Biology subjects

Sugawara, M.

Publications and source records attributed to Sugawara, M..

6 recordsLinked to original sources

bioRxiv2025

Cyclophilin A-mediated cis/trans isomerization modulates RIN4 to control intracellular rhizobial infection in legumes

In most legume-rhizobium symbioses, rhizobial colonization occurs through host-derived intracellular infection threads, which enable recruitment of compatible rhizobia while presumably modulating the host immune system to prevent rejection. To investigate how legumes regulate immune responses through post-translational mechanisms during the infection, we focused on Cyclophilin A (CyPA), a peptidyl-prolyl cis/trans isomerase. The model legume Lotus japonicus encodes three canonical CyPA genes. Among them, LjCyPA1 was characterized through CRISPR/Cas9-mediated knockout analysis and shown to be important for normal intracellular infection of compatible rhizobia. A gain-of-function LjCyPA1 variant in a soybean cultivar was able to promote symbiosis with not only compatible but also incompatible rhizobia. Structural modeling followed by genetic analysis demonstrated a functional interaction between LjCyPA1 and the immune hub protein LjRIN4. The cis conformation of LjRIN4 promoted intracellular rhizobial infection, while the trans conformation suppressed it. LjCyPA1 acted with the rhizobial type III secretion system (T3SS) which exhibited a cooperative role between host and symbiont in facilitating infection. Phylogenomic analysis showed that conservation of the CyPA1 orthologue is correlated with the trait of intracellular infection in legumes. Our results contribute to the understanding of how legumes accept symbiotic partners while balancing immune responses.

plant biology↗

bioRxiv2025

Neural mechanisms underlying reward processing and social cognition: a replication study with a Japanese sample

Neural functions underlying reward processing and social cognition play a critical role in everyday decision-making. Given that these processes may be shaped by cultural factors, it is essential to examine their cross-cultural generalizability. In this study, we used functional MRI to scan native Japanese speakers as they performed two well-established experimental paradigms: the Monetary Incentive Delay (MID) task for reward processing and the Theory of Mind (ToM) task for social cognition. We successfully replicated previous findings. Specifically, in the MID task, reward expectation and reward outcome were associated with neural activity in the ventral striatum and ventromedial prefrontal cortex. In the ToM task, social cognition was linked to activation in the temporoparietal junction. Notably, the posterior cingulate cortex was engaged in both tasks, suggesting its integrative role across cognitive domains. Together, these results replicate and extend earlier work, supporting the cross-cultural generalizability of the neural mechanisms underlying reward and social cognition, and further validating our fMRI protocol for future research.

neuroscience↗

bioRxiv2025

Unipolar polysaccharide-mediated attachment of the N2O-reducing bacterium Bradyrhizobium ottawaense SG09 to plant roots.

Agricultural soils are an important source of nitrous oxide (N2O), which has greenhouse and ozone-depleting effects. Bradyrhizobium ottawaense SG09 is a nitrogen-fixing rhizobium with high N2O-reducing activity. Rhizobia form symbiotic nodules in leguminous plants. The initial physical attachment of bacteria to plant roots is a critical step in the establishment of symbiotic interactions. In this study, we performed microscopic analysis using DsRed-expressing B. ottawaense SG09. We revealed that B. ottawaense SG09 attached to both the root surface and root hairs via single cellular poles. This polar attachment was observed not only to the symbiotic host soybean, but also to non-leguminous plants, such as Arabidopsis, rice, corn, and wheat. We identified and analyzed the unipolar polysaccharide (upp) gene cluster, which is proposed to be involved in polar attachment of rhizobia, in the genome of B. ottawaense SG09. We established an Arabidopsis-based interaction assay and demonstrated that uppC and uppE play a critical role in attachment to both the root surface and root hairs.

microbiology↗

bioRxiv2025

LINC01503-MP is a Mitochondrial Microprotein That Promotes Cell Proliferation and Oxidative Metabolism.

Long non-coding RNAs (lncRNAs) are well-established as key regulators of gene expression. However, emerging evidence reveals that some lncRNAs can also encode functional microproteins. In this study, we report the identification of an evolutionarily young microprotein encoded by LINC01503, expressed across several human tissues. This microprotein, designated as LINC01503-MP, localises to the mitochondria and exerts a proliferative effect on HCT116 colorectal cancer (CRC) cells. Functional studies reveal that LINC01503-MP regulates mitochondrial oxygen consumption rate, linking its activity to enhanced metabolic functions and cell proliferation. Interactome analyses identified multiple mitochondrial metabolism-related proteins as potential interaction partners. Our findings show that LINC01503-MP plays a role in the proliferative phenotype associated with LINC01503 upregulation in CRC, suggesting the functional significance of evolutionarily young, lncRNA-derived microproteins in cancer progression.

molecular biology↗

bioRxiv2024

Distinct roles of two thalamostriatal systems in learning processes of visual discrimination in common marmosets

The thalamostriatal projections arising from the intralaminar thalamic nuclei (ILN) constitute the principal source of input information to specified subregions of the striatum, a key structure of the cortico-basal ganglia circuitry. However, the roles of primate ILN in cortico-basal ganglia circuit functions remain unclear. Here, we performed immunotoxin-induced selective targeting of two representative structures of the ILN, the parafascicular nucleus (Pf) and centre median nucleus (CM) projecting to the caudate nucleus (Cd) and putamen (Pu), respectively, in common marmosets. Elimination of Pf-Cd neurons resulted in impaired reversal learning of a two-choice visual discrimination task, whereas removal of CM-Pu neurons disturbed the task acquisition. No marked impact of such manipulations was observed on either motor skill learning or spontaneous locomotor activity. Our findings reveal that the two thalamostriatal systems play distinct roles in the learning processes of external cue-dependent decision-making in nonhuman primates.

neuroscience↗

bioRxiv2022

Highly selective transgene expression through double-floxed inverted orientation system by using a unilateral spacer sequence

The double-floxed inverted orientation (DIO) system with adeno-associated viral (AAV) vector provides a beneficial approach to express transgenes in specific cell populations having Cre recombinase. A significant issue with this system is the protection against non-specific expression of transgenes in tissues after vector injection. We here show that Cre-independent recombination in AAV genome carrying the DIO sequence occurs during the production of viral vectors in packaging cells, which results in transgene expression in off-target populations. Introduction of a relatively longer nucleotide sequence between two recognition sites at the unilateral side of the transgene cassette, termed a unilateral spacer sequence (USS), is useful to suppress recombination during the vector production, leading to the protection of non-specific transgene expression with enhanced gene expression selectivity. Our DIO/USS system offers a powerful strategy for highly specific Cre-dependent transgene expression, aiming at various applications for structural and functional analyses of target cell populations.

neuroscience↗