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Gough, C.

Publications and source records attributed to Gough, C..

7 recordsLinked to original sources

Combinatorial regulation of cellular rotation by CUL-3-actomyosin-dependent oriented division, eggshell geometry, and Ras–MAPK signaling during dorsal–ventral axis establishment in Caenorhabditis elegans

Cellular rotation is an understudied mechanism that regulates animal morphogenesis. In C. elegans, the dorsal-ventral axis is established when the two-cell-stage AB cell rotates within the eggshell as it divides, generating the diamond-shaped blastomere arrangement at the four-cell stage that enables distinct cell fate specification. Multiple mechanisms, including actomyosin-dependent oriented division, chiral cortical flow, and eggshell shape, have been proposed to regulate this arrangement, but whether these represent conflicting hypotheses or co-acting mechanisms remains unclear. Here, we show that CUL-3-actomyosin-dependent oriented division, eggshell geometry, and the Ras-MAPK signaling pathway regulate distinct steps of cellular rotation. AB cell rotation occurred in two distinct phases: Phase I during AB cytokinesis and Phase II during cytokinesis of the neighboring P1 cell. Quantitative analysis revealed that CUL-3-actomyosin-dependent oriented division is the only one of these three pathways that regulates the AB division axis before anaphase. Actomyosin-dependent oriented division and eggshell geometry were both required for Phase I rotation, whereas Phase II rotation was independent of eggshell geometry. We further identified the Ras-MAPK signaling pathway as a regulator of AB cell rotation that acts independently of eggshell geometry. Strikingly, the CUL-3-actomyosin-dependent pathway may have two distinct roles: first, specifying the AB division axis, and second, correcting the division axis in all cell types during cytokinesis. Together, these functions contribute significantly to cellular rotation and dorsal-ventral axis establishment.

Cell Biology↗

Aurora kinase A enables collective invasion and metastasis by endowing a leader cell phenotype and stabilizing Eplin-mediated cohesion with follower cells

The metastatic process initiates with collective cell invasion into surrounding tissues and axillary nodes, and subsequent colonization at a distant site. Previously, we found collective invasion is augmented during the G2 cell cycle phase, facilitated through Aurora kinase A (AURKA)-mediated centrosome polarization in the leader cell. Here, we identify cell cycle-associated gene signatures as overrepresented in axilla and liver metastatic sites, with AURKA expression strongly correlated with breast cancer metastasis signatures, and pan-cancer patient survival. Then, we show GFP-AURKA expression endows breast epithelia cells with the ability to form metastatic outgrowths within immune-incompetent chicken embryos. Multi-parametric imaging of wound closure assays reveals phenotypes enabled by, and dependent upon AURKA expression. We discover leader cells express AURKA and acquire front-polarized centrosomes, which differentiates them from other cells in the migrating group. Ectopic expression of GFP-AURKA induces a leader cell phenotype. Conversely, inhibition of AURKA activity alters actin dynamics, promotes turnover of cell contacts, and reduces coordination within migrating groups. Specifically, AURKA interacts with the actin regulator EPLIN, and AURKA inhibition localizes EPLIN to lamellipodia and away from E-cadherin-positive contacts. Inhibiting these necessary roles for AURKA may provide a critical barrier against the metastatic spread of human breast carcinoma cells.

cancer biology↗

A novel pathosystem between Aeschynomene evenia and Aphanomyces euteiches reveals new immune components in quantitative legume root-rot resistance.

Legumes are pivotal for sustainable agriculture, yet their productivity is hindered by soilborne pathogens such as Aphanomyces euteiches. This study introduces Aeschynomene evenia as a novel model to investigate legume immunity and its interplay with Nod factor-independent symbiosis (NFIS). Inoculation of A. evenia accessions with A. euteiches strains revealed a range of quantitative resistance levels. Phenotypic and cytological analyses showed a compatible interaction, including root browning, intracellular colonisation, and oospore production; along with partial resistance traits such as phenolic accumulation at the endodermal barrier. Transcriptomic analyses at 1 and 3 dpi identified 3,403 differentially expressed genes (DEGs), with upregulated genes associated with pathogen perception, immune signalling and specialised metabolite biosynthesis. Kinase-mediated signalling, ROS homeostasis, and WRKY transcription factors were among the most enriched functional categories. Comparative transcriptomics with Medicago truncatula confirmed conserved immune responses, while A. evenia displayed broader transcriptional repression. Integration with symbiotic transcriptomic data revealed overlapping gene signatures, including AeRLCK2 and AeCRK, previously found to be NFIS-specific, as putative dual-function kinases. Aerlck2 and Aecrk mutants exhibited enhanced resistance to A. euteiches, supporting their roles in immune regulation. This work positions A. evenia-A. euteiches as a valuable system to dissect legume quantitative resistance and its intersection with symbiosis.

plant biology↗

Light induces Phytochrome B SUMOylation to recruit the immune regulator NPR1 in nuclear condensates to control immunity in plants

It has long been observed that light perception by phytochromes control plant immunity, however, the underpinning molecular mechanism is less well understood. We demonstrate that light mediated SUMO conjugation to Phytochrome B (PhyB) is critical for increasing cellular salicylic-acid (SA) levels to orchestrate systemic acquired resistance (SAR) upon avirulent bacterial infection. SUMOylation is critical for PhyB nuclear condensate formation during light activated immunity. Light induced PhyB SUMOylation recruits NPR1, through its SUMO interacting motif to nuclear condensates to elevate SA levels for immune responses. In the dark during SAR, elevated SA levels substitute for light to maintain PhyB SUMOylation and immune-related photobody formation by stimulating the degradation of PhyB targeting deSUMOylase, OTS1. SUMOylated PhyB-NPR1 immune photobodies associate with TGA transcription factor associated chromatin to trigger immune gene expression. We unravel a mechanism where SUMOylation can enable light to recruit NPR1 to PhyB nuclear condensates to form immune photobodies to regulate plant immunity. HighlightsO_LILight-dependent immunity in plants relies on the SUMO mediated interaction between the photoreceptor PhyB and the Salicylic Acid (SA) receptor NPR1. C_LIO_LILight induced PhyB SUMOylation recruits NPR1 to nuclear condensates which we identify as immune photobodies that elevate SA levels for immune responses. C_LIO_LIIn darkness, SA can replace light in enabling PhyB-NPR1 immune photobody formation by regulating SUMOylation revealing a SA mediated mechanism for controlling PhyB liquid-liquid phase separation. C_LIO_LISUMO-modified PhyB-NPR1 immune photobodies regulate transcriptional activity of immune associated chromatin to shape defence responses in plants. C_LI

plant biology↗

A Receptor Like Cytoplasmic Kinase evolved in Aeschynomene legumes to mediate Nod-independent rhizobial symbiosis

Many plants interact symbiotically with arbuscular mycorrhizal (AM) fungi to enhance inorganic phosphorus uptake, and legumes also develop a nodule symbiosis with rhizobia for nitrogen acquisition. Establishment and functioning of both symbioses rely on a common plant signaling pathway activated by structurally related Myc- and Nod-factors. Recently, a SPARK Receptor-like-Kinase (RLK)/Receptor-like Cytoplasmic Kinase (RLCK) complex was shown to be essential for AM in both monocot and dicot plants. Here, we show that in Aeschynomene legumes the RLCK component of this receptor complex has evolved following a gene duplication event and mediates a unique nodule symbiosis that is independent of rhizobial Nod factors. In Aeschynomene evenia, AeRLCK2 is crucial for nodule initiation but not for AM. Additionally, AeRLCK2 physically interacts with and is phosphorylated by the Cysteine-rich RLK, AeCRK, also required for nodulation. This work reveals a novel evolutionary origin of this Nod-independent symbiosis from AM.

plant biology↗

Medicago truncatula SOBIR1 controls specificity in the Rhizobium-legume symbiosis

Medicago truncatula Nod Factor Perception (MtNFP) is a lysin-domain Receptor-Like Kinase (LysM-RLK) that plays a key role in the Rhizobium-legume symbiosis, and is involved in plant immunity. MtNFP also has an inactive kinase domain, suggesting that the protein is involved in different receptor complexes. Using the MtNFP pseudo-kinase domain as a bait in a Yeast two Hybrid screen, we identified M. truncatula SUPPRESSOR OF BIR1 (MtSOBIR1) as a new interactor of MtNFP. We showed that an interaction between the two RLKs can occur in planta and that the kinase domain of MtSOBIR1 is active and can transphosphorylate the pseudo-kinase domain of MtNFP. Like in other plants, our data suggest a positive role of MtSOBIR1 in immunity; MtSOBIR1 could functionally complement an Atsobir1 mutant for defence activation, and a Mtsobir1 mutant was defective in pathogen-induced defence gene expression. We also showed that MtSOBIR1 has a symbiotic role with Mtsobir1 mutants showing a strong symbiotic phenotype in a plant genotype- and rhizobial strain-specific manner. The symbiotic role was apparent both at an early stage of rhizobial infection and in nodules. Together, these data suggest that, like MtNFP, MtSOBIR1 has a dual role, and can control immunity in both pathogenic and beneficial situations, with positive or negative roles, respectively.

plant biology↗

Sustainable reference points for multispecies coral reef fisheries

Sustainably managing fisheries requires regular and reliable evaluation of stock status. However, most multispecies reef fisheries around the globe tend to be data-poor and lack research and monitoring capacity (e.g., long-term fishery data), preventing the estimation of sustainable reference points against which stocks can be assessed. Here, combining fish biomass data for more than 2000 coral reefs with catch estimates from 99 jurisdictions, we estimate site-specific sustainable reference points for coral reef fisheries and use these to assess the status of coral reef fish stocks. We reveal that more than half of jurisdictions with available information have stocks of conservation concern, having failed at least one fisheries sustainability benchmark. We quantify the trade-offs between biodiversity, mean fish length, and ecosystem functions relative to key benchmarks and highlight the ecological benefits of increasing sustainability. Our approach yields multispecies sustainable reference points for coral reef fisheries using environmental conditions, a promising means for enhancing the sustainability of the worlds coral reef fisheries. TeaserA global assessment of the sustainability of multispecies reef fisheries indicates that more than half of jurisdictions have failed at least one of two key sustainability benchmarks.

ecology↗