A novel homozygous variant of the PIGK gene caused by paternal disomy in a patient with neurodevelopmental disorder, cerebellar atrophy, and seizures.

Glycosylphosphatidylinositol (GPI)-anchored proteins are located at the cell surface by a covalent attachment between protein and GPI embedded in the plasma membrane. This attachment is catalyzed by GPI transamidase comprising five subunits (PIGK, PIGS, PIGT, PIGU, and GPAA1) in the endoplasmic reticulum. Loss of either subunit of GPI transamidase eliminates cell surface localization of GPI-anchored proteins. In humans, pathogenic variants in either subunit of GPI transamidase cause neurodevelopmental disorders. However, how the loss of GPI-anchored proteins triggers neurodevelopmental defects remains largely unclear. Here, we identified a novel homozygous variant of PIGK, NM_005482:c.481A > G,p. (Met161Val), in a Japanese female patient with neurodevelopmental delay, hypotonia, cerebellar atrophy, febrile seizures, hearing loss, growth impairment, dysmorphic facial features, and brachydactyly. The missense variant was found heterozygous in her father, but not in her mother. Zygosity analysis revealed that the homozygous PIGK variant in the patient was caused by paternal isodisomy. Rescue experiments using PIGK-deficient CHO cells revealed that the p.Met161Val variant of PIGK reduced GPI transamidase activity. Rescue experiments using pigk mutant zebrafish confirmed that the p.Met161Val variant compromised PIGK function in tactile-evoked motor response. We also demonstrated that axonal localization of voltage-gated sodium channels and concomitant generation of action potentials were impaired in pigk-deficient neurons in zebrafish, suggesting a link between GPI-anchored proteins and neuronal defects. Taken together, the missense p.Met161Val variant of PIGK is a novel pathogenic variant that causes the neurodevelopmental disorder.

Like diamonds in the sky? Public perceptions, governance, and information framing of solar geoengineering activities in Mexico, the United Kingdom, and the United States.

Solar geoengineering (also known as solar radiation modification) is garnering more attention (and controversy) among media and policymakers in response to the impacts of climate change. Such debates have become more prominent following the first-ever field trials of stratospheric aerosol injection (SAI) in 2022. How the lay public perceives solar geoengineering remains unclear, however. We use nationally representative samples (N = 3013) in Mexico, United States, and United Kingdom to examine public perceptions of risks and benefits, support, and policy preferences. We also employ an information-framing design that presented individuals with media-style reports on SAI activities differing along three dimensions: location, actor, and scale and purpose. Support for SAI is found to be generally higher in Mexico; perceptions of risks and benefits do not differ between countries. Information about SAI activities has a limited effect. There is evidence that activities conducted by universities receive more support than those by start-up companies.

Actors, legitimacy, and governance challenges facing negative emissions and solar geoengineering technologies.

Institutional theory, behavioral science, sociology and even political science all emphasize the importance of actors in achieving social change. Despite this salience, the actors involved in researching, promoting, or deploying negative emissions and solar geoengineering technologies remain underexplored within the literature. In this study, based on a rigorous sample of semi-structured expert interviews (N = 125), we empirically explore the types of actors and groups associated with both negative emissions and solar geoengineering research and deployment. We investigate emergent knowledge networks and patterns of involvement across space and scale. We examine actors in terms of their support of, opposition to, or ambiguity regarding both types of climate interventions. We reveal incipient and perhaps unforeseen collections of actors; determine which sorts of actors are associated with different technology pathways to comprehend the locations of actor groups and potential patterns of elitism; and assess relative degrees of social acceptance, legitimacy, and governance.

Attention, sentiments and emotions towards emerging climate technologies on Twitter.

Public perception of emerging climate technologies, such as greenhouse gas removal (GGR) and solar radiation management (SRM), will strongly influence their future development and deployment. Studying perceptions of these technologies with traditional survey methods is challenging, because they are largely unknown to the public. Social media data provides a complementary line of evidence by allowing for retrospective analysis of how individuals share their unsolicited opinions. Our large-scale, comparative study of 1.5 million tweets covers 16 GGR and SRM technologies and uses state-of-the-art deep learning models to show how attention, and expressions of sentiment and emotion developed between 2006 and 2021. We find that in recent years, attention has shifted from general geoengineering themes to specific GGR methods. On the other hand, there is little attention to specific SRM technologies and they often coincide with conspiracy narratives. Sentiments and emotions in GGR tweets tend to be more positive, particularly for methods perceived to be natural, but are more negative when framed in the geoengineering context.

Risk-risk governance in a low-carbon future: Exploring institutional, technological, and behavioral tradeoffs in climate geoengineering pathways.

Deliberations are underway to utilize increasingly radical technological options to help address climate change and stabilize the climatic system. Collectively, these options are often referred to as "climate geoengineering." Deployment of such options, however, can create wicked tradeoffs in governance and require adaptive forms of risk management. In this study, we utilize a large and novel set of qualitative expert interview data to more deeply and systematically explore the types of risk-risk tradeoffs that may emerge from the use of 20 different climate geoengineering options, 10 that focus on carbon dioxide or greenhouse gas removal, and 10 that focus on solar radiation management and reflecting sunlight. We specifically consider: What risks does the deployment of these options entail? What types of tradeoffs may emerge through their deployment? We apply a framework that clusters risk-risk tradeoffs into institutional and governance, technological and environmental, and behavioral and temporal dimensions. In doing so, we offer a more complete inventory of risk-risk tradeoffs than those currently available within the respective risk-assessment, energy-systems, and climate-change literatures, and we also point the way toward future research gaps concerning policy, deployment, and risk management.

A Precautionary Assessment of Systemic Projections and Promises From Sunlight Reflection and Carbon Removal Modeling.

Climate change is a paradigmatic example of systemic risk. Recently, proposals for large-scale interventions-carbon dioxide removal (CDR) and solar radiation management (SRM)-have started to redefine climate governance strategies. We describe how evolving modeling practices are trending toward optimized and "best-case" projections-portraying deployment schemes that create both technically slanted and politically sanitized profiles of risk, as well as ideal objectives for CDR and SRM as mitigation-enhancing, time-buying mechanisms for carbon transitions or vulnerable populations. As promises, stylized and hopeful projections may selectively reinforce industry and political activities built around the inertia of the carbon economy. Some evidence suggests this is the emerging case for certain kinds of CDR, where the prospect of future carbon capture substitutes for present mitigation. Either of these implications are systemic: explorations of climatic futures may entrench certain carbon infrastructures. We point out efforts and recommendations to forestall this trend in the implementation of the Paris Agreement, by creating more stakeholder input and strengthening political realism in modeling and other assessments, as well as through policy guardrails.

Determining our climate policy future: expert opinions about negative emissions and solar radiation management pathways.

Negative emissions technologies and solar radiation management techniques could contribute towards climate stability, either by removing carbon dioxide from the atmosphere and storing it permanently or reflecting sunlight away from the atmosphere. Despite concerns about them, such options are increasingly being discussed as crucial complements to traditional climate change mitigation and adaptation. Expectations around negative emissions and solar radiation management and their associated risks and costs shape public and private discussions of how society deals with the climate crisis. In this study, we rely on a large expert survey (N = 74) to critically examine the future potential of both negative emission options (e.g., carbon dioxide removal) and solar radiation management techniques. We designed a survey process that asked a pool of prominent experts questions about (i) the necessity of adopting negative emissions or solar radiation management options, (ii) the desirability of such options when ranked against each other, (iii) estimations of future efficacy in terms of temperature reductions achieved or gigatons of carbon removed, (iv) expectations about future scaling, commercialization, and deployment targets, and (v) potential risks and barriers. Unlike other elicitation processes where experts are more positive or have high expectations about novel options, our results are more critical and cautionary. We find that some options (notably afforestation and reforestation, ecosystem restoration, and soil carbon sequestration) are envisioned frequently as necessary, desirable, feasible, and affordable, with minimal risks and barriers (compared to other options). This contrasts with other options envisaged as unnecessary risky or costly, notably ocean alkalization or fertilization, space-based reflectors, high-altitude sunshades, and albedo management via clouds. Moreover, only the options of afforestation and reforestation and soil carbon sequestration are expected to be widely deployed before 2035, which raise very real concerns about climate and energy policy in the near- to mid-term.

Applied Machine Learning for Prediction of CO2 Adsorption on Biomass Waste-Derived Porous Carbons.

Biomass waste-derived porous carbons (BWDPCs) are a class of complex materials that are widely used in sustainable waste management and carbon capture. However, their diverse textural properties, the presence of various functional groups, and the varied temperatures and pressures to which they are subjected during CO2 adsorption make it challenging to understand the underlying mechanism of CO2 adsorption. Here, we compiled a data set including 527 data points collected from peer-reviewed publications and applied machine learning to systematically map CO2 adsorption as a function of the textural and compositional properties of BWDPCs and adsorption parameters. Various tree-based models were devised, where the gradient boosting decision trees (GBDTs) had the best predictive performance with R2 of 0.98 and 0.84 on the training and test data, respectively. Further, the BWDPCs in the compiled data set were classified into regular porous carbons (RPCs) and heteroatom-doped porous carbons (HDPCs), where again the GBDT model had R2 of 0.99 and 0.98 on the training and 0.86 and 0.79 on the test data for the RPCs and HDPCs, respectively. Feature importance revealed the significance of adsorption parameters, textural properties, and compositional properties in the order of precedence for BWDPC-based CO2 adsorption, effectively guiding the synthesis of porous carbons for CO2 adsorption applications.

RING finger protein 121 facilitates the degradation and membrane localization of voltage-gated sodium channels.

Following their synthesis in the endoplasmic reticulum (ER), voltage-gated sodium channels (NaV) are transported to the membranes of excitable cells, where they often cluster, such as at the axon initial segment of neurons. Although the mechanisms by which NaV channels form and maintain clusters have been extensively examined, the processes that govern their transport and degradation have received less attention. Our entry into the study of these processes began with the isolation of a new allele of the zebrafish mutant alligator, which we found to be caused by mutations in the gene encoding really interesting new gene (RING) finger protein 121 (RNF121), an E3-ubiquitin ligase present in the ER and cis-Golgi compartments. Here we demonstrate that RNF121 facilitates two opposing fates of NaV channels: (i) ubiquitin-mediated proteasome degradation and (ii) membrane localization when coexpressed with auxiliary NaVß subunits. Collectively, these results indicate that RNF121 participates in the quality control of NaV channels during their synthesis and subsequent transport to the membrane.

Public perceptions on carbon removal from focus groups in 22 countries.

Carbon removal is emerging as a pillar of governmental and industry commitments toward achieving Net Zero targets. Drawing from 44 focus groups in 22 countries, we map technical and societal issues that a representative sample of publics raise on five major types of carbon removal (forests, soils, direct air capture, enhanced weathering, and bioenergy with carbon capture and storage), and how these translate to preferences for governance actors, mechanisms, and rationales. We assess gaps and overlaps between a global range of public perceptions and how carbon removal is currently emerging in assessment, innovation, and decision-making. In conclusion, we outline key societal expectations for informing assessment and policy: prioritize public engagement as more than acceptance research; scrutiny and regulation of industry beyond incentivizing innovation; systemic coordination across sectors, levels, and borders; and prioritize underlying causes of climate change and interrelated governance issues.

Public engagement for inclusive and sustainable governance of climate interventions.

The need for public engagement is increasingly evident as discussions intensify around emerging methods for carbon dioxide removal and controversial proposals around solar geoengineering. Based on 44 focus groups in 22 countries across the Global North and Global South (N = 323 participants), this article traces public preferences for a variety of bottom-up and top-down engagement practices ranging from information recipient to broad decision authority. Here, we show that engagement practices need to be responsive to local political cultures and socio-technical environments, while attending to the global dimensions and interconnectedness of the issues at stake. Establishing public engagement as a cornerstone of inclusive and sustainable governance of climate-intervention technologies requires (i) recognizing the diversity of forms and intensities of engaging, (ii) considering national contexts and modes of engagement, (iii) tailoring to technological idiosyncrasies, (iv) adopting power-sensitive practices, (v) accounting for publics' prior experience, (vi) establishing trust and procedural legitimacy and (vii) engaging with tensions and value disagreements.

Public perceptions and support of climate intervention technologies across the Global North and Global South.

Novel, potentially radical climate intervention technologies like carbon dioxide removal and solar geoengineering are attracting attention as the adverse impacts of climate change are increasingly felt. The ability of publics, particularly in the Global South, to participate in discussions about research, policy, and deployment is restricted amidst a lack of familiarity and engagement. Drawing on a large-scale, cross-country exercise of nationally representative surveys (N = 30,284) in 30 countries and 19 languages, this article establishes the first global baseline of public perceptions of climate-intervention technologies. Here, we show that Global South publics are significantly more favorable about potential benefits and express greater support for climate-intervention technologies. The younger age and level of climate urgency and vulnerability of these publics emerge as key explanatory variables, particularly for solar geoengineering. Conversely, Global South publics express greater concern that climate-intervention technologies could undermine climate-mitigation efforts, and that solar geoengineering could promote an unequal distribution of risks between poor and rich countries.

Connexin 39.9 protein is necessary for coordinated activation of slow-twitch muscle and normal behavior in zebrafish.

In many tissues and organs, connexin proteins assemble between neighboring cells to form gap junctions. These gap junctions facilitate direct intercellular communication between adjoining cells, allowing for the transmission of both chemical and electrical signals. In rodents, gap junctions are found in differentiating myoblasts and are important for myogenesis. Although gap junctions were once believed to be absent from differentiated skeletal muscle in mammals, recent studies in teleosts revealed that differentiated muscle does express connexins and is electrically coupled, at least at the larval stage. These findings raised questions regarding the functional significance of gap junctions in differentiated muscle. Our analysis of gap junctions in muscle began with the isolation of a zebrafish motor mutant that displayed weak coiling at day 1 of development, a behavior known to be driven by slow-twitch muscle (slow muscle). We identified a missense mutation in the gene encoding Connexin 39.9. In situ hybridization found connexin 39.9 to be expressed by slow muscle. Paired muscle recordings uncovered that wild-type slow muscles are electrically coupled, whereas mutant slow muscles are not. The further examination of cellular activity revealed aberrant, arrhythmic touch-evoked Ca(2+) transients in mutant slow muscle and a reduction in the number of muscle fibers contracting in response to touch in mutants. These results indicate that Connexin 39.9 facilitates the spreading of neuronal inputs, which is irregular during motor development, beyond the muscle cells and that gap junctions play an essential role in the efficient recruitment of slow muscle fibers.

TRPM7 is required within zebrafish sensory neurons for the activation of touch-evoked escape behaviors.

Mutations in the gene encoding TRPM7 (trpm7), a member of the Transient Receptor Potential (TRP) superfamily of cation channels that possesses an enzymatically active kinase at its C terminus, cause the touch-unresponsive zebrafish mutant touchdown. We identified and characterized a new allele of touchdown, as well as two previously reported alleles, and found that all three alleles harbor mutations that abolish channel activity. Through the selective restoration of TRPM7 expression in sensory neurons, we found that TRPM7's kinase activity and selectivity for divalent cations over monovalent cations were dispensable for touch-evoked activation of escape behaviors in zebrafish. Additional characterization revealed that sensory neurons were present and capable of responding to tactile stimuli in touchdown mutants, indicating that TRPM7 is not required for sensory neuron survival or mechanosensation. Finally, exposure to elevated concentrations of divalent cations was found to restore touch-evoked behaviors in touchdown mutants. Collectively, these findings are consistent with a role for zebrafish TRPM7 within sensory neurons in the modulation of neurotransmitter release at central synapses, similar to that proposed for mammalian TRPM7 at peripheral synapses.

Touch responsiveness in zebrafish requires voltage-gated calcium channel 2.1b.

The molecular and physiological basis of the touch-unresponsive zebrafish mutant fakir has remained elusive. Here we report that the fakir phenotype is caused by a missense mutation in the gene encoding voltage-gated calcium channel 2.1b (CACNA1Ab). Injection of RNA encoding wild-type CaV2.1 restores touch responsiveness in fakir mutants, whereas knockdown of CACNA1Ab via morpholino oligonucleotides recapitulates the fakir mutant phenotype. Fakir mutants display normal current-evoked synaptic communication at the neuromuscular junction but have attenuated touch-evoked activation of motor neurons. NMDA-evoked fictive swimming is not affected by the loss of CaV2.1b, suggesting that this channel is not required for motor pattern generation. These results, coupled with the expression of CACNA1Ab by sensory neurons, suggest that CaV2.1b channel activity is necessary for touch-evoked activation of the locomotor network in zebrafish.

Loss of myotubularin function results in T-tubule disorganization in zebrafish and human myotubular myopathy.

Myotubularin is a lipid phosphatase implicated in endosomal trafficking in vitro, but with an unknown function in vivo. Mutations in myotubularin cause myotubular myopathy, a devastating congenital myopathy with unclear pathogenesis and no current therapies. Myotubular myopathy was the first described of a growing list of conditions caused by mutations in proteins implicated in membrane trafficking. To advance the understanding of myotubularin function and disease pathogenesis, we have created a zebrafish model of myotubular myopathy using morpholino antisense technology. Zebrafish with reduced levels of myotubularin have significantly impaired motor function and obvious histopathologic changes in their muscle. These changes include abnormally shaped and positioned nuclei and myofiber hypotrophy. These findings are consistent with those observed in the human disease. We demonstrate for the first time that myotubularin functions to regulate PI3P levels in a vertebrate in vivo, and that homologous myotubularin-related proteins can functionally compensate for the loss of myotubularin. Finally, we identify abnormalities in the tubulo-reticular network in muscle from myotubularin zebrafish morphants and correlate these changes with abnormalities in T-tubule organization in biopsies from patients with myotubular myopathy. In all, we have generated a new model of myotubular myopathy and employed this model to uncover a novel function for myotubularin and a new pathomechanism for the human disease that may explain the weakness associated with the condition (defective excitation-contraction coupling). In addition, our findings of tubuloreticular abnormalities and defective excitation-contraction coupling mechanistically link myotubular myopathy with several other inherited muscle diseases, most notably those due to ryanodine receptor mutations. Based on our findings, we speculate that congenital myopathies, usually considered entities with similar clinical features but very disparate pathomechanisms, may at their root be disorders of calcium homeostasis.

Examining the synergies and tradeoffs of net-zero climate protection with the Sustainable Development Goals.

This article discusses and illuminates the synergies and jeopardies or tradeoffs that exist between the 17 Sustainable Development Goals (SDGs) and net-zero or future climate protection options such as greenhouse gas removal (GGR) technologies and solar radiation management (SRM) deployment approaches, respectively. Through a large-scale expert-interview exercise (N = 125), the study finds firstly that numerous synergies and tradeoffs exist between GGR, SRM, and the SDGs. More specifically, we reveal that GGR deployment could enhance the attainment of 16 of the 17 SDGs, but this comes with possible tradeoffs with 12 of the SDGs. SRM deployment could not only enhance the attainment of 16 of the 17 SDGs, but also create possible tradeoffs with (a different) 12 SDGs. The findings further support the understanding of the complexity of SRM and GGR proposals and help policymakers and industrial pioneers understand, navigate, and benchmark between geoengineering approaches using sustainable development goals.

touché Is required for touch-evoked generator potentials within vertebrate sensory neurons.

The process by which light touch in vertebrates is transformed into an electrical response in cutaneous mechanosensitive neurons is a largely unresolved question. To address this question we undertook a forward genetic screen in zebrafish (Danio rerio) to identify mutants exhibiting abnormal touch-evoked behaviors, despite the presence of sensory neurons and peripheral neurites. One family, subsequently named touché, was found to harbor a recessive mutation which produced offspring that were unresponsive to light touch, but responded to a variety of other sensory stimuli. The optogenetic activation of motor behaviors by touché mutant sensory neurons expressing channelrhodopsin-2 suggested that the synaptic output of sensory neurons was intact, consistent with a defect in sensory neuron activation. To explore sensory neuron activation we developed an in vivo preparation permitting the precise placement of a combined electrical and tactile stimulating probe upon eGFP-positive peripheral neurites. In wild-type larva electrical and tactile stimulation of peripheral neurites produced action potentials detectable within the cell body. In a subset of these sensory neurons an underlying generator potential could be observed in response to subthreshold tactile stimuli. A closer examination revealed that the amplitude of the generator potential was proportional to the stimulus amplitude. When assayed touché mutant sensory neurons also responded to electrical stimulation of peripheral neurites similar to wild-type larvae, however tactile stimulation of these neurites failed to uncover a subset of sensory neurons possessing generator potentials. These findings suggest that touché is required for generator potentials, and that cutaneous mechanoreceptors with generator potentials are necessary for responsiveness to light touch in zebrafish.

Identification and characterization of novel mouse PDE4D isoforms: molecular cloning, subcellular distribution and detection of isoform-specific intracellular localization signals.

We report here the cloning and characterization of short and supershort mouse PDE4D isoforms. PDE4D is one of the phosphodiesterase enzyme families with multiple promoters and splice variants. PDE4 isoforms present in humans, rats and mice share considerable homology in their catalytic and regulatory domains. In this study, we have identified the novel PDE4D2 variant3 (PDE4D2v3) and PDE4D10 isoforms and the mouse orthologs of PDE4D1, PDE4D2 variant1 (PDE4D2v1), PDE4D2 variant2 (PDE4D2v2) and PDE4D6 isoforms. These isoforms have many different lengths of 5'UTR, signifying the use of different transcription start sites. Our data indicate that many novel PDE4D isoforms exist as a result of alternative mRNA splicing, each isoform having unique N-terminal regions and multiple transcription start sites. Subcellular distribution study showed that the PDE4D1 short isoforms are localized to the nucleus while the supershort isoforms (PDE4D2v1, PDE4D2v2, PDE4D2v3, PDE4D6 and PDE4D10) are restricted to the cytoplasm. Deletion study confirmed that the N-terminus of PDE4D1 is necessary for nuclear targeting. In addition, we showed that the unique N-terminus contains nuclear localization signal sequence. Identifying novel tissue-specific PDE4D isoforms with unique N-terminal regions may aid in the development of selective phosphodiesterase inhibitors.

Characterization of the Zebrafish Glycine Receptor Family Reveals Insights Into Glycine Receptor Structure Function and Stoichiometry.

To study characterization of zebrafish glycine receptors (zGlyRs), we assessed expression and function of five α- and two ß-subunit encoding GlyR in zebrafish. Our qPCR analysis revealed variable expression during development, while in situ hybridizations uncovered expression in the hindbrain and spinal cord; a finding consistent with the reported expression of GlyR subunits in these tissues from other organisms. Electrophysiological recordings using Xenopus oocytes revealed that all five α subunits form homomeric receptors activated by glycine, and inhibited by strychnine and picrotoxin. In contrast, ß subunits only formed functional heteromeric receptors when co-expressed with α subunits. Curiously, the second transmembranes of both ß subunits were found to lack a phenylalanine at the sixth position that is commonly associated with conferring picrotoxin resistance to heteromeric receptors. Consistent with the absence of phenylalanines at the sixth position, heteromeric zGlyRs often lacked significant picrotoxin resistance. Subsequent efforts revealed that resistance to picrotoxin in both zebrafish and human heteromeric GlyRs involves known residues within transmembrane 2, as well as previously unknown residues within transmembrane 3. We also found that a dominant mutation in human GlyRα1 that gives rise to hyperekplexia, and recessive mutations in zebrafish GlyRßb that underlie the bandoneon family of motor mutants, result in reduced receptor function. Lastly, through the use of a concatenated construct we demonstrate that zebrafish heteromeric receptors assemble with a stoichiometry of 3α:2ß. Collectively, our findings have furthered our knowledge regarding the assembly of heteromeric receptors, and the molecular basis of ß subunit-conferred picrotoxin resistance. These results should aid in future investigations of glycinergic signaling in zebrafish and mammals.