scholarly journals Controlled exchange of protein and nucleic acid signals from and between synthetic minimal cells

2022 ◽  
Author(s):  
Joseph M Heili ◽  
Kaitlin Stokes ◽  
Nathaniel J Gaut ◽  
Christopher Deich ◽  
Jose Gomez-Garcia ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Live Cells ◽  
Minimal Cell ◽  
Functional Protein ◽  
Vesicle Membrane ◽  
Synthetic Cell ◽  
Peptide Tags ◽  
Minimal Cells

Synthetic minimal cells are a class of small liposome bioreactors that have some, but not all functions of live cells. Here, we report a critical step towards the development of a bottom-up minimal cell: cellular export of functional protein and RNA products. We used cell penetrating peptide tags to translocate payloads across a synthetic cell vesicle membrane. We demonstrated efficient transport of active enzymes, and transport of nucleic acid payloads by RNA binding proteins. We investigated influence of a concentration gradient alongside other factors on the efficiency of the translocation, and we show a method to increase product accumulation in one location. We demonstrate the use of this technology to engineer molecular communication between different populations of synthetic cells, to exchange protein and nucleic acid signals. The synthetic minimal cell production and export of proteins or nucleic acids allows experimental designs that approach the complexity and relevancy of natural biological systems.

scholarly journals Fluorescence Correlation and Cross-Correlation Spectroscopy Unveil Cytoplasmic mRNP Composition and Dynamics

2020 ◽  
Author(s):  
Àngels Mateu-Regué ◽  
Jan Christiansen ◽  
Christian Hellriegel ◽  
Finn Cilius Nielsen
Keyword(s):  
Life Cycle ◽  
Dynamic Analysis ◽  
Cross Correlation ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Correlation Spectroscopy ◽  
Live Cells ◽  
Macromolecular Complexes ◽  
Fluorescence Correlation ◽  
Macromolecular Composition

ABSTRACTUnderstanding the mRNA life cycle requires analysis of the dynamic macromolecular composition and stoichiometry of mRNPs. Fluorescence correlation and cross-correlation spectroscopy (FCS and FCCS) are appealing technologies to study mRNP complexes because they readily provide information about the molecular composition, stoichiometry, heterogeneity and dynamics of the particles. We developed FCS protocols for analysis of live cells and cellular lysates, and demonstrate the feasibility of analysing common cytoplasmic mRNPs composed of core factor YBX1, IMPs (or IGF2BPs) and their interactions with other RNA binding proteins such as PABPC1, ELAVL2 (HuB), STAU1 and FMRP. FCCS corroborated previously reported RNA dependent interactions between the factors and provided an estimate of the relative overlap between the factors in the mRNPs. In this way FCS and FCCS provide a new and useful approach for the quantitative and dynamic analysis of mRNP macromolecular complexes that may complement current biochemical approaches.

scholarly journals Matrin 3-dependent neurotoxicity is modified by nucleic acid binding and nucleocytoplasmic localization

2018 ◽  
Author(s):  
Ahmed M. Malik ◽  
Roberto A. Miguez ◽  
Xingli Li ◽  
Ye-Shih Ho ◽  
Eva L. Feldman ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Self Assembly ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Nucleic Acid Binding ◽  
Rna Recognition Motifs ◽  
Matrin 3 ◽  
Dna And Rna ◽  
Acid Processing ◽  
Recognition Motifs

ABSTRACTAbnormalities in nucleic acid processing are associated with the development of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Mutations in Matrin 3 (MATR3), a poorly understood DNA- and RNA-binding protein, cause familial ALS/FTD, and MATR3 pathology is a feature of sporadic disease, suggesting that MATR3 dysfunction is integrally linked to ALS pathogenesis. Using a primary neuron model to assess MATR3-mediated toxicity, we noted that neurons were bidirectionally vulnerable to MATR3 levels, with pathogenic MATR3 mutants displaying enhanced toxicity. MATR3’s zinc finger domains partially modulated toxicity, but elimination of its RNA recognition motifs had no effect on neuronal survival, instead facilitating its self-assembly into liquid-like droplets. In contrast to other RNA-binding proteins associated with ALS, cytoplasmic MATR3 redistribution mitigated neurodegeneration, suggesting that nuclear MATR3 mediates toxicity. Our findings offer a foundation for understanding MATR3-related neurodegeneration and how nucleic acid binding functions, localization, and pathogenic mutations drive sporadic and familial disease.

scholarly journals Saccharomyces cerevisiae SSB1 protein and its relationship to nucleolar RNA-binding proteins

1987 ◽  
Vol 7 (8) ◽  
pp. 2947-2955
Author(s):  
A Y Jong ◽  
M W Clark ◽  
M Gilbert ◽  
A Oehm ◽  
J L Campbell
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Nucleic Acid ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Nucleic Acid Binding ◽  
Dna And Rna ◽  
C Terminus

To better define the function of Saccharomyces cerevisiae SSB1, an abundant single-stranded nucleic acid-binding protein, we determined the nucleotide sequence of the SSB1 gene and compared it with those of other proteins of known function. The amino acid sequence contains 293 amino acid residues and has an Mr of 32,853. There are several stretches of sequence characteristic of other eucaryotic single-stranded nucleic acid-binding proteins. At the amino terminus, residues 39 to 54 are highly homologous to a peptide in calf thymus UP1 and UP2 and a human heterogeneous nuclear ribonucleoprotein. Residues 125 to 162 constitute a fivefold tandem repeat of the sequence RGGFRG, the composition of which suggests a nucleic acid-binding site. Near the C terminus, residues 233 to 245 are homologous to several RNA-binding proteins. Of 18 C-terminal residues, 10 are acidic, a characteristic of the procaryotic single-stranded DNA-binding proteins and eucaryotic DNA- and RNA-binding proteins. In addition, examination of the subcellular distribution of SSB1 by immunofluorescence microscopy indicated that SSB1 is a nuclear protein, predominantly located in the nucleolus. Sequence homologies and the nucleolar localization make it likely that SSB1 functions in RNA metabolism in vivo, although an additional role in DNA metabolism cannot be excluded.

scholarly journals Systematic Identification of Protein Phosphorylation-Mediated Interactions

2020 ◽  
Author(s):  
Brendan M. Floyd ◽  
Kevin Drew ◽  
Edward M. Marcotte
Keyword(s):  
Mass Spectrometry ◽  
Protein Phosphorylation ◽  
Protein Interactions ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Specific Protein ◽  
Mass Spectrometry Data ◽  
Size Exclusion ◽  
Functional Protein

ABSTRACTProtein phosphorylation is a key regulatory mechanism involved in nearly every eukaryotic cellular process. Increasingly sensitive mass spectrometry approaches have identified hundreds of thousands of phosphorylation sites but the functions of a vast majority of these sites remain unknown, with fewer than 5% of sites currently assigned a function. To increase our understanding of functional protein phosphorylation we developed an approach for identifying the phosphorylation-dependence of protein assemblies in a systematic manner. A combination of non-specific protein phosphatase treatment, size-exclusion chromatography, and mass spectrometry allowed us to identify changes in protein interactions after the removal of phosphate modifications. With this approach we were able to identify 316 proteins involved in phosphorylation-sensitive interactions. We recovered known phosphorylation-dependent interactors such as the FACT complex and spliceosome, as well as identified novel interactions such as the tripeptidyl peptidase TPP2 and the supraspliceosome component ZRANB2. More generally, we find phosphorylation-dependent interactors to be strongly enriched for RNA-binding proteins, providing new insight into the role of phosphorylation in RNA binding. By searching directly for phosphorylated amino acid residues in mass spectrometry data, we identified the likely regulatory phosphosites on ZRANB2 and FACT complex subunit SSRP1. This study provides both a method and resource for obtaining a better understanding of the role of phosphorylation in native macromolecular assemblies.

scholarly journals Biochemical characterization of INTS3 and C9ORF80, two subunits of hNABP1/2 heterotrimeric complex in nucleic acid binding

2018 ◽  
Vol 475 (1) ◽  
pp. 45-60 ◽  
Author(s):  
Venkatasubramanian Vidhyasagar ◽  
Yujiong He ◽  
Manhong Guo ◽  
Tanu Talwar ◽  
Ravi Shankar Singh ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Rna Binding ◽  
Biochemical Characterization ◽  
Rna Binding Proteins ◽  
Gel Filtration ◽  
Anomalous Behavior ◽  
Random Coil ◽  
Nucleic Acid Binding ◽  
Mobility Shift ◽  
Dna And Rna

Human nucleic acid-binding protein 1 and 2 (hNABP1 and hNABP2, also known as hSSB2 and hSSB1 respectively) form two separate and independent complexes with two identical proteins, integrator complex subunit 3 (INTS3) and C9ORF80. We and other groups have demonstrated that hNABP1 and 2 are single-stranded (ss) DNA- and RNA-binding proteins, and function in DNA repair; however, the function of INTS3 and C9OFR80 remains elusive. In the present study, we purified recombinant proteins INTS3 and C9ORF80 to near homogeneity. Both proteins exist as a monomer in solution; however, C9ORF80 exhibits anomalous behavior on SDS–PAGE and gel filtration because of 48% random coil present in the protein. Using electrophoretic mobility shift assay (EMSA), INTS3 displays higher affinity toward ssRNA than ssDNA, and C9ORF80 binds ssDNA but not ssRNA. Neither of them binds dsDNA, dsRNA, or RNA : DNA hybrid. INTS3 requires minimum of 30 nucleotides, whereas C9OFR80 requires 20 nucleotides for its binding, which increased with the increasing length of ssDNA. Interestingly, our GST pulldown results suggest that the N-terminus of INTS3 is involved in protein–protein interaction, while EMSA implies that the C-terminus is required for nucleic acid binding. Furthermore, we purified the INTS3–hNABP1/2–C9ORF80 heterotrimeric complex. It exhibits weaker binding compared with the individual hNABP1/2; interestingly, the hNABP1 complex prefers ssDNA, whereas hNABP2 complex prefers ssRNA. Using reconstituted heterotrimeric complex from individual proteins, EMSA demonstrates that INTS3, but not C9ORF80, affects the nucleic acid-binding ability of hNABP1 and hNABP2, indicating that INTS3 might regulate hNABP1/2's biological function, while the role of C9ORF80 remains unknown.

scholarly journals Enhanced Immunoprecipitation Techniques for the Identification of RNA Binding Protein Partners: CRD-BP interactions in mammary epithelial cells

2021 ◽  
Author(s):  
Saja A Fakhraldeen ◽  
Scott M Berry ◽  
David J Beebe ◽  
Avtar A Roopra ◽  
Vladimir S Spiegelman ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Epithelial Cells ◽  
Rna Binding ◽  
Mammary Epithelial Cells ◽  
Rna Binding Proteins ◽  
Mammary Epithelial ◽  
Cross Linking ◽  
Chemical Release ◽  
Binding Partners ◽  
Mrna Binding

RNA binding proteins (RBPs) regulate expression of large cohorts of RNA species to affect programmatic changes in cellular phenotypes. In order to describe the function of RBPs within a cell, it is key to identify their mRNA binding partners. This is often done by cross-linking nucleic acids to RBPs, followed by chemical release of the nucleic acid fragments for analysis. However, this methodology is lengthy, involves complex processing leading to extraordinary losses, requires large amounts of starting materials, and is prone to artifacts due to the labile nature of mRNA. To evaluate potential alternative technologies, we tested "exclusion-based" purification of immunoprecipitates (oil-based IFAST™ or air-based SLIDE™), and report here that these methods can efficiently, rapidly and specifically isolate RBP-RNA complexes with minimal handling. The analysis starts with >100x less material than for techniques that include cross-linking. Depending on the specific antibody used, 50-100% of starting protein is retrieved, allowing the assay of endogenous levels of RBP instead of tagged and over-expressed ectopic proteins. Isolated protein and nucleic acid components are purified and analyzed using standard techniques to provide a comprehensive portrait of RBP complexes. Using exclusion-based techniques, we show that the mRNA binding partners for CRD-BP/IMP1/IGF2BP1/ZBP1 in cultured mammary epithelial cells are enriched in mRNAs important for de-toxifying superoxides (glutathione metabolic enzymes) and other mRNAs encoding mitochondrial proteins.

scholarly journals The Disease-Associated Proteins Drosophila Nab2 and Ataxin-2 Interact with Shared RNAs and Coregulate Neuronal Morphology

Genetics ◽  
2021 ◽  
Author(s):  
J Christopher Rounds ◽  
Edwin B Corgiat ◽  
Changtian Ye ◽  
Joseph A Behnke ◽  
Seth M Kelly ◽  
...  
Keyword(s):  
Rna Binding ◽  
Rna Binding Proteins ◽  
Target Selection ◽  
High Specificity ◽  
Neuronal Morphology ◽  
Functional Protein ◽  
Specific Subset ◽  
Drosophila Brain ◽  
Ataxin 2

Abstract Nab2 encodes the Drosophila melanogaster member of a conserved family of zinc finger polyadenosine RNA-binding proteins (RBPs) linked to multiple steps in post-transcriptional regulation. Mutation of the Nab2 human ortholog ZC3H14 gives rise to an autosomal recessive intellectual disability but understanding of Nab2/ZC3H14 function in metazoan nervous systems is limited, in part because no comprehensive identification of metazoan Nab2/ZC3H14-associated RNA transcripts has yet been conducted. Moreover, many Nab2/ZC3H14 functional protein partnerships remain unidentified. Here, we present evidence that Nab2 genetically interacts with Ataxin-2 (Atx2), which encodes a neuronal translational regulator, and that these factors coordinately regulate neuronal morphology, circadian behavior, and adult viability. We then present the first high-throughput identifications of Nab2- and Atx2-associated RNAs in Drosophila brain neurons using RNA immunoprecipitation-sequencing (RIP-Seq). Critically, the RNA interactomes of each RBP overlap, and Nab2 exhibits high specificity in its RNA associations in neurons in vivo, associating with a small fraction of all polyadenylated RNAs. The identities of shared associated transcripts (e.g., drk, me31B, stai) and of transcripts specific to Nab2 or Atx2 (e.g., Arpc2 and tea) promise insight into neuronal functions of, and genetic interactions between, each RBP. Consistent with prior biochemical studies, Nab2-associated neuronal RNAs are overrepresented for internal A-rich motifs, suggesting these sequences may partially mediate Nab2 target selection. These data support a model where Nab2 functionally opposes Atx2 in neurons, demonstrate Nab2 shares associated neuronal RNAs with Atx2, and reveal Drosophila Nab2 associates with a more specific subset of polyadenylated mRNAs than its polyadenosine affinity alone may suggest.

scholarly journals SEA: Simple Enrichment Analysis of motifs

2021 ◽  
Author(s):  
Timothy L. Bailey ◽  
Charles E. Grant
Keyword(s):  
Rna Binding ◽  
Rna Binding Proteins ◽  
Statistical Significance ◽  
Protein Sequences ◽  
Enrichment Analysis ◽  
Sequence Motifs ◽  
Functional Protein ◽  
Protein Motifs ◽  
Motif Enrichment

Motif enrichment algorithms can identify known sequence motifs that are present to a statistically significant degree in DNA, RNA and protein sequences. Databases of such known motifs exist for DNA- and RNA-binding proteins, as well as for many functional protein motifs. The SEA ("Simple Enrichment Analysis") algorithm presented here uses a simple, consistent approach for detecting the enrichment of motifs in DNA, RNA or protein sequences, as well as in sequences using user-defined alphabets. SEA can identify known motifs that are enriched in a single set of input sequences, and can also perform differential motif enrichment analysis when presented with an additional set of control sequences. Using in vivo DNA (ChIP-seq) data as input to SEA, and validating motifs with reference motifs derived from in vitro data, we show that SEA is is faster than three widely-used motif enrichment algorithms (AME, CentriMo and Pscan), while delivering comparable accuracy. We also show that, in contrast to other motif enrichment algorithms, SEA reports accurate estimates of statistical significance. SEA is easy to use via its web server at https://meme-suite.org, and is fully integrated with the widely-used MEME Suite of sequence analysis tools, which can be freely downloaded at the same web site for non-commercial use.

scholarly journals RNA Gelation in Repeat Expansion Disorders

2017 ◽  
Author(s):  
Ankur Jain ◽  
Ronald D. Vale
Keyword(s):  
Rna Binding ◽  
Rna Binding Proteins ◽  
Neuromuscular Disorders ◽  
Cag Repeats ◽  
Live Cells ◽  
Critical Threshold ◽  
Rna Foci ◽  
Repeat Expansions ◽  
Nucleotide Repeats

Expansions of short nucleotide repeats in the protein coding and non-coding regions of >30 genes produce a variety of neurological and neuromuscular disorders including Huntington’s disease (CAG repeats), muscular dystrophy (CTG repeats) and amyotrophic lateral sclerosis (GGGGCC repeats) [1-3]. Expression of expanded repeats alone is sufficient to recapitulate disease pathology in animal models [4-6]. Repeat-containing transcripts accumulate in the nucleus as aberrant “RNA foci” [7-10] and sequester numerous RNA binding proteins [11,12], leading to a disruption of cellular homeostasis [13,14]. Interestingly, RNA foci, as well as the disease symptoms, only manifest at a critical threshold of nucleotide repeats: >30 for CAG/CTG expansions [1] and >7 for the GGGGCC expansion [15]. However, the reason for this characteristic threshold, as well as the molecular mechanism of foci formation, remain unresolved [16]. Here, we show that nucleotide repeat expansions in RNA create templates for multivalent Watson-Crick (CAG/CUG expansions) or Hoogsteen (GGGGCC expansion) base-pairing. These multivalent interactions cause purified RNAs containing repeat expansions to undergo a sol-gel transition and form micron-sized clusters. Reflecting an increase in the valency for intermolecular hybridization, the gelation of purified RNA only occurs above a critical number of trinucleotide or hexanucleotide repeats. These thresholds for in vitro RNA gelation are similar to those associated with manifestation of disease. By visualizing RNA in live cells, we show that nuclear foci form as a result of phase separation of the repeat-containing RNA and that these foci can be dissolved by agents that disrupt RNA gelation in vitro. Analogous to protein aggregation disorders, our results suggest that the sequence-specific gelation of RNAs could be a contributing factor to neurological disease.

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