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Wu, C.

Publications and source records attributed to Wu, C..

At least 163 records · Page 9Linked to original sources

A Large Field-of-View Two- and Three-Photon Microscope for High-Resolution Deep Tissue Imaging

In vivo imaging of large-scale neuron activity plays a pivotal role in unraveling the function of the brains network. Multiphoton microscopy, a powerful tool for deep-tissue imaging, has received sustained interest in advancing its speed, field of view and imaging depth. However, to avoid thermal damage in scattering biological tissue, field of view decreases exponentially as imaging depth increases. We present a suite of innovations to overcome constraints on the field of view in three-photon microscopy and to perform deep imaging that is inaccessible to two-photon microscopy. These innovations enable us to image neuronal activities in a [~]3.5-mm diameter field-of-view at 4 Hz with single-cell resolution and in the deepest cortical layer of mouse brains. We further demonstrate simultaneous large field-of-view two-photon and three-photon imaging, subcortical imaging in the mouse brain, and whole-brain imaging in adult zebrafish. The demonstrated techniques can be integrated into any multiphoton microscope for large-field-of-view and system-level neural circuit research.

neuroscience↗

Mechanisms of ligand recognition and activation of melanin-concentrating hormone receptors

Melanin-concentrating hormone (MCH) is a cyclic neuropeptide that regulates food intake, energy balance, and other physiological functions by stimulating MCHR1 and MCHR2 receptors, both of which are class A G protein-coupled receptors. MCHR1 can couple with multiple G-proteins, including Gi/o, Gq/11, and Gs, while MCHR2 only couple to Gq/11. Here we present cryo-electron microscopy structures of MCH-activated MCHR1 with Gi and MCH-activated MCHR2 with Gq complexes, at the global resolutions of 3.01 [A] and 2.40 [A], respectively. These structures reveal that MCH adopts a consistent cysteine-mediated hairpin loop configuration in both receptors. A central arginine from the LGRVY core motif between the two cysteines of MCH penetrates deeply into the transmembrane pocket, triggering receptor activation. Integrated with mutational and functional insights, our findings elucidate the molecular underpinnings of ligand recognition and MCH receptor activation, offering a structured foundation for targeted drug design.

molecular biology↗

Extracellular domain, hinge, and transmembrane determinants affecting surface CD4 expression of a novel anti-HIV chimeric antigen receptor (CAR) construct

Chimeric antigen receptor (CAR)-T cells have demonstrated clinical potential, but current receptors still need improvements to be successful against chronic HIV infection. In this study, we address some requirements of CAR motifs for strong surface expression of a novel anti-HIV CAR by evaluating important elements in the extracellular, hinge, and transmembrane (TM) domains. When combining a truncated CD4 extracellular domain and CD8 hinge/TM, the novel CAR did not express extracellularly but was detectable intracellularly. By shortening the CD8 hinge, CD4-CAR surface expression was partially recovered and addition of the LYC motif at the end of the CD8 TM fully recovered both intracellular and extracellular CAR expression. Mutation of LYC to TTA or TTC showed severe abrogation of CAR expression by flow cytometry and confocal microscopy. Additionally, we determined that CD4-CAR surface expression could be maximized by the removal of FQKAS motif at the junction of the extracellular domain and the hinge region. CD4-CAR surface expression also resulted in cytotoxic CAR T cell killing of HIV Env+ target cells. In this study, we identified elements that are crucial for optimal CAR surface expression, highlighting the need for structural analysis studies to establish fundamental guidelines of CAR designs.

molecular biology↗

Efficacy of the first bioactive peptide from the pearl

Pearls have high medicinal value. In the present study, we discovered the first bioactive peptide in pearls. The bioactive peptide, KKCHFWPFPW, was a novel angiotensin I-converting enzyme (ACE)-inhibitory peptide derived from the pearl matrix of Pinctada fucata. It was screened and identified using quadrupole time-of-flight mass spectrometry. The molecular weight of the peptide was 1417.5 Da, and its theoretical isoelectric point was 9.31. The half-maximal inhibitory concentration of the peptide was 4.17M, as determined by high-performance liquid chromatography. The Lineweaver-Burk plot showed that this peptide competitively inhibited ACE activity. As the peptide concentration increased, the ACE inhibition rate also increased. The molecular docking was simulated using Maestro 2022-1 Glide software to understand the potential mechanisms underlying the ACE-inhibitory activity of KKCHFWPFPW. These results indicated that the peptide from the P. martensii pearl matrix might be a potential source of antihypertensive peptides.

biochemistry↗

Interplay of RAP2 GTPase and the cytoskeleton in Hippo pathway regulation

The Hippo signaling is instrumental in regulating organ size, regeneration, and carcinogenesis. The cytoskeleton emerges as a primary Hippo signaling modulator. Its structural alterations in response to environmental and intrinsic stimuli control Hippo kinase cascade activity. However, the precise mechanisms underlying the cytoskeleton regulation of Hippo signaling are not fully understood. RAP2 GTPase is known to mediate the mechanoresponses of Hippo signaling via activating the core Hippo kinases LATS1/2 through MAP4Ks and MST1/2. Here we show the pivotal role of the reciprocal regulation between RAP2 GTPase and the cytoskeleton in Hippo signaling. RAP2 deletion undermines the responses of the Hippo pathway to external cues tied to RhoA GTPase inhibition and actin cytoskeleton remodeling, such as energy stress and serum deprivtion. Notably, RhoA inhibitors and actin disruptors fail to activate LATS1/2 effectively in RAP2-deficient cells. RNA sequencing highlighted differential regulation of both actin and microtubule networks by RAP2 gene deletion. Consistently, Taxol, a microtubule-stabilizing agent, was less effective in activating LATS1/2 and inhibiting cell growth in RAP2 and MAP4K4/6/7 knockout cells. In summary, our findings position RAP2 as a central integrator of cytoskeletal signals for Hippo signaling, which offers new avenues for understanding Hippo regulation and therapeutic interventions in Hippo-impaired cancers.

cell biology↗

Large-scale imputation models for multi-ancestry proteome-wide association analysis

Proteome-wide association studies (PWAS) decode the intricate proteomic landscape of biological mechanisms for complex diseases. Traditional PWAS model training relies heavily on individual-level reference proteomes, restricting its capacity to harness the emerging summary-level protein quantitative trait loci (pQTL) data in the public domain. Here we introduced BLISS, a novel framework to train protein imputation models using only pQTL summary statistics. By leveraging extensive pQTL data from the UK Biobank, deCODE, and ARIC studies, we applied BLISS to develop large-scale European PWAS models covering 5,779 unique proteins. We further extended BLISS to integrate with small-scale non-European individual-level datasets, enabling the development of models tailored to Asian and African ancestries. We validated the performance of BLISS models through a systematic multi-ancestry analysis of over 2,500 phenotypes across five major genetic data resources. The newly identified protein-phenotype associations offer valuable insights into their cross-ancestry transferability, the contributions of different proteomic platforms, and the complementary perspectives provided by distinct genomic mapping approaches relevant to drug discovery. The developed models and data resources are freely available at https://www.gcbhub.org/.

genetics↗

Beta-catenin inhibition disrupts the homeostasis of osteogenic/adipogenic differentiation leading to the development of glucocorticoid-induced osteonecrosis of femoral head

Glucocorticoid-induced osteonecrosis of the femoral head (GONFH) is a common refractory joint disease characterized by bone damage and the collapse of femoral head structure. However, the exact pathological mechanisms of GONFH remain unknown. Here, we observed abnormal osteogenesis and adipogenesis associated with decreased {beta}-catenin in the necrotic femoral head of GONFH patients. In vivo and in vitro studies further revealed that glucocorticoid exposure disrupted osteogenic/adipogenic differentiation of bone marrow mesenchymal cells (BMSCs) by inhibiting {beta}-catenin signaling in glucocorticoid-induced GONFH rats. Col2+ lineage largely contributes to BMSCs, and was found an osteogenic commitment in the femoral head through 9 months of lineage trace. Specific deletion of {beta}-catenin in Col2+ cells shifted their commitment from osteoblasts to adipocytes, leading to a full spectrum of disease phenotype of GONFH in adult mice. Overall, we uncover that {beta}-catenin inhibition disrupting the homeostasis of osteogenic/adipogenic differentiation contributes to the development of GONFH, and identify an ideal genetic modified mouse model of GONFH.

pathology↗

Study-Phase Reinstatement: Encoding Spontaneous Thoughts as Memories

Can the brain improve the retrievability of an experience after it has occurred? Systems consolidation theory proposes that item-specific cortical reactivation during post-encoding rest periods facilitates the formation of stable memory representations, a prediction supported by neural evidence in humans and animals. Such reactivation may also occur on shorter time scales, offering a potential account of classic list memory phenomena but lacking in support from neural data. Leveraging the high-temporal specificity of intracranial electroencephalography (iEEG), we investigate spontaneous reactivation of previously experienced items during brief intervals between individual encoding events. Across two large-scale free recall experiments, we show that reactivation during these periods, measured by spectral iEEG similarity, predicts subsequent recall. In a third experiment, we show that the same methodology can identify post-encoding reactivation that correlates with subsequent memory, consistent with previous results. Thus, spontaneous study-phase reinstatement reliably predicts memory behavior, linking psychological accounts to neural mechanisms and providing evidence for rapid consolidation processes during encoding.

neuroscience↗

Spiral NeuroString: High-Density Soft Bioelectronic Fibers for Multimodal Sensing and Stimulation

Bioelectronic fibers hold promise for both research and clinical applications due to their compactness, ease of implantation, and ability to incorporate various functionalities such as sensing and stimulation. However, existing devices suffer from bulkiness, rigidity, limited functionality, and low density of active components. These limitations stem from the difficulty to incorporate many components on one-dimensional (1D) fiber devices due to the incompatibility of conventional microfabrication methods (e.g., photolithography) with curved, thin and long fiber structures. Herein, we introduce a fabrication approach, "spiral transformation'', to convert two-dimensional (2D) films containing microfabricated devices into 1D soft fibers. This approach allows for the creation of high density multimodal soft bioelectronic fibers, termed Spiral NeuroString (S-NeuroString), while enabling precise control over the longitudinal, angular, and radial positioning and distribution of the functional components. We show the utility of S-NeuroString for motility mapping, serotonin sensing, and tissue stimulation within the dynamic and soft gastrointestinal (GI) system, as well as for single-unit recordings in the brain. The described bioelectronic fibers hold great promises for next-generation multifunctional implantable electronics.

bioengineering↗

Use of CRISPR interference for efficient and rapid gene inactivation in Fusobacterium nucleatum

Gene inactivation via creating in-frame deletion mutations in Fusobacterium nucleatum is time-consuming, and most fusobacterial strains are genetically intractable. Addressing these problems, we introduced a riboswitch-based inducible CRISPRi system. This system employs the nuclease-inactive Streptococcus pyogenes Cas9 protein (dCas9), specifically guided to the gene of interest by a constantly expressed single guide RNA (sgRNA). Mechanistically, this dCas9-sgRNA complex serves as an insurmountable roadblock for RNA polymerase, thus repressing the target gene transcription. Leveraging this system, we first examined two non-essential genes, ftsX, and radD, pivotal for fusobacterial cytokinesis and coaggregation. Upon adding the inducer, theophylline, ftsX suppression caused filamentous cell formation akin to chromosomal ftsX deletion, while targeting radD significantly reduced RadD protein levels, abolishing coaggregation. The system was then extended to probe essential genes bamA and ftsZ, vital for outer membrane biogenesis and cell division. Impressively, bamA suppression disrupted membrane integrity and bacterial separation, stalling growth, while ftsZ-targeting yielded elongated cells in broth with compromised agar growth. Further studies on F. nucleatum clinical strain CTI-2 and Fusobacterium periodonticum revealed reduced indole synthesis when targeting tnaA. Moreover, silencing clpB in F. periodonticum decreased ClpB, increasing thermal sensitivity. In summary, our CRISPRi system streamlines gene inactivation across various fusobacterial strains. IMPORTANCEHow can we effectively investigate the gene functions in Fusobacterium nucleatum, given the dual challenges of gene inactivation and the inherent genetic resistance of many strains? Traditional methods have been cumbersome and often inadequate. Addressing this, our work introduces a novel inducible CRISPRi system in which dCas9 expression is controlled at the translation level by a theophylline-responsive riboswitch unit, and sgRNA expression is driven by the robust, constitutive rpsJ promoter. This approach simplifies gene inactivation in the model organism (ATCC 23726) and extends its application to previously considered resistant strains like CTI-2 and Fusobacterium periodontium. With CRISPRis potential, it is a pivotal tool for in-depth genetic studies into fusobacterial pathogenesis, potentially unlocking targeted therapeutic strategies.

microbiology↗

Structure-Activity Relationship Studies of Novel Gut-derived Lantibiotics Against Human Gut Commensals

Recent advances in sequencing techniques unveiled the vast potential of ribosomally synthesized and post-translationally modified peptides (RiPPs) encoded in microbiomes. Class I lantibiotics such as nisin A, widely used as a food preservative, have been investigated for their efficacy in killing pathogens. However, the impact of nisin and nisin-like class I lantibiotics on commensal bacteria residing in the human gut remains unclear. Here, we report six gut-derived class I lantibiotics that are close homologs of nisin, four of which are novel. We applied an improved lantibiotic expression platform to produce and purify these lantibiotics for antimicrobial assays. We determined their minimal inhibitory concentration (MIC) against both Gram-positive human pathogens and gut commensals, and profiled the lantibiotic resistance genes in these pathogens and commensals. SAR studies with variants revealed key regions and residues that impact their antimicrobial properties. Our characterization and SAR studies of nisin-like lantibiotics against both pathogens and human gut commensals could shed light on the future development of lantibiotic-based therapeutics and food preservatives.

bioengineering↗

omicsMIC: a Comprehensive Benchmarking Platform for Robust Comparison of Imputation Methods in Mass Spectrometry-based Omics Data

Mass spectrometry is a powerful and widely used tool for generating proteomics, lipidomics, and metabolomics profiles, which is pivotal for elucidating biological processes and identifying biomarkers. However, missing values in spectrometry-based omics data may pose a critical challenge for the comprehensive identification of biomarkers and elucidation of the biological processes underlying human complex disorders. To alleviate this issue, various imputation methods for mass spectrometry-based omics data have been developed. However, a comprehensive and systematic comparison of these imputation methods is still lacking, and researchers are frequently confronted with a multitude of options without a clear rationale for method selection. To address this pressing need, we developed omicsMIC (mass spectrometrybased omics with Missing values Imputation methods Comparison platform), an interactive platform that provides researchers with a versatile framework to simulate and evaluate the performance of 28 diverse imputation methods. omicsMIC offers a nuanced perspective, acknowledging the inherent heterogeneity in biological data and the unique attributes of each dataset. Our platform empowers researchers to make data-driven decisions in imputation method selection based on real-time visualizations of the outcomes associated with different imputation strategies. The comprehensive benchmarking and versatility of omicsMIC make it a valuable tool for the scientific community engaged in mass spectrometry-based omics research. OmicsMIC is freely available at https://github.com/WQLin8/omicsMIC.

bioinformatics↗

SARS-CoV-2 Omicron infection augments the magnitude and durability of systemic and mucosal immunity in triple-dose CoronaVac recipients

BackgroundThe inactivated whole-virion vaccine, CoronaVac, is one of the most widely used coronavirus disease 2019 (COVID-19) vaccines worldwide. There is a paucity of data indicating the durability of the immune response and the impact of immune imprinting induced by CoronaVac upon Omicron breakthrough infection. MethodsIn this prospective cohort study, 41 recipients of triple-dose CoronaVac and 14 unvaccinated individuals were recruited. We comprehensively profiled adaptive immune parameters in both groups, including spike-specific immunoglobulin (Ig) G and IgA titers, neutralizing activity, B cells, follicular helper T (Tfh) cells, CD4+ and CD8+ T cells, and their memory subpopulations at 12 months after the third booster dose and at 4 weeks and 20 weeks after Omicron BA.5 infection. ResultsTwelve months after the third CoronaVac vaccination, spike-specific antibody and cellular responses were detectable in most vaccinated individuals. BA.5 infection significantly augmented the magnitude, cross-reactivity and durability of serum neutralization activities, Fc-mediated phagocytosis, and nasal spike-specific IgA responses, memory B cells, activated Tfh cells memory CD4+ T cells, and memory CD8+ T cells for both the ancestral strain and Omicron subvariants, compared to unvaccinated individuals. Notably, the increase in BA.5-specific immunity after breakthrough infection was consistently higher than for the ancestral strain, suggesting no evidence of immune imprinting. Immune landscape analyses showed vaccinated individuals have better synchronization of multiple immune components than unvaccinated individuals upon heterologous SARS-CoV-2 infection. ConclusionOur data provides detailed insight into the protective role of inactivated COVID-19 vaccine in shaping humoral and cellular immune responses to heterologous Omicron infection. Trial registrationClinicalTrials.gov NCT05680896 FundingThis study was supported by the National Natural Science Foundation of China (92269118, 92269205), Nanjing Important Science & Technology Specific Projects (2021-11005), Scientific Research Project of Jiangsu Health Commission (M2022013), Clinical Trials from the Affiliated Drum Tower Hospital, Medical School of Nanjing University (2021-LCYJ-PY-9), and Jiangsu graduate practice innovation project (JX22013929).

immunology↗

Bacterial Sphingolipids Exacerbate Colitis by Inhibiting ILC3-derived IL-22 Production.

Commensal bacteria of the Bacteroidetes phylum are the primary producers of sphingolipids in the gut lumen. These lipids serve dual roles as bacterial virulence factors and regulators of the host mucosal immune system, including regulatory T cells and invariant natural killer T cells (iNKT). Sphingolipid composition is significantly altered in fecal samples of patients with inflammatory bowel disease (IBD). However, the specific mechanisms by which bacterial sphingolipids modulate mucosal homeostasis and regulate intestinal inflammation remain unclear. In this study, we investigated the impact of bacterial sphingolipids on intestinal inflammation by mono-colonizing mice with Bacteroides fragilis strains that either express or lack sphingolipids during DSS-induced colitis. We discovered that B. fragilis sphingolipids exacerbate intestinal inflammation. Mice mono-colonized with B. fragilis lacking sphingolipids exhibited less severe DSS-induced colitis. This amelioration of colitis was associated with increased production of interleukin-22 (IL-22) by innate lymphoid cell type 3 (ILC3). Consistent with the inhibitory effect of sphingolipids on IL-22 production, mice colonized with B. fragilis lacking sphingolipids showed enhanced epithelial STAT3 activity, intestinal cell proliferation, and antimicrobial peptide production following DSS treatment compared to those colonized with B. fragilis producing sphingolipids. Additionally, colitis severity in mice colonized with B. fragilis lacking sphingolipids was exacerbated upon IL-22 blockade. Furthermore, our study reveals that bacterial sphingolipids restrict epithelial IL-18 production following DSS treatment and interfere with IL-22 production by a subset of ILC3 cells expressing both the interleukin-18 receptor (IL-18R) and major histocompatibility complex class II (MHC II). These findings indicate that B. fragilis-derived sphingolipids exacerbate mucosal inflammation by impeding epithelial IL-18 expression, resulting in compromised production of IL-22 by ILC3 cells. HighlightsO_LIB. fragilis-derived sphingolipids exacerbate DSS-induced colitis in mono-colonized C57BL/6 mice. C_LIO_LIB. fragilis-derived sphingolipids constrain ILC3-derived IL-22, leading to reduced colonic epithelial cell proliferation and compromised barrier function. C_LIO_LIB. fragilis-derived sphingolipids restrict epithelial NLRC4 inflammasome activation and IL-18 secretion. C_LIO_LIB. fragilis-derived sphingolipids modulate IL-22 production by IL18R+ MHC II+ ILC3s. C_LI

immunology↗

Formin tails act as a switch, inhibiting or enhancing processive actin elongation

Formins are large, multidomain proteins that nucleate new actin filaments and accelerate elongation through a processive interaction with the barbed end of filaments. Their actin assembly activity is generally attributed to their eponymous Formin Homology (FH) 1 and 2 domains; however, evidence is mounting that regions outside of the FH1FH2 stretch also tune actin assembly. Here, we explore the underlying contributions of the tail domain, which spans the sequence between the FH2 domain and the C-terminus of formins. Tails vary in length from [~]0 to >200 residues and contain a number of recognizable motifs. The most well-studied motif is the [~]15 residue long diaphanous autoregulatory domain (DAD). The DAD mediates all or nothing regulation of actin assembly through an intramolecular interaction with the diaphanous inhibitory domain (DID) in the N-terminal half of the protein. Multiple reports demonstrate that the tail can enhance both nucleation and processivity. In this study, we provide a high-resolution view of the alternative splicing encompassing the tail in the Formin Homology Domain-(Fhod) family of formins during development. While four distinct tails are predicted, we found significant levels of only two of these. We characterized the biochemical effects of the different tails. Surprisingly, the two highly expressed Fhod-tails inhibit processive elongation and diminish the nucleation and elongation rates, while a third supports activity. These findings demonstrate a new mechanism of modulating actin assembly by formins and support the model that splice variants are specialized to build distinct actin structures during development.

biochemistry↗

Inhibiting NINJ1-dependent plasma membrane rupture protects against inflammasomeinduced blood coagulation and inflammation

Systemic blood coagulation accompanies inflammation during severe infection like sepsis and COVID. Weve previously established a link between pyroptosis, a vital defense mechanism against infection, and coagulopathy. During pyroptosis, the formation of gasdermin-D (GSDMD) pores on the plasma membrane leads to the release of tissue factor (TF)-positive microvesicles (MVs) that are procoagulant. Mice lacking GSDMD release fewer TF MVs. However, the specific mechanisms leading from activation of GSDMD to MV release remain unclear. Plasma membrane rupture (PMR) in pyroptosis was recently reported to be actively mediated by the transmembrane protein Ninjurin-1 (NINJ1). Here we show that NINJ1 promotes procoagulant MV release during pyroptosis. Haploinsuffciency or glycine inhibition of NINJ1 limited the release of procoagulant MVs and inflammatory cytokines and partially protected against blood coagulation and lethality triggered by bacterial flagellin. Our findings suggest a crucial role for NINJ1-dependent PMR in inflammasome-induced blood coagulation and inflammation.

immunology↗

S-Nitrosylation of CRTC1 in Alzheimer's disease impairs CREB-dependent gene expression induced by neuronal activity

CREB-regulated transcription coactivator 1 (CRTC1) plays an important role in synaptic plasticity, learning and long-term memory formation through regulation of neuronal activity-dependent gene expression, and CRTC1 dysregulation is implicated in Alzheimers disease (AD). Here, we show that increased S-nitrosylation of CRTC1 (forming SNO-CRTC1), as seen in cell-based, animal-based, and human induced pluripotent stem cell (hiPSC)-derived cerebrocortical neuron-based AD models, disrupts its binding with CREB and diminishes the activity-dependent gene expression mediated by the CRTC1/CREB pathway. We identified Cys216 of CRTC1 as the primary target of S-nitrosylation by nitric oxide (NO)-related species. Using CRISPR/Cas9 techniques, we mutated Cys216 to Ala in hiPSC-derived cerebrocortical neurons bearing one allele of the APPSwe mutation (AD-hiPSC neurons). Introduction of this non-nitrosylatable CRTC1 construct rescued defects in AD-hiPSC neurons, including decreased neurite length and increased neuronal cell death. Additionally, expression of non-nitrosylatable CRTC1 in vivo in the hippocampus rescued synaptic plasticity in the form of long-term potentiation (LTP) in 5XFAD mice. Taken together, these results demonstrate that formation of SNO-CRTC1 contributes to the pathogenesis of AD by attenuating the neuronal activity-dependent CREB transcriptional pathway, and suggests a novel therapeutic target for AD.

neuroscience↗

Disordered C-terminal domain drives spatiotemporal confinement of RNAPII to enhance search for chromatin targets

Efficient gene expression requires RNA Polymerase II (RNAPII) to find chromatin targets precisely in space and time. How RNAPII manages this complex diffusive search in 3D nuclear space remains largely unknown. The disordered carboxy-terminal domain (CTD) of RNAPII, which is essential for recruiting transcription-associated proteins, forms phase-separated droplets in vitro, hinting at a potential role in modulating RNAPII dynamics. Here, we use single-molecule tracking and spatiotemporal mapping in living yeast to show that the CTD is required for confining RNAPII diffusion within a subnuclear region enriched for active genes, but without apparent phase separation into condensates. Both Mediator and global chromatin organization are required for sustaining RNAPII confinement. Remarkably, truncating the CTD disrupts RNAPII spatial confinement, prolongs target search, diminishes chromatin binding, impairs pre-initiation complex formation, and reduces transcription bursting. This study illuminates the pivotal role of the CTD in driving spatiotemporal confinement of RNAPII for efficient gene expression.

cell biology↗