Search NASA⌕ Search

SEARCH · Search NASA

Results for “Gene expression data”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

The FaceBase Consortium: A comprehensive resource for craniofacial researchers

The FaceBase Consortium, funded by the National Institute of Dental and Craniofacial Research, National Institutes of Health, is designed to accelerate understanding of craniofacial developmental biology by generating comprehensive data resources to empower the research community, exploring high-throughput technology, fostering new scientific collaborations among researchers and human/computer interactions, facilitating hypothesis-driven research, and translating science into improved health care to benefit patients. The resources generated by the FaceBase projects include a number of dynamic imaging modalities, genome-wide association studies, software tools for analyzing human facial abnormalities, detailed phenotyping, anatomical and molecular atlases, global and specific gene expression patterns, and transcriptional profiling over the course of embryonic and postnatal development in animal models and humans. The integrated data visualization tools, faceted search infrastructure, and curation provided by the FaceBase Hub offer flexible and intuitive ways to interact with these multidisciplinary data. In parallel, the datasets also offer unique opportunities for new collaborations and training for researchers coming into the field of craniofacial studies. Here we highlight the focus of each spoke project and the integration of datasets contributed by the spokes to facilitate craniofacial research.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Characterization and Regulation of Aquaporin Genes of Sorghum [ Sorghum bicolor (L.) Moench] in Response to Waterlogging Stress

Waterlogging is a significant environmental constraint to crop production, and a better understanding of plant responses is critical for the improvement of crop tolerance to waterlogged soils. Aquaporins (AQPs) are a class of channel-forming proteins that play an important role in water transport in plants. Our study aimed to examine the regulation of AQP genes under waterlogging stress and to characterize the genetic variability of AQP genes in sorghum (Sorghum bicolor). Transcriptional profiling of AQP genes in response to waterlogging stress in nodal root tips and nodal root basal regions of two tolerant and two sensitive sorghum genotypes at 18 and 96 h after waterlogging stress imposition revealed significant gene-specific pattern with regard to genotype, root tissue sample, and time point. For some tissue sample and time point combinations, PIP2-6, PIP2-7, TIP2-2, TIP4-4, and TIP5-1 expression was differentially regulated in tolerant compared to sensitive genotypes. The differential response of these AQP genes suggests that they may play a tissue specific role in mitigating waterlogging stress. Genetic analysis of sorghum revealed that AQP genes were clustered into the same four subfamilies as in maize (Zea mays) and rice (Oryza sativa) and that residues determining the AQP channel specificity were largely conserved across species. Single nucleotide polymorphism (SNP) data from 50 sorghum accessions were used to build an AQP gene-based phylogeny of the haplotypes. Phylogenetic analysis based on single nucleotide polymorphisms of sorghum AQP genes placed the tolerant and sensitive genotypes used for the expression study in distinct groups. Expression analyses suggested that selected AQPs may play a pivotal role in sorghum tolerance to water logging stress. Furthermore experimentation is needed to verify their role and to leverage phylogenetic analyses and AQP expression data to improve water logging tolerance in sorghum.

60 APPLIED LIFE SCIENCES↗
NASA NTRS2000

An early ethylene up-regulated gene encoding a calmodulin-binding protein involved in plant senescence and death

35S-Labeled calmodulin (CaM) was used to screen a tobacco anther cDNA library. A positive clone (NtER1) with high homology to an early ethylene-up-regulated gene (ER66) in tomato, and an Arabidopsis homolog was isolated and characterized. Based on the helical wheel projection, a 25-mer peptide corresponding to the predicted CaM-binding region of NtER1 (amino acids 796-820) was synthesized. The gel-mobility shift assay showed that the peptide formed a stable complex with CaM only in the presence of Ca(2+). CaM binds to NtER1 with high affinity (K(d) approximately 12 nm) in a calcium-dependent manner. Tobacco flowers at different stages of development were treated with ethylene or with 1-methylcyclopropene for 2 h before treating with ethylene. Northern analysis showed that the NtER1 was rapidly induced after 15 min of exposure to ethylene. However, the 2-h 1-methylcyclopropene treatment totally blocked NtER1 expression in flowers at all stages of development, suggesting that NtER1 is an early ethylene-up-regulated gene. The senescing leaves and petals had significantly increased NtER1 induction as compared with young leaves and petals, implying that NtER1 is developmentally regulated and acts as a trigger for senescence and death. This is the first documented evidence for the involvement of Ca(2+)/CaM-mediated signaling in ethylene action.

Non-NASA Center↗
DOE OSTI2022

Molecular Regulatory Mechanisms Drive Emergent Pathogenetic Properties of Neisseria gonorrhoeae

Neisseria gonorrhoeae is the causative agent of the sexually transmitted infection (STI) gonorrhea, with an estimated 87 million annual cases worldwide. N. gonorrhoeae predominantly colonizes the male and female genital tract (FGT). In the FGT, N. gonorrhoeae confronts fluctuating levels of nutrients and oxidative and non-oxidative antimicrobial defenses of the immune system, as well as the resident microbiome. One mechanism utilized by N. gonorrhoeae to adapt to this dynamic FGT niche is to modulate gene expression primarily through DNA-binding transcriptional regulators. Here, we describe the major N. gonorrhoeae transcriptional regulators, genes under their control, and how these regulatory processes lead to pathogenic properties of N. gonorrhoeae during natural infection. We also discuss the current knowledge of the structure, function, and diversity of the FGT microbiome and its influence on gonococcal survival and transcriptional responses orchestrated by its DNA-binding regulators. We conclude with recent multi-omics data and modeling tools and their application to FGT microbiome dynamics. Understanding the strategies utilized by N. gonorrhoeae to regulate gene expression and their impact on the emergent characteristics of this pathogen during infection has the potential to identify new effective strategies to both treat and prevent gonorrhea.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

Discovery, characterization, and application of chromosomal integration sites for stable heterologous gene expression in Rhodotorula toruloides

Rhodotorula toruloides is a non-model, oleaginous yeast uniquely suited to produce acetyl-CoA-derived chemicals. However, the lack of well-characterized genomic integration sites has impeded the metabolic engineering of this organism. Here we report a set of computationally predicted and experimentally validated chromosomal integration sites in R. toruloides. We first implemented an in silico platform by integrating essential gene information and transcriptomic data to identify candidate sites that meet stringent criteria. We then conducted a full experimental characterization of these sites, assessing integration efficiency, gene expression levels, impact on cell growth, and long-term expression stability. Among the identified sites, 12 exhibited integration efficiencies of 50% or higher, making them sufficient for most metabolic engineering applications. Using selected high-efficiency sites, we achieved simultaneous double and triple integrations and efficiently integrated long functional pathways (up to 14.7 kb). Additionally, we developed a new inducible marker recycling system that allows multiple rounds of integration at our characterized sites. Here, we validated this system by performing five sequential rounds of GFP integration and three sequential rounds of MaFAR integration for fatty alcohol production, demonstrating, for the first time, precise gene copy number tuning in R. toruloides. These characterized integration sites should significantly advance metabolic engineering efforts and future genetic tool development in R. toruloides.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Sulfate differentially stimulates but is not respired by diverse anaerobic methanotrophic archaea

Abstract Sulfate-coupled anaerobic oxidation of methane (AOM) is a major methane sink in marine sediments. Multiple lineages of anaerobic methanotrophic archaea (ANME) often coexist in sediments and catalyze this process syntrophically with sulfate-reducing bacteria (SRB), but the potential differences in ANME ecophysiology and mechanisms of syntrophy remain unresolved. A humic acid analog, anthraquinone 2,6-disulfonate (AQDS), could decouple archaeal methanotrophy from bacterial sulfate reduction and serve as the terminal electron acceptor for AOM (AQDS-coupled AOM). Here in sediment microcosm experiments, we examined variations in physiological response between two co-occurring ANME-2 families (ANME-2a and ANME-2c) and tested the hypothesis of sulfate respiration by ANME-2. Sulfate concentrations as low as 100 µM increased AQDS-coupled AOM nearly 2-fold matching the rates of sulfate-coupled AOM. However, the SRB partners remained inactive in microcosms with sulfate and AQDS and neither ANME-2 families respired sulfate, as shown by their cellular sulfur contents and anabolic activities measured using nanoscale secondary ion mass spectrometry. ANME-2a anabolic activity was significantly higher than ANME-2c, suggesting that ANME-2a was primarily responsible for the observed sulfate stimulation of AQDS-coupled AOM. Comparative transcriptomics showed significant upregulation of ANME-2a transcripts linked to multiple ABC transporters and downregulation of central carbon metabolism during AQDS-coupled AOM compared to sulfate-coupled AOM. Surprisingly, genes involved in sulfur anabolism were not differentially expressed during AQDS-coupled AOM with and without sulfate amendment. Collectively, this data indicates that ANME-2 archaea are incapable of respiring sulfate, but sulfate availability differentially stimulates the growth and AOM activity of different ANME lineages.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

Mining Thermophile Photosynthesis Genes: A Synthetic Operon Expressing Chloroflexota Species Reaction Center Genes in Rhodobacter sphaeroides

Photosynthesis is the foundation of the vast majority of life systems, and is therefore the most important bioenergetic process on earth. The greatest diversity of photosynthetic systems is found in microorganisms. However, our understanding of the biophysical and biochemical processes that transduce light into chemical energy is derived from a relatively small subset of proteins from microbes that are amenable to cultivation, in contrast to the huge number of predicted proteins that catalyze the initial photochemical reactions deposited in databases, such as from metagenomics. We describe the use of a Rhodobacter sphaeroides laboratory strain for the expression of heterologous photosynthesis genes to demonstrate the feasibility of mining this resource, focusing on hot spring Chloroflexota gene sequences. Using a synthetic operon of genes, we produced a photochemically active complex of reaction center proteins in our biological system. We also present bioinformatic analyses of anoxygenic type II reaction center sequences from metagenomic samples collected from hot (42–90 °C) springs available through the JGI IMG database, to generate a resource of diverse sequences that are potentially adapted to photosynthesis at such temperatures. These data provide a view into the natural diversity of anoxygenic photosynthesis, through a lens focused on high-temperature environments. The approach we took to express such genes can be applied for potential biotechnology purposes as well as for studies of fundamental catalytic properties of these heretofore inaccessible protein complexes.

Chloroflexota↗
DOE OSTI2025

How volatile isoprenoids improve plant thermotolerance

Volatile isoprenoids mainly include isoprene and monoterpenes, which improve the thermotolerance of the emitting plant by lowering reactive oxygen species (ROS) levels, preserving chloroplast membrane ultrastructure, maintaining photosynthesis and primary metabolism, inducing heat shock proteins, and preserving growth and development. Recent data showed that isoprenoids can act as signaling molecules to improve plant thermotolerance by altering related gene expression through Ca 2+ -mediated signaling pathways. Here, to promote further understanding of isoprenoid-mediated thermotolerance mechanisms, we review current understanding of isoprenoid-induced plant thermotolerance, along with new findings describing the corresponding underlying mechanisms and putative signaling pathways. This information is beneficial for the potential utilization of isoprenoids for enhancing crop tolerance to global warming either by enhancing the emission of isoprenoids or by using isoprenoid-inspired anti-high temperature agents.

Ca2+ signal↗
DOE OSTI2015

Nuclear actin and myosins in adenovirus infection

Adenovirus serotypes have been shown to cause drastic changes in nuclear organization, including the transcription machinery, during infection. This ability of adenovirus to subvert transcription in the host cell facilitates viral replication. Because nuclear actin and nuclear myosin I, myosin V and myosin VI have been implicated as direct regulators of transcription and important factors in the replication of other viruses, we sought to determine how nuclear actin and myosins are involved in adenovirus infection. We first confirmed reorganization of the host's transcription machinery to viral replication centers. We found that nuclear actin also reorganizes to sites of transcription through the intermediate but not the advanced late phase of viral infection. Furthermore, nuclear myosin I localized with nuclear actin and sites of transcription in viral replication centers. Intriguingly, nuclear myosins V and VI, which also reorganized to viral replication centers, exhibited different localization patterns, suggesting specialized roles for these nuclear myosins. Finally, we assessed the role of actin in adenovirus infection and found both cytoplasmic and nuclear actin likely play roles in adenovirus infection and replication. Together our data suggest the involvement of actin and multiple myosins in the nuclear replication and late viral gene expression of adenovirus. - Highlights: • Adenovirus infection causes dramatic changes in the host's transcription machinery. • Nuclear actin is recruited to viral centers during the late phase of infection. • Nuclear myosin I is recruited with nuclear actin to viral replication centers. • Nuclear myosin V and VI are recruited to distinctive regions of viral centers. • Cytoplasmic and nuclear actin polymerization are necessary for Ad replication.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2020

Arabidopsis Dehiscence Zone Polygalacturonase 1 (ADPG1) releases latent defense signals in stems with reduced lignin content

There is considerable interest in engineering plant cell wall components, particularly lignin, to improve forage quality and biomass properties for processing to fuels and bioproducts. However, modifying lignin content and/or composition in transgenic plants through down-regulation of lignin biosynthetic enzymes can induce expression of defense response genes in the absence of biotic or abiotic stress. Arabidopsis thaliana lines with altered lignin through down-regulation of hydroxycinnamoyl CoA:shikimate/quinate hydroxycinnamoyl transferase (HCT) or loss of function of cinnamoyl CoA reductase 1 (CCR1) express a suite of pathogenesis-related (PR) protein genes. The plants also exhibit extensive cell wall remodeling associated with induction of multiple cell wall-degrading enzymes, a process which renders the corresponding biomass a substrate for growth of the cellulolytic thermophile Caldicellulosiruptor bescii lacking a functional pectinase gene cluster. The cell wall remodeling also results in the release of size- and charge-heterogeneous pectic oligosaccharide elicitors of PR gene expression. Genetic analysis shows that both in planta PR gene expression and release of elicitors are the result of ectopic expression in xylem of the gene Arabidopsis Dehiscence Zone Polygalacturonase 1 (ADPG1), which is normally expressed during anther and silique dehiscence. These data highlight the importance of pectin in cell wall integrity and the value of lignin modification as a tool to interrogate the informational content of plant cell walls.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2015

Metabolic Adaptations of Azospirillum brasilense to Oxygen Stress by Cell-to-Cell Clumping and Flocculation

The ability of bacteria to monitor their metabolism and adjust their behavior accordingly is critical to maintain competitiveness in the environment. The motile microaerophilic bacterium Azospirillum brasilense navigates oxygen gradients by aerotaxis in order to locate low oxygen concentrations that can support metabolism. When cells are exposed to elevated levels of oxygen in their surroundings, motile A. brasilense cells implement an alternative response to aerotaxis and form transient clumps by cell-to-cell interactions. Clumping was suggested to represent a behavior protecting motile cells from transiently elevated levels of aeration. Using the proteomics of wild-type and mutant strains affected in the extent of their clumping abilities, we show that cell-to-cell clumping represents a metabolic scavenging strategy that likely prepares the cells for further metabolic stresses. Analysis of mutants affected in carbon or nitrogen metabolism confirmed this assumption. The metabolic changes experienced as clumping progresses prime cells for flocculation, a morphological and metabolic shift of cells triggered under elevated-aeration conditions and nitrogen limitation. The analysis of various mutants during clumping and flocculation characterized an ordered set of changes in cell envelope properties accompanying the metabolic changes. These data also identify clumping and early flocculation to be behaviors compatible with the expression of nitrogen fixation genes, despite the elevated-aeration conditions. Finally, cell-to-cell clumping may thus license diazotrophy to microaerophilic A. brasilense cells under elevated oxygen conditions and prime them for long-term survival via flocculation if metabolic stress persists.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

A high-resolution single-molecule sequencing-based Arabidopsis transcriptome using novel methods of Iso-seq analysis

Accurate and comprehensive annotation of transcript sequences is essential for transcript quantification and differential gene and transcript expression analysis. Single-molecule long-read sequencing technologies provide improved integrity of transcript structures including alternative splicing, and transcription start and polyadenylation sites. However, accuracy is significantly affected by sequencing errors, mRNA degradation, or incomplete cDNA synthesis. We present a new and comprehensive Arabidopsis thaliana Reference Transcript Dataset 3 (AtRTD3). AtRTD3 contains over 169,000 transcripts—twice that of the best current Arabidopsis transcriptome and including over 1500 novel genes. Seventy-eight percent of transcripts are from Iso-seq with accurately defined splice junctions and transcription start and end sites. We develop novel methods to determine splice junctions and transcription start and end sites accurately. Mismatch profiles around splice junctions provide a powerful feature to distinguish correct splice junctions and remove false splice junctions. Stratified approaches identify high-confidence transcription start and end sites and remove fragmentary transcripts due to degradation. AtRTD3 is a major improvement over existing transcriptomes as demonstrated by analysis of an Arabidopsis cold response RNA-seq time-series. AtRTD3 provides higher resolution of transcript expression profiling and identifies cold-induced differential transcription start and polyadenylation site usage. AtRTD3 is the most comprehensive Arabidopsis transcriptome currently. It improves the precision of differential gene and transcript expression, differential alternative splicing, and transcription start/end site usage analysis from RNA-seq data. The novel methods for identifying accurate splice junctions and transcription start/end sites are widely applicable and will improve single-molecule sequencing analysis from any species.

transcription start and end sites↗
DOE OSTI2015

Experimental Systems-Biology Approaches for Clostridia-Based Bioenergy Production

This is the final project report for project "Experimental Systems-Biology Approaches for Clostridia-Based Bioenergy Production" for the funding period of 9/1/12 to 2/28/2015 (three years with a 6-month no-cost extension) OVERVIEW AND PROJECT GOALS The bottleneck of achieving higher rates and titers of toxic metabolites (such as solvents and carboxylic acids that can used as biofuels or biofuel precursors) can be overcome by engineering the stress response system. Thus, understanding and modeling the response of cells to toxic metabolites is a problem of great fundamental and practical significance. In this project, our goal is to dissect at the molecular systems level and build models (conceptual and quantitative) for the stress response of C. acetobutylicum (Cac) to its two toxic metabolites: butanol (BuOH) and butyrate (BA). Transcriptional (RNAseq and microarray based), proteomic and fluxomic data and their analysis are key requirements for this goal. Transcriptional data from mid-exponential cultures of Cac under 4 different levels of BuOH and BA stress was obtained using both microarrays (Papoutsakis group) and deep sequencing (RNAseq; Meyers and Papoutsakis groups). These two sets of data do not only serve to validate each other, but are also used for identification of stress-induced changes in transcript levels, small regulatory RNAs, & in transcriptional start sites. Quantitative proteomic data (Lee group), collected using the iTRAQ technology, are essential for understanding of protein levels and turnover under stress and the various protein-protein interactions that orchestrate the stress response. Metabolic flux changes (Antoniewicz group) of core pathways, which provide important information on the re-allocation of energy and carbon resources under metabolite stress, were examined using 13C-labelled chemicals. Omics data are integrated at different levels and scales. At the metabolic-pathway level, omics data are integrated into a 2nd generation genome-scale model (GSM) (Maranas group). Omics data are also integrated using bioinformatics (Wu and Huang group), whereby regulatory details of gene and protein expression, protein-protein interactions and metabolic flux regulation are incorporated. The PI (Papoutsakis) facilitated project integration through monthly meeting and reports, conference calls, and collaborative manuscript preparation. The five groups collaborated extensively and made a large number of presentations in national and international meetings. It has also published several papers, with several more in the preparation stage. Several PhD, MS and postdoctoral students were trained as part of this collaborative and interdisciplinary project.

09 BIOMASS FUELS↗
NASA NTRS2003

The potato virus X TGBp2 protein association with the endoplasmic reticulum plays a role in but is not sufficient for viral cell-to-cell movement

Potato virus X (PVX) TGBp1, TGBp2, TGBp3, and coat protein are required for virus cell-to-cell movement. Plasmids expressing GFP fused to TGBp2 were bombarded to leaf epidermal cells and GFP:TGBp2 moved cell to cell in Nicotiana benthamiana leaves but not in Nicotiana tabacum leaves. GFP:TGBp2 movement was observed in TGBp1-transgenic N. tabacum, indicating that TGBp2 requires TGBp1 to promote its movement in N. tabacum. In this study, GFP:TGBp2 was detected in a polygonal pattern that resembles the endoplasmic reticulum (ER) network. Amino acid sequence analysis revealed TGBp2 has two putative transmembrane domains. Two mutations separately introduced into the coding sequences encompassing the putative transmembrane domains within the GFP:TGBp2 plasmids and PVX genome, disrupted membrane binding of GFP:TGBp2, inhibited GFP:TGBp2 movement in N. benthamiana and TGBp1-expressing N. tabacum, and inhibited PVX movement. A third mutation, lying outside the transmembrane domains, had no effect on GFP:TGBp2 ER association or movement in N. benthamiana but inhibited GFP:TGBp2 movement in TGBp1-expressing N. tabacum and PVX movement in either Nicotiana species. Thus, ER association of TGBp2 may be required but not be sufficient for virus movement. TGBp2 likely provides an activity for PVX movement beyond ER association.

NASA Discipline Plant Biology↗
DOE OSTI2016

The transcriptional regulator c2h2 accelerates mushroom formation in Agaricus bisporus

The Cys2His2 zinc finger protein gene c2h2 of Schizophyllum commune is involved in mushroom formation. Its inactivation results in a strain that is arrested at the stage of aggregate formation. In this study, the c2h2 orthologue of Agaricus bisporus was over-expressed in this white button mushroom forming basidiomycete using Agrobacterium-mediated transformation. Morphology, cap expansion rate, and total number and biomass of mushrooms were not affected by overexpression of c2h2. However, yield per day of the c2h2 overexpression strains peaked 1 day earlier. These data and expression analysis indicate that C2H2 impacts timing of mushroom formation at an early stage of development, making its encoding gene a target for breeding of commercial mushroom strains.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Metatranscriptomics reveals a shift in microbial community composition and function during summer months in a coastal marine environment

Abstract Temperate coastal marine waters are often thermally stratified from spring through fall but can be dynamic and disrupted by tidal currents and wind‐driven upwelling. These mixing events introduce deeper, cooler water with a higher partial pressure of CO 2 (pCO2) and its associated microbial communities to the surface. Anecdotally, these events impact shellfish hatcheries and farms, warranting improved understanding of changes in composition and activity of marine microbial communities in relation to environmental processes. To characterize both compositional and functional changes associated with abiotic factors, here, we generate a reference metatranscriptome from the Strait of Georgia over representative seasons and analyze metatranscriptomic profiles of the microorganisms present within intake water containing different pCO 2 levels at a shellfish hatchery in British Columbia from June through October. Abiotic factors studied include pH, temperature, alkalinity, aragonite, calcite, and pCO 2 . Community composition changes were observed to occur at broad taxonomic levels and most notably to vary with temperature and pCO 2 . Functional gene expression profiles indicated a strong difference between early (June–July) and late summer (August–October) associated with viral activity. The taxonomic data suggest this could be due to the termination of cyanobacteria and phytoplankton blooms by viral lysis in the late season. Functional analysis indicated fewer differentially expressed transcripts associated with abiotic variables (e.g., pCO 2 ) than with the temporal effect. Microbial composition and activity in these waters vary with both short‐term effects observed alongside abiotic variation and long‐term effects observed across seasons. The analysis of both taxonomy and functional gene expression simultaneously in the same samples by environmental RNA (eRNA metatranscriptomics) provided a more comprehensive view for monitoring water bodies than either would in isolation.

Sutherland, Ben J. G.↗
DOE OSTI2015

The cytoskeletal inhibitors latrunculin A and blebbistatin exert antitumorigenic properties in human hepatocellular carcinoma cells by interfering with intracellular HuR trafficking

The impact of the RNA-binding protein HuR for the post-transcriptional deregulation of tumor-relevant genes is well established. Despite of elevations in HuR expression levels, an increase in cytoplasmic HuR abundance in many cases correlates with a high grade of malignancy. Here, we demonstrated that administration of the actin-depolymerizing macrolide latrunculin A, or blebbistatin, an inhibitor of myosin II ATPase activity, caused a dose- and time-dependent reduction in the high cytoplasmic HuR content of HepG2 and Huh7 hepatocellular carcinoma (HCC) cells. Subcellular fractionation revealed that in addition, both inhibitors strongly attenuated cytoskeletal and membrane-bound HuR abundance and conversely increased the HuR amount in nuclear cell fractions. Concomitant with changes in intracellular HuR localization, both cytoskeletal inhibitors markedly decreased the half-lives of cyclooxygenase-2 (COX-2), cyclin A and cyclin D{sub 1} encoding mRNAs resulting in a significant reduction in their expression levels in HepG2 cells. Importantly, a similar reduction in the expression of these HuR targets was achieved by a RNA interference (RNAi)-mediated knockdown of either HuR or nonmuscle myoin IIA. Using polysomal fractionation, we further demonstrate that the decrease in cytoplasmic HuR by latrunculin A or blebbistatin is accompanied by a marked change in the allocation of HuR and its mRNA cargo from polysomes to ribonucleoprotein (RNP) particles. Functionally, the basal migration and prostaglandin E{sub 2} synthesis are similarly impaired in inhibitor-treated and stable HuR-knockdown HepG2 cells. Our data demonstrate that interfering with the actomyosin-dependent HuR trafficking may comprise a valid therapeutic option for antagonizing pathologic posttranscriptional gene expression by HuR and furthermore emphasize the potential benefit of HuR inhibitory strategies for treatment of HCC. - Highlights: • We tested the effects of latrunculin A and blebbistatin on different HuR activities. • Both cytoskeletal inhibitors disturbed the RNP-polysome HuR allocation in HepG2 cells. • Accordingly, both inhibitors reduced the stability and levels of HuR controlled mRNAs. • Functionally, important HuR-triggered cell functions were impaired by both compounds. • Targeting of HuR trafficking implies a useful approach for novel antitumor therapy.

60 APPLIED LIFE SCIENCES↗