsumura, H..

15 recordsLinked to original sources

Multiheme selenoenzyme essential for elemental sulfur respiration

Microbial reduction of elemental sulfur is a pivotal process in the global sulfur cycle1. Insoluble elemental sulfur can serve as a terminal electron acceptor during anaerobic respiration, producing sulfide2,3. However, the molecular mechanisms underlying sulfur reduction remain poorly understood. Here we show that an evolutionarily conserved multiheme cytochrome c selenoprotein (MccSep) is essential for elemental sulfur reduction in a sulfur-respiring bacterium. Our biochemical and structural analyses revealed that MccSep comprises four identical subunits, each containing five c-type hemes and one selenocysteine residue (U325). The enzyme catalyzes polysulfide reduction at a unique active site, where C239 coordinates with the heme iron center, while U325 plays a crucial role in the catalytic process. Genetic analysis further revealed the critical roles of U325 and C239 in driving in vivo elemental sulfur respiration. These findings unveiled a selenium-sulfur-dependent catalytic chemistry on a heme center during polysulfide reduction, expanding the scope of biological catalysis and deepening our molecular understanding of bacterial sulfur respiration.

microbiology↗

Chloroplast genome editing of Rubisco boosts photosynthesis and plant growth

Photosynthetic inefficiencies limit the productivity and sustainability of crop production and the resilience of agriculture to future societal and environmental challenges. Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) has inherently low catalytic efficiency, making it a key target for photosynthesis and crop improvement. However, introducing mutations to the chloroplast-encoded Rubisco large subunit (rbcL), which contains the enzymes catalytic sites, is technically challenging. In this study, we successfully generated a range of chloroplast-genome-edited Arabidopsis thaliana plants targeting rbcL by a targeted base editor, ptpTALECD. The M309I and D397N substitutions in rbcL resulted in an increased Rubisco catalytic rate (kcat) without any reductions of Rubisco content, thereby enhancing photosynthetic rates and plant growth under both current atmospheric CO2 concentrations (i.e., 381 mol mol-1) and projected future concentrations (i.e., 549 mol mol-1). Cryo-electron microscopy (cryo-EM) structural analysis showed that the M309I and D397N substitutions, although located far from the catalytic site, induce structural alterations in the catalytic (60s) loops. Our findings highlight the potential of Rubisco engineering to improve plant photosynthesis and growth, and underscore the unique opportunities that chloroplast genome editing offers for enhancing photosynthesis and crop productivity and reducing atmospheric CO2 levels in a non-GMO context.

plant biology↗

Structural basis for the interaction between the bacterial cell division proteins FtsZ and ZapA

Cell division in most bacteria is regulated by the tubulin homolog FtsZ as well as ZapA, a FtsZ-associated protein. However, how FtsZ and ZapA function coordinately has remained elusive. Here we report the cryo-electron microscopy structure of the ZapA-FtsZ complex. The complex forms an asymmetric ladder-like structure, in which the double antiparallel FtsZ protofilament on one side and a single protofilament on the other side are tethered by ZapA tetramers. In the complex, the extensive interactions of FtsZ with ZapA cause a structural change of the FtsZ protofilament, and the formation of the double FtsZ protofilament increases electrostatic repulsion. High-speed atomic force microscopy analysis revealed cooperative interactions of ZapA with FtsZ at a molecular level. Our findings not only provide a structural basis for the interaction between FtsZ and ZapA but also shed light on how ZapA binds to FtsZ protofilaments without disturbing FtsZ dynamics to promote cell division.

molecular biology↗

Conserved loop of a phase modifier endows protein condensates with fluidity

Dipeptide repeats (DPRs) that are gene products from abnormal hexanucleotide repeat expansion in C9orf72 trigger amyotrophic lateral sclerosis (ALS) through unknown mechanism. This study highlights, importin Karyopherin{beta}2 (Kap{beta}2), which is responsible for nuclear transport and phase modification of RNA-binding proteins (RBPs), as a major DPR target. We demonstrate DPR accumulation in the nucleus via Kap{beta}2-mediated transport, which results in dose-dependent toxicity observed in nematode and yeast models. In vitro interaction studies exploiting chemical probe arrays and biophysical measurements reveal multivalent DPR binding to Kap{beta}2, including at the conserved acidic loop. Refractive index and fluorescence imaging coupled with biochemical assays unveiled that binding of excess DPRs to the acidic loop turns a phase modifier Kap{beta}2 into phase disrupter, resulting more condensed and viscous RBP condensates. Our findings provides molecular insight into C9orf72-ALS related to age and repeat expansion.

biochemistry↗

Super homotypic targeting by exosome surface engineering

Homotypic targeting is the inherent ability of cells for preferential interaction with cells of similar or identical types, a phenomenon commonly seen in cell adhesion, tissue formation, and immune responses. Unfortunately, its full potential remains largely untapped. Here we introduce an approach to drastically boost the homotypic targeting capabilities of cells via exosomes (nanoscale extracellular vesicles secreted by cells). By engineering exosome surfaces with lanthanides, we amplify specific cell-exosome interactions by more than 25-fold, significantly accelerating the selective capture of exosomes by cells of the same lineage. This substantial enhancement in cellular homophilicity opens up an entirely new class of applications, two of which we showcase here with unprecedented performance: using cells to detect specific exosomes and using exosomes to detect specific cells. The concept of "super homotypic targeting" offers enormous potential to transform cancer diagnostics, immunotherapy, targeted drug delivery, tissue engineering, and vaccine development.

cell biology↗

Palaeoproteomic investigation of an ancient human skeleton with abnormal deposition of dental calculus

Detailed investigation of extremely severe pathological conditions in ancient human skeletons is important as it could shed light on the breadth of potential interactions between humans and disease etiologies in the past. Here, we applied palaeoproteomics to investigate an ancient human skeletal individual with severe oral pathology, focusing our research on bacterial pathogenic factors and host defense response. This female skeleton, from the Okhotsk period (i.e., 5th-13th century) of Northern Japan, poses relevant amounts of abnormal dental calculus deposition and exhibits oral dysfunction due to severe periodontal disease. A shotgun mass-spectrometry analysis identified 81 human proteins and 15 bacterial proteins from the calculus of the subject. We identified two pathogenic or bioinvasive proteins originating from two of the three "red complex" bacteria, the core species associated with severe periodontal disease in modern humans, as well as two additional bioinvasive proteins of periodontal-associated bacteria. Moreover, we discovered defense response system-associated human proteins, although their proportion was mostly similar to those reported in ancient and modern human individuals with lower calculus deposition. These results suggest that the bacterial etiology was similar and the host defense response was not necessarily more intense in ancient individuals with significant amounts of abnormal dental calculus deposition.

evolutionary biology↗

Discovery of the apiosyltransferase, celery UGT94AX1 that catalyzes the biosynthesis of a flavone glycoside, apiin

Apiose is a unique branched-chain pentose found in plant glycosides and a key component of the cell wall-polysaccharide pectin and other specialized metabolites. More than 1,200 plant-specialized metabolites contain apiose residues, represented by apiin, a distinctive flavone glycoside found in celery and parsley in the family Apiaceae. The physiological functions of apiin remain obscure, partly due to our lack of knowledge on apiosyltransferase during apiin biosynthesis. Here, we identified celery UGT94AX1 (AgApiT) as a novel apiosyltransferase, responsible for catalyzing the last sugar-modification step in apiin biosynthesis. AgApiT showed strict substrate specificity for the sugar donor, UDP-apiose, and moderate specificity for acceptor substrates, thereby producing various apiose-containing flavone glycosides in celery. Homology modeling of AgApiT with UDP-apiose, followed by site-directed mutagenesis experiments, identified unique Ile139, Phe140, and Leu356 residues in AgApiT, which are seemingly crucial for the recognition of UDP-apiose in the sugar donor pocket. Sequence comparison and molecular phylogenetic analysis of celery glycosyltransferases paralogous to AgApiT suggested that AgApiT is the sole apiosyltransferase-encoding gene in the celery genome. This is the first report on the identification of a plant apiosyltransferase gene that will enhance our understanding of the physio-ecological functions of apiose and apiose-containing compounds.

biochemistry↗

High-resolution structure of a microtubule-like tube composed of FtsZ-monobody complexes

FtsZ, a bacterial tubulin homologue, forms protofilaments and the Z-ring, which acts as a scaffold for accessory proteins during cell division. Although various studies have revealed its molecular mechanisms, the lack of high-resolution solution structures has hindered the understanding of the detailed mechanisms. Here, we developed a monobody (Mb) that binds FtsZs from Escherichia coli and Klebsiella pneumoniae (KpFtsZ) without affecting their GTPase activities. When expressed in E. coli cells, the Mb did not inhibit Z-ring formation but did inhibit cell division. The crystal structures of the KpFtsZ-Mb complexes revealed the epitope, and the cryoEM structure at 2.67 [A] resolution showed a double helical tube consisting of two KpFtsZ protofilaments stabilized by the Mb filling interfilament gaps. Our structural analyses highlight the similarity between the microtubule and the FtsZ tube and the importance of the plasticity of FtsZ protofilaments.

molecular biology↗

The Genomic Formation of Human Populations in East Asia

The deep population history of East Asia remains poorly understood due to a lack of ancient DNA data and sparse sampling of present-day people. We report genome-wide data from 191 individuals from Mongolia, northern China, Taiwan, the Amur River Basin and Japan dating to 6000 BCE - 1000 CE, many from contexts never previously analyzed with ancient DNA. We also report 383 present-day individuals from 46 groups mostly from the Tibetan Plateau and southern China. We document how 6000-3600 BCE people of Mongolia and the Amur River Basin were from populations that expanded over Northeast Asia, likely dispersing the ancestors of Mongolic and Tungusic languages. In a time transect of 89 Mongolians, we reveal how Yamnaya steppe pastoralist spread from the west by 3300-2900 BCE in association with the Afanasievo culture, although we also document a boy buried in an Afanasievo barrow with ancestry entirely from local Mongolian hunter-gatherers, representing a unique case of someone of entirely non-Yamnaya ancestry interred in this way. The second spread of Yamnaya-derived ancestry came via groups that harbored about a third of their ancestry from European farmers, which nearly completely displaced unmixed Yamnaya-related lineages in Mongolia in the second millennium BCE, but did not replace Afanasievo lineages in western China where Afanasievo ancestry persisted, plausibly acting as the source of the early-splitting Tocharian branch of Indo-European languages. Analyzing 20 Yellow River Basin farmers dating to [~]3000 BCE, we document a population that was a plausible vector for the spread of Sino-Tibetan languages both to the Tibetan Plateau and to the central plain where they mixed with southern agriculturalists to form the ancestors of Han Chinese. We show that the individuals in a time transect of 52 ancient Taiwan individuals spanning at least 1400 BCE to 600 CE were consistent with being nearly direct descendants of Yangtze Valley first farmers who likely spread Austronesian, Tai-Kadai and Austroasiatic languages across Southeast and South Asia and mixing with the people they encountered, contributing to a four-fold reduction of genetic differentiation during the emergence of complex societies. We finally report data from Jomon hunter-gatherers from Japan who harbored one of the earliest splitting branches of East Eurasian variation, and show an affinity among Jomon, Amur River Basin, ancient Taiwan, and Austronesian-speakers, as expected for ancestry if they all had contributions from a Late Pleistocene coastal route migration to East Asia.

genomics↗

Virtual-freezing fluorescence imaging flow cytometry

By virtue of the combined merits of flow cytometry and fluorescence microscopy, imaging flow cytometry (IFC) has become an established tool for cell analysis in diverse biomedical fields such as cancer biology, microbiology, immunology, hematology, and stem cell biology. However, the performance and utility of IFC are severely limited by the fundamental trade-off between throughput, sensitivity, and spatial resolution. For example, at high flow speed (i.e., high throughput), the integration time of the image sensor becomes short, resulting in reduced sensitivity or pixel resolution. Here we present an optomechanical imaging method that overcomes the trade-off by virtually "freezing" the motion of flowing cells on the image sensor to effectively achieve 1,000 times longer exposure time for microscopy-grade fluorescence image acquisition. Consequently, it enables high-throughput IFC of single cells at >10,000 cells/s without sacrificing sensitivity and spatial resolution. The availability of numerous information-rich fluorescence cell images allows high-dimensional statistical analysis and accurate classification with deep learning, as evidenced by our demonstration of unique applications in hematology and microbiology.

cell biology↗

Long-read bitter gourd (Momordica charantia) genome and the genomic architecture of domestication

Bitter gourd (Momordica charantia) is a vegetable and medicinal plant of the family Cucurbitaceae. Here we report a chromosome-level assembly, with highest contig N50 (close to 10 Mb) and proportion of sequences placed on chromosomes (96%) in Cucurbitaceae. Population resequencing revealed the divergence between wild and cultivars at about 6000 years ago. Different cultivar groups have distinct allelic compositions in loci associated with domestication traits, suggesting phenotypic changes were achieved by allele frequency shifts in independent loci. Noticeably, one candidate locus for fruit size locates within a region missing from a recent Illumina-based assembly. Despite breeding efforts to increase female flower proportion, the gynoecy locus exhibits high variation within and low differentiation between wild and cultivar groups, likely because artificial directional selection could not overwhelm natural balancing selection. Our study provides resources to further investigate the genetic architecture of bitter gourd as well highlights the importance of a well-assembled genome.

genomics↗

Toxic PR poly-dipeptides encoded by the C9orf72 repeat expansion target Kapβ2 and dysregulate phase separation of low-complexity domains

Low-complexity (LC) domains of proteins are found in about one fifth of human proteome, and a group of LC-domains form labile cross-{beta} polymers and liquid-like droplets. Polymers and droplets formed from LC-domains are dynamically regulated by posttranslational modifications and molecular chaperones including nuclear transport receptors. Repeat expansion in the first intron of a gene designated C9orf72, which is the most prevalent form of familial amyotrophic lateral sclerosis (ALS), causes nucleocytoplasmic transport deficit, however, the detailed mechanism remains unsolved. Here we show that the proline:arginine (PR) poly-dipeptides encoded by the C9orf72 repeat expansion bound nuclear transport receptor Kap{beta}2 through its nuclear localization signal (NLS) recognition motif, and inhibited the ability of Kap{beta}2 to melt fused in sarcoma (FUS) droplets by competing interaction with FUS. The findings in this study offer mechanistic insights as to how the C9orf72 repeat expansion disables nucleocytoplasmic transport and causes neurodegenerative diseases.

molecular biology↗

Identification of candidate flowering and sex genes in white Guinea yam (D. rotundata Poir.) by SuperSAGE transcriptome profiling

Dioecy (distinct male and female individuals) combined with scarce to non-flowering are common features of cultivated yam (Dioscorea spp.). However, the molecular mechanisms underlying flowering and sex determination in Dioscorea are unknown. We conducted SuperSAGE transcriptome profiling of male, female and monoecious individuals to identify flowering and sex-related genes in white Guinea yam (D. rotundata). SuperSAGE analysis generated a total of 20,236 unique tags, of which 13,901 were represented by a minimum of 10 tags. Of these, 88 tags were significantly differentially expressed in male, female and monoecious plants. Of the 88 differentially expressed SuperSAGE tags, 18 corresponded to genes previously implicated in flower development and sex determination in multiple plant species. We validated the SuperSAGE data with quantitative real-time PCR (qRT-PCR)-based analysis of the expression of four candidate genes. Our findings suggest that mechanisms of flowering and sex determination are likely conserved in Dioscorea. We further investigated the flowering patterns of 1938 D. rotundata accessions representing diverse geographical origins over two years, revealing that over 85% of the accessions are either male or non-flowering, and that less than 15% are female, while monoecious plants are rare. Intensity of flowering appeared to be a function of sex, with male plants flowering more abundantly than female ones. Candidate genes identified in this study can be targeted with the aim to induce regular flowering in poor to non-flowering cultivars. Findings of the study provide important inputs for further studies aiming to overcome the challenge of flowering in yams and to improve the efficiency of yam breeding.

plant biology↗

Ancient genomes document multiple waves of migration in Southeast Asian prehistory

Southeast Asia is home to rich human genetic and linguistic diversity, but the details of past population movements in the region are not well known. Here, we report genome-wide ancient DNA data from thirteen Southeast Asian individuals spanning from the Neolithic period through the Iron Age (4100-1700 years ago). Early agriculturalists from Man Bac in Vietnam possessed a mixture of East Asian (southern Chinese farmer) and deeply diverged eastern Eurasian (hunter-gatherer) ancestry characteristic of Austroasiatic speakers, with similar ancestry as far south as Indonesia providing evidence for an expansive initial spread of Austroasiatic languages. In a striking parallel with Europe, later sites from across the region show closer connections to present-day majority groups, reflecting a second major influx of migrants by the time of the Bronze Age.

genetics↗

High prevalence of the antibody against Syncytin-1 in schizophrenia

Both genetic and environmental factors have been considered causative agents for schizophrenia (SZ). However, no single gene has been shown responsible for the development of SZ. Furthermore, the pathophysiological roles of environmental factors including psychological stress, autoimmunity, and microbial infection have not been fully understood. Previous studies have suggested the involvement of one of the human endogenous retroviruses (HERVs), HERV-W, in SZ. In this study, prevalence of antibodies against the HERV-W Syncytin-1 protein was examined using a newly developed ELISA test. Fifty percent of patients with SZ (24 out of 48 cases) were antibody-positive, with a specificity of greater than 95% (less than 5% of control cases, 3 out of 79). No significant effect of medication was evident, nor did any SZ cases become seropositive after diagnosis. These findings indicate a possible involvement of HERV-W expression in the development of SZ and support its applicability to laboratory diagnoses.

neuroscience↗