Molecular dissection of a genome defense pathway in Neurospora crassa

2015 ◽  
Author(s):  
◽  
Erin C. Boone
Keyword(s):  
Neurospora Crassa ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Nuclear Periphery ◽  
Bimolecular Fluorescence Complementation ◽  
Proper Function ◽  
Rnai Pathway ◽  
Binding Motif ◽  
Perinuclear Region ◽  
A Genome

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Meiotic silencing by unpaired DNA (MSUD) is an RNA interference (RNAi) pathway in Neurospora crassa that detects genes without a homologous partner and silences them for the duration of sexual development. In this study, we have further elucidated the function of known MSUD proteins, identified novel proteins that are required for MSUD, and demonstrated the conservation of RNAi-related processes at the nuclear periphery. We began by showing SAD-2 is crucial for the localization of other MSUD proteins in the perinuclear region. These data suggest that SAD-2 works as a scaffold protein and that proper function of MSUD, like other germline RNAi-like systems, is reliant on the presence of silencing proteins in the perinuclear region. An MSUD suppression assay identified two novel MSUD proteins, SAD-Y and SAD-B'. Even though SAD-Y and its homologs contain a conserved putative RNA- binding motif, they have yet to be assigned to a biochemical pathway. Our work here has linked silencing to SAD-Y-like proteins. SAD-Y has been shown to interact with other MSUD factors in both the nucleus and at the nuclear periphery. SAD-B's homolog has been found in the nuage, an epicenter for RNA-binding proteins involved in post-transcriptional regulation for Drosophila germline cells. SAD-B interacts with core MSUD proteins and has an especially intimate association with SMS-2, which requires it for localization. Furthermore, bimolecular fluorescence complementation (BiFC) revealed that SAD-B' interacts with a Golgi retrograde transport protein and an autophagy marker protein, suggesting the importance of the endomembrane system in this RNAi process.

scholarly journals The Sub-Nuclear Localization of RNA-Binding Proteins in KSHV-Infected Cells

Cells ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1958
Author(s):  
Ella Alkalay ◽  
Chen Gam Ze Letova Refael ◽  
Irit Shoval ◽  
Noa Kinor ◽  
Ronit Sarid ◽  
...  
Keyword(s):  
Binding Proteins ◽  
Rna Binding ◽  
Viral Infections ◽  
Rna Binding Proteins ◽  
Nuclear Periphery ◽  
Lytic Cycle ◽  
Splicing Factors ◽  
Nuclear Speckles ◽  
Viral Rnas ◽  
Infected Cells

RNA-binding proteins, particularly splicing factors, localize to sub-nuclear domains termed nuclear speckles. During certain viral infections, as the nucleus fills up with replicating virus compartments, host cell chromatin distribution changes, ending up condensed at the nuclear periphery. In this study we wished to determine the fate of nucleoplasmic RNA-binding proteins and nuclear speckles during the lytic cycle of the Kaposi’s sarcoma associated herpesvirus (KSHV). We found that nuclear speckles became fewer and dramatically larger, localizing at the nuclear periphery, adjacent to the marginalized chromatin. Enlarged nuclear speckles contained splicing factors, whereas other proteins were nucleoplasmically dispersed. Polyadenylated RNA, typically found in nuclear speckles under regular conditions, was also found in foci separated from nuclear speckles in infected cells. Poly(A) foci did not contain lncRNAs known to colocalize with nuclear speckles but contained the poly(A)-binding protein PABPN1. Examination of the localization of spliced viral RNAs revealed that some spliced transcripts could be detected within the nuclear speckles. Since splicing is required for the maturation of certain KSHV transcripts, we suggest that the infected cell does not dismantle nuclear speckles but rearranges their components at the nuclear periphery to possibly serve in splicing and transport of viral RNAs into the cytoplasm.

scholarly journals A Genome-Wide Analysis of the Pentatricopeptide Repeat (PPR) Gene Family and PPR-Derived Markers for Flesh Color in Watermelon (Citrullus lanatus)

Genes ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1125
Author(s):  
Saminathan Subburaj ◽  
Luhua Tu ◽  
Kayoun Lee ◽  
Gwang-Soo Park ◽  
Hyunbae Lee ◽  
...  
Keyword(s):  
Gene Family ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Citrullus Lanatus ◽  
Gene Families ◽  
Nucleotide Polymorphisms ◽  
Pentatricopeptide Repeat ◽  
Flesh Color ◽  
Large Gene ◽  
A Genome

Watermelon (Citrullus lanatus) is an economically important fruit crop grown for consumption of its large edible fruit flesh. Pentatricopeptide-repeat (PPR) encoding genes, one of the large gene families in plants, are important RNA-binding proteins involved in the regulation of plant growth and development by influencing the expression of organellar mRNA transcripts. However, systematic information regarding the PPR gene family in watermelon remains largely unknown. In this comprehensive study, we identified and characterized a total of 422 C. lanatus PPR (ClaPPR) genes in the watermelon genome. Most ClaPPRs were intronless and were mapped across 12 chromosomes. Phylogenetic analysis showed that ClaPPR proteins could be divided into P and PLS subfamilies. Gene duplication analysis suggested that 11 pairs of segmentally duplicated genes existed. In-silico expression pattern analysis demonstrated that ClaPPRs may participate in the regulation of fruit development and ripening processes. Genotyping of 70 lines using 4 single nucleotide polymorphisms (SNPs) from 4 ClaPPRs resulted in match rates of over 0.87 for each validated SNPs in correlation with the unique phenotypes of flesh color, and could be used in differentiating red, yellow, or orange watermelons in breeding programs. Our results provide significant insights for a comprehensive understanding of PPR genes and recommend further studies on their roles in watermelon fruit growth and ripening, which could be utilized for cultivar development of watermelon.

scholarly journals Posttranscriptional regulation of human endogenous retroviruses by RNA-binding motif protein 4, RBM4

2020 ◽  
Vol 117 (42) ◽  
pp. 26520-26530
Author(s):  
Amir K. Foroushani ◽  
Bryan Chim ◽  
Madeline Wong ◽  
Andre Rastegar ◽  
Patrick T. Smith ◽  
...  
Keyword(s):  
Human Genome ◽  
Posttranscriptional Regulation ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Ectopic Expression ◽  
Transcript Level ◽  
Endogenous Retroviruses ◽  
Host Protein ◽  
Binding Motif ◽  
Sequencing Data

The human genome encodes for over 1,500 RNA-binding proteins (RBPs), which coordinate regulatory events on RNA transcripts. Most studies of RBPs have concentrated on their action on host protein-encoding mRNAs, which constitute a minority of the transcriptome. A widely neglected subset of our transcriptome derives from integrated retroviral elements, termed endogenous retroviruses (ERVs), that comprise ∼8% of the human genome. Some ERVs have been shown to be transcribed under physiological and pathological conditions, suggesting that sophisticated regulatory mechanisms to coordinate and prevent their ectopic expression exist. However, it is unknown how broadly RBPs and ERV transcripts directly interact to provide a posttranscriptional layer of regulation. Here, we implemented a computational pipeline to determine the correlation of expression between individual RBPs and ERVs from single-cell or bulk RNA-sequencing data. One of our top candidates for an RBP negatively regulating ERV expression was RNA-binding motif protein 4 (RBM4). We used photoactivatable ribonucleoside-enhanced cross-linking and immunoprecipitation to demonstrate that RBM4 indeed bound ERV transcripts at CGG consensus elements. Loss of RBM4 resulted in an elevated transcript level of bound ERVs of the HERV-K and -H families, as well as increased expression of HERV-K envelope protein. We pinpointed RBM4 regulation of HERV-K to a CGG-containing element that is conserved in the LTRs of HERV-K-10, -K-11, and -K-20, and validated the functionality of this site using reporter assays. In summary, we systematically identified RBPs that may regulate ERV function and demonstrate a role for RBM4 in controlling ERV expression.

scholarly journals Concurrent binding to DNA and RNA facilitates the pluripotency reprogramming activity of Sox2

2020 ◽  
Vol 48 (7) ◽  
pp. 3869-3887 ◽  
Author(s):  
Linlin Hou ◽  
Yuanjie Wei ◽  
Yingying Lin ◽  
Xiwei Wang ◽  
Yiwei Lai ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Target Genes ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
High Mobility ◽  
Binding Motif ◽  
Dna And Rna ◽  
Somatic Cell Reprogramming ◽  
Double Stranded Dna

Abstract Some transcription factors that specifically bind double-stranded DNA appear to also function as RNA-binding proteins. Here, we demonstrate that the transcription factor Sox2 is able to directly bind RNA in vitro as well as in mouse and human cells. Sox2 targets RNA via a 60-amino-acid RNA binding motif (RBM) positioned C-terminally of the DNA binding high mobility group (HMG) box. Sox2 can associate with RNA and DNA simultaneously to form ternary RNA/Sox2/DNA complexes. Deletion of the RBM does not affect selection of target genes but mitigates binding to pluripotency related transcripts, switches exon usage and impairs the reprogramming of somatic cells to a pluripotent state. Our findings designate Sox2 as a multi-functional factor that associates with RNA whilst binding to cognate DNA sequences, suggesting that it may co-transcriptionally regulate RNA metabolism during somatic cell reprogramming.

scholarly journals Functional requirements of AID’s higher order structures and their interaction with RNA-binding proteins

2016 ◽  
Vol 113 (11) ◽  
pp. E1545-E1554 ◽  
Author(s):  
Samiran Mondal ◽  
Nasim A. Begum ◽  
Wenjun Hu ◽  
Tasuku Honjo
Keyword(s):  
Dna Cleavage ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Somatic Hypermutation ◽  
Cytidine Deaminase ◽  
Bimolecular Fluorescence Complementation ◽  
Functional Requirements ◽  
C Terminus ◽  
Gradient Fractionation

Activation-induced cytidine deaminase (AID) is essential for the somatic hypermutation (SHM) and class-switch recombination (CSR) of Ig genes. Although both the N and C termini of AID have unique functions in DNA cleavage and recombination, respectively, during SHM and CSR, their molecular mechanisms are poorly understood. Using a bimolecular fluorescence complementation (BiFC) assay combined with glycerol gradient fractionation, we revealed that the AID C terminus is required for a stable dimer formation. Furthermore, AID monomers and dimers form complexes with distinct heterogeneous nuclear ribonucleoproteins (hnRNPs). AID monomers associate with DNA cleavage cofactor hnRNP K whereas AID dimers associate with recombination cofactors hnRNP L, hnRNP U, and Serpine mRNA-binding protein 1. All of these AID/ribonucleoprotein associations are RNA-dependent. We propose that AID’s structure-specific cofactor complex formations differentially contribute to its DNA-cleavage and recombination functions.

scholarly journals A nuclear localization domain in the hnRNP A1 protein.

1995 ◽  
Vol 129 (3) ◽  
pp. 551-560 ◽  
Author(s):  
H Siomi ◽  
G Dreyfuss
Keyword(s):  
Nuclear Localization ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Binding Motif ◽  
Hnrnp A1 ◽  
Binding Domains ◽  
Rich Domain ◽  
Localization Domain ◽  
Hnrnp Proteins

The heterogeneous nuclear RNP (hnRNP) A1 protein is one of the major pre-mRNA/mRNA binding proteins in eukaryotic cells and one of the most abundant proteins in the nucleus. It is localized to the nucleoplasm and it also shuttles between the nucleus and the cytoplasm. The amino acid sequence of A1 contains two RNP motif RNA-binding domains (RBDs) at the amino terminus and a glycine-rich domain at the carboxyl terminus. This configuration, designated 2x RBD-Gly, is representative of perhaps the largest family of hnRNP proteins. Unlike most nuclear proteins characterized so far, A1 (and most 2x RBD-Gly proteins) does not contain a recognizable nuclear localization signal (NLS). We have found that a segment of ca. 40 amino acids near the carboxyl end of the protein (designated M9) is necessary and sufficient for nuclear localization; attaching this segment to the bacterial protein beta-galactosidase or to pyruvate kinase completely localized these otherwise cytoplasmic proteins to the nucleus. The RBDs and another RNA binding motif found in the glycine-rich domain, the RGG box, are not required for A1 nuclear localization. M9 is a novel type of nuclear localization domain as it does not contain sequences similar to classical basic-type NLS. Interestingly, sequences similar to M9 are found in other nuclear RNA-binding proteins including hnRNP A2.

scholarly journals The key protein of endosomal mRNP transport Rrm4 binds translational landmark sites of cargo mRNAs

2018 ◽  
Author(s):  
Lilli Olgeiser ◽  
Carl Haag ◽  
Susan Boerner ◽  
Jernej Ule ◽  
Anke Busch ◽  
...  
Keyword(s):  
Rna Binding ◽  
Rna Binding Proteins ◽  
Specific Binding ◽  
Hyphal Growth ◽  
Binding Motif ◽  
Uv Crosslinking ◽  
Rrm Domain ◽  
Messenger Ribonucleoprotein ◽  
Close Proximity ◽  
Nucleotide Resolution

AbstractRNA-binding proteins (RBPs) determine spatiotemporal gene expression by mediating active transport and local translation of cargo mRNAs. Here, we cast a transcriptome-wide view on the transported mRNAs and cognate RBP binding sites during endosomal messenger ribonucleoprotein (mRNP) transport in Ustilago maydis. Using individual-nucleotide resolution UV crosslinking and immunoprecipitation (iCLIP), we compare the key transport RBP Rrm4 and the newly identified endosomal mRNP component Grp1 that is crucial to coordinate hyphal growth. Both RBPs bind predominantly in the 3’ untranslated region of thousands of shared cargo mRNAs, often in close proximity. Intriguingly, Rrm4 precisely binds at stop codons, which constitute landmark sites of translation, suggesting an intimate connection of mRNA transport and translation. Towards uncovering the code of recognition, we identify UAUG as specific binding motif of Rrm4 that is bound by its third RRM domain. Altogether, we provide first insights into the positional organisation of co-localising RBPs on individual cargo mRNAs.

scholarly journals Interactions of CAF1-NOT complex components from Trypanosoma brucei

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 858 ◽  
Author(s):  
Chaitali Chakraborty ◽  
Abeer Fadda ◽  
Esteban Erben ◽  
Smiths Lueong ◽  
Jörg Hoheisel ◽  
...  
Keyword(s):  
Trypanosoma Brucei ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Animal Cells ◽  
Genome Wide ◽  
A Genome ◽  
Fragment Library ◽  
F Box Protein ◽  
Cyclin F ◽  
Potential Interactions

The CAF1-NOT complex of Trypanosoma brucei, like that of other eukaryotes, contains several NOT proteins (NOT1, NOT3, NOT3/5, NOT10, and NOT11), NOT9/CAF40, and the CAF1 deadenylase, which targets 3' poly(A) tails. Again like other eukaryotes, deadenylation is the first step in the degradation of most trypanosome mRNAs. In animal cells, destruction of unstable mRNAs is accelerated by proteins that bind the RNA in a sequence-specific fashion, and also recruit the CAF1-NOT complex. However, this has not yet been demonstrated for T. brucei. To find interaction partners for the trypanosome NOT complex, we did a genome-wide yeast two-hybrid screen, using a random shotgun protein fragment library, with the subunits CAF40, NOT2, NOT10 and NOT11 as baits. To assess interaction specificity, we compared the results with those from other trypanosome proteins, including the cyclin-F-box protein CFB1. The yeast 2-hybrid screen yielded four putatively interacting proteins for NOT2, eleven for NOT11, but only one for NOT9/CAF40. Both CFB1 and NOT10 had over a hundred potential interactions, indicating a lack of specificity. Nevertheless, a detected interaction between NOT10 and NOT11 is likely to be genuine. We also identified proteins that co-purify with affinity tagged NOT9/CAF40 by mass spectrometry. The co-purifying proteins did not include the 2-hybrid partner, but the results confirmed NOT9/CAF40 association with the CAF1-NOT complex, and suggested interactions with expression-repressing RNA-binding proteins (ZC3H8, ZC3H30, and ZC3H46) and the deadenylase PARN3.

scholarly journals PSDX: A Comprehensive Multi-Omics Association Database of Populus trichocarpa With a Focus on the Secondary Growth in Response to Stresses

2021 ◽  
Vol 12 ◽  
Author(s):  
Huiyuan Wang ◽  
Sheng Liu ◽  
Xiufang Dai ◽  
Yongkang Yang ◽  
Yunjun Luo ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcriptional Regulation ◽  
Transcription Initiation ◽  
High Throughput Sequencing ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Populus Trichocarpa ◽  
Secondary Growth ◽  
A Genome ◽  
Post Transcriptional Regulation

Populus trichocarpa (P. trichocarpa) is a model tree for the investigation of wood formation. In recent years, researchers have generated a large number of high-throughput sequencing data in P. trichocarpa. However, no comprehensive database that provides multi-omics associations for the investigation of secondary growth in response to diverse stresses has been reported. Therefore, we developed a public repository that presents comprehensive measurements of gene expression and post-transcriptional regulation by integrating 144 RNA-Seq, 33 ChIP-seq, and six single-molecule real-time (SMRT) isoform sequencing (Iso-seq) libraries prepared from tissues subjected to different stresses. All the samples from different studies were analyzed to obtain gene expression, co-expression network, and differentially expressed genes (DEG) using unified parameters, which allowed comparison of results from different studies and treatments. In addition to gene expression, we also identified and deposited pre-processed data about alternative splicing (AS), alternative polyadenylation (APA) and alternative transcription initiation (ATI). The post-transcriptional regulation, differential expression, and co-expression network datasets were integrated into a new P. trichocarpa Stem Differentiating Xylem (PSDX) database, which further highlights gene families of RNA-binding proteins and stress-related genes. The PSDX also provides tools for data query, visualization, a genome browser, and the BLAST option for sequence-based query. Much of the data is also available for bulk download. The availability of PSDX contributes to the research related to the secondary growth in response to stresses in P. trichocarpa, which will provide new insights that can be useful for the improvement of stress tolerance in woody plants.

scholarly journals I-KCKT allows dissection-free RNA profiling of adult Drosophila intestinal progenitor cells

2020 ◽  
Author(s):  
Kasun Buddika ◽  
Jingjing Xu ◽  
Ishara S. Ariyapala ◽  
Nicholas S. Sokol
Keyword(s):  
Stem Cell ◽  
Progenitor Cells ◽  
Protein Interactions ◽  
Cell Biology ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Stem Cell Population ◽  
Binding Motif ◽  
Rna Profiling ◽  
Adult Drosophila

AbstractThe adult Drosophila intestinal epithelium is a model system for stem cell biology, but its utility is limited by current biochemical methods that lack cell type resolution. Here, we describe a new proximity-based profiling method that relies upon a GAL4 driver, termed intestinal-kickout-GAL4 (I-KCKT-GAL4), exclusively expressed in intestinal progenitor cells. This method used UV cross-linked whole animal frozen powder as its starting material to immunoprecipitate the RNA cargoes of transgenic epitope-tagged RNA binding proteins driven by I-KCKT-GAL4. When applied to the general mRNA-binder, poly(A)-binding protein, the RNA profile obtained by this method identified 98.8% of transcripts found after progenitor cell sorting, and had low background noise despite being derived from whole animal lysate. We also mapped the targets of the more selective RNA binder, Fragile Mental Retardation Protein, using enhanced CLIP, and report for the first time its binding motif in Drosophila cells. This method will therefore enable the RNA profiling of wildtype and mutant intestinal progenitor cells from intact flies exposed to normal and altered environments, as well as the identification of RNA-protein interactions critical for stem cell function.Summary StatementWe report a dissection-free method to identify proximity-based RNA-protein interactions in an in vivo stem cell population, enabling molecular analysis of these cells at unprecedented speed and resolution.

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