scholarly journals Cell Cycle Control by Nuclear Sequestration ofCDC20andCDH1mRNA in Plant Stem Cells

2017 ◽  
Author(s):  
Weibing Yang ◽  
Raymond Wightman ◽  
Elliot M. Meyerowitz
Keyword(s):  
Cell Cycle ◽  
Nuclear Localization ◽  
Cell Cycle Control ◽  
Protein Translation ◽  
Messenger Rnas ◽  
Protein Coding ◽  
Rna Molecules ◽  
Nuclear Envelope Breakdown ◽  
And Function ◽  
Necessary And Sufficient

AbstractIn eukaryotic cells, most RNA molecules are exported into the cytoplasm after being transcribed in the nucleus. Long noncoding RNAs (lncRNAs) have been found to reside and function primarily inside the nucleus, but nuclear localization of protein-coding messenger RNAs (mRNAs) has been considered rare in both animals and plants. Here we show that two mRNAs, transcribed from theCDC20andCCS52B(plant orthologue ofCDH1) genes, are specifically sequestered inside the nucleus during the cell cycle. CDC20 and CDH1 both function as coactivators of the anaphase-promoting complex or cyclosome (APC/C) E3 ligase to trigger cyclin B (C YCB) destruction. In theArabidopsis thalianashoot apical meristem (SAM), we findCDC20andCCS52Bare co-expressed withCYCBsin mitotic cells.CYCBtranscripts can be exported and translated, whereasCDC20andCCS52BmRNAs are strictly confined to the nucleus at prophase and the cognate proteins are not translated until the redistribution of the mRNAs to the cytoplasm after nuclear envelope breakdown (NEBD) at prometaphase. The 5’ untranslated region (UTR) is necessary and sufficient forCDC20mRNA nuclear localization as well as protein translation. Mitotic enrichment ofCDC20andCCS52Btranscripts enables the timely and rapid activation of APC/C, while their nuclear sequestration at prophase appears to protect cyclins from precocious degradation.

scholarly journals Role of Ubiquitin Ligases and the Proteasome in Oncogenesis: Novel Targets for Anticancer Therapies

2013 ◽  
Vol 31 (9) ◽  
pp. 1231-1238 ◽  
Author(s):  
Lindsey N. Micel ◽  
John J. Tentler ◽  
Peter G. Smith ◽  
Gail S. Eckhardt
Keyword(s):  
Cell Cycle ◽  
Anticancer Agents ◽  
Cell Cycle Control ◽  
Ubiquitin Proteasome System ◽  
Cellular Regulation ◽  
Ubiquitin Chain ◽  
Key Enzyme ◽  
Ubiquitin Proteasome ◽  
Enzyme Families ◽  
And Function

The ubiquitin proteasome system (UPS) regulates the ubiquitination, and thus degradation and turnover, of many proteins vital to cellular regulation and function. The UPS comprises a sequential series of enzymatic processes using four key enzyme families: E1 (ubiquitin-activating enzymes), E2 (ubiquitin-carrier proteins), E3 (ubiquitin-protein ligases), and E4 (ubiquitin chain assembly factors). Because the UPS is a crucial regulator of the cell cycle, and abnormal cell-cycle control can lead to oncogenesis, aberrancies within the UPS pathway can result in a malignant cellular phenotype and thus has become an attractive target for novel anticancer agents. This article will provide an overall review of the mechanics of the UPS, describe aberrancies leading to cancer, and give an overview of current drug therapies selectively targeting the UPS.

scholarly journals MicroRNAs: regulators of gene expression and cell differentiation

Blood ◽  
2006 ◽  
Vol 108 (12) ◽  
pp. 3646-3653 ◽  
Author(s):  
Ramesh A. Shivdasani
Keyword(s):  
Gene Expression ◽  
Cell Differentiation ◽  
Protein Translation ◽  
Specific Aspect ◽  
Mirna Biogenesis ◽  
Mirna Regulation ◽  
Protein Coding ◽  
Rna Molecules ◽  
Protein Levels ◽  
Micro Rnas

AbstractThe existence and roles of a class of abundant regulatory RNA molecules have recently come into sharp focus. Micro-RNAs (miRNAs) are small (approximately 22 bases), non–protein-coding RNAs that recognize target sequences of imperfect complementarity in cognate mRNAs and either destabilize them or inhibit protein translation. Although mechanisms of miRNA biogenesis have been elucidated in some detail, there is limited appreciation of their biological functions. Reported examples typically focus on miRNA regulation of a single tissue-restricted transcript, often one encoding a transcription factor, that controls a specific aspect of development, cell differentiation, or physiology. However, computational algorithms predict up to hundreds of putative targets for individual miRNAs, single transcripts may be regulated by multiple miRNAs, and miRNAs may either eliminate target gene expression or serve to finetune transcript and protein levels. Theoretical considerations and early experimental results hence suggest diverse roles for miRNAs as a class. One appealing possibility, that miRNAs eliminate low-level expression of unwanted genes and hence refine unilineage gene expression, may be especially amenable to evaluation in models of hematopoiesis. This review summarizes current understanding of miRNA mechanisms, outlines some of the important outstanding questions, and describes studies that attempt to define miRNA functions in hematopoiesis.

scholarly journals microRNA seedless sites attenuate strong-seed-site-mediated target repression

2019 ◽  
Author(s):  
Xujun Wang ◽  
Jingru Tian ◽  
Peng Cui ◽  
Stephen Mastriano ◽  
Dingyao Zhang ◽  
...  
Keyword(s):  
Protein Translation ◽  
Untranslated Regions ◽  
Seed Region ◽  
Biological Processes ◽  
Messenger Rnas ◽  
Protein Coding ◽  
Attenuation Effect ◽  
Reporter Assays ◽  
Regulate Protein ◽  
Surprising Finding

AbstractMicroRNAs (miRNAs) regulate protein-coding gene expression primarily through cognitive binding sites in the 3’ untranslated regions (3′ UTRs). Seed sites are sequences in messenger RNAs (mRNAs) that form perfect Watson-Crick base-paring with a miRNA’s seed region, which can effectively reduce mRNA abundance and/or repress protein translation. Some seedless sites, which do no form perfect seed-pairing with a miRNA, can also lead to target repression, often with lower efficacy. Here we report the surprising finding that when seedless sites and seed sites are co-present in the same 3’UTR, seedless sites attenuate strong-seed-site-mediated target suppression, independent of 3′ UTR length. This attenuation effect is detectable in >70% of transcriptomic datasets examined, in which specific miRNAs are experimentally increased or decreased. The attenuation effect is confirmed by 3’UTR reporter assays and mediated through base-pairing between miRNA and seedless sites. Furthermore, this seedless-site-based attenuation effect could affect seed sites of the same miRNA or another miRNA, thus partially explaining the variability in target suppression and miRNA-mediated gene upregulation. Our findings reveal an unexpected principle of miRNA-mediated gene regulation, and could impact the understanding of many miRNA-regulated biological processes.

scholarly journals Non-coding RNAs: emerging players in cardiomyocyte proliferation and cardiac regeneration

2020 ◽  
Vol 115 (5) ◽  
Author(s):  
Naisam Abbas ◽  
Filippo Perbellini ◽  
Thomas Thum
Keyword(s):  
Cell Cycle ◽  
Molecular Mechanisms ◽  
Contractile Function ◽  
Cardiac Regeneration ◽  
Therapeutic Interventions ◽  
Circular Rnas ◽  
Cardiomyocyte Proliferation ◽  
Protein Coding ◽  
Rna Molecules ◽  
Non Coding Rnas

Abstract Soon after birth, the regenerative capacity of the mammalian heart is lost, cardiomyocytes withdraw from the cell cycle and demonstrate a minimal proliferation rate. Despite improved treatment and reperfusion strategies, the uncompensated cardiomyocyte loss during injury and disease results in cardiac remodeling and subsequent heart failure. The promising field of regenerative medicine aims to restore both the structure and function of damaged tissue through modulation of cellular processes and regulatory mechanisms involved in cardiac cell cycle arrest to boost cardiomyocyte proliferation. Non-coding RNAs (ncRNAs), such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) are functional RNA molecules with no protein-coding function that have been reported to engage in cardiac regeneration and repair. In this review, we summarize the current understanding of both the biological functions and molecular mechanisms of ncRNAs involved in cardiomyocyte proliferation. Furthermore, we discuss their impact on the structure and contractile function of the heart in health and disease and their application for therapeutic interventions.

scholarly journals Noncanonical Roles of tRNAs: tRNA Fragments and Beyond

2020 ◽  
Vol 54 (1) ◽  
pp. 47-69 ◽  
Author(s):  
Zhangli Su ◽  
Briana Wilson ◽  
Pankaj Kumar ◽  
Anindya Dutta
Keyword(s):  
Sequence Variation ◽  
Protein Translation ◽  
Nutrient Sensing ◽  
Trna Genes ◽  
Biological Processes ◽  
Messenger Rnas ◽  
Regulatory Pathways ◽  
Transfer Rnas ◽  
Rna Molecules

As one of the most abundant and conserved RNA species, transfer RNAs (tRNAs) are well known for their role in reading the codons on messenger RNAs and translating them into proteins. In this review, we discuss the noncanonical functions of tRNAs. These include tRNAs as precursors to novel small RNA molecules derived from tRNAs, also called tRNA-derived fragments, that are abundant across species and have diverse functions in different biological processes, including regulating protein translation, Argonaute-dependent gene silencing, and more. Furthermore, the role of tRNAs in biosynthesis and other regulatory pathways, including nutrient sensing, splicing, transcription, retroelement regulation, immune response, and apoptosis, is reviewed. Genome organization and sequence variation of tRNA genes are also discussed in light of their noncanonical functions. Lastly, we discuss the recent applications of tRNAs in genome editing and microbiome sequencing.

scholarly journals Rev7 dimerization is important for assembly and function of the Rev1/Polζ translesion synthesis complex

2018 ◽  
Vol 115 (35) ◽  
pp. E8191-E8200 ◽  
Author(s):  
Alessandro A. Rizzo ◽  
Faye-Marie Vassel ◽  
Nimrat Chatterjee ◽  
Sanjay D’Souza ◽  
Yunfeng Li ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Cycle Control ◽  
Translesion Synthesis ◽  
Functional Assay ◽  
Binding Motifs ◽  
Dimer Interface ◽  
Dimerization Interface ◽  
And Function

The translesion synthesis (TLS) polymerases Polζ and Rev1 form a complex that enables replication of damaged DNA. The Rev7 subunit of Polζ, which is a multifaceted HORMA (Hop1, Rev7, Mad2) protein with roles in TLS, DNA repair, and cell-cycle control, facilitates assembly of this complex by binding Rev1 and the catalytic subunit of Polζ, Rev3. Rev7 interacts with Rev3 by a mechanism conserved among HORMA proteins, whereby an open-to-closed transition locks the ligand underneath the “safety belt” loop. Dimerization of HORMA proteins promotes binding and release of this ligand, as exemplified by the Rev7 homolog, Mad2. Here, we investigate the dimerization of Rev7 when bound to the two Rev7-binding motifs (RBMs) in Rev3 by combining in vitro analyses of Rev7 structure and interactions with a functional assay in a Rev7−/−cell line. We demonstrate that Rev7 uses the conventional HORMA dimerization interface both to form a homodimer when tethered by the two RBMs in Rev3 and to heterodimerize with other HORMA domains, Mad2 and p31comet. Structurally, the Rev7 dimer can bind only one copy of Rev1, revealing an unexpected Rev1/Polζ architecture. In cells, mutation of the Rev7 dimer interface increases sensitivity to DNA damage. These results provide insights into the structure of the Rev1/Polζ TLS assembly and highlight the function of Rev7 homo- and heterodimerization.

scholarly journals The Reading Frame Surveillance Hypothesis

2016 ◽  
Author(s):  
John T. Gray
Keyword(s):  
Large Subunit ◽  
Protein Translation ◽  
Small Subunit ◽  
Phenotypic Traits ◽  
Biological Processes ◽  
Messenger Rnas ◽  
Protein Coding ◽  
Reading Frame ◽  
Mammalian Sperm ◽  
Translation Mechanism

AbbreviationsRFSReading Frame SurveillanceRdRPRNA-dependent RNA PolymerasefrRNAsFraming RNAsLSULarge SubunitSSUSmall SubunittRFTransfer RNA derived FragmentntnucleotideAbstractAn alternative model for protein translation is presented wherein ribosomes utilize a complementary RNA copy of protein coding sequences to monitor the progress of messenger RNAs during their translation to reduce the frequency of frameshifting errors. The synthesis of this ‘framing RNA’ is postulated to be catalyzed by the small subunit of the ribosome, in the decoding center, by excising and concatemerizing tRNA anticodons bound to each codon of the mRNA template. Various components of the model are supported by previous observations of tRNA mutants that impact ribosomal frameshifting, unique globin-coding RNAs in developing erythroblasts, and the epigenetic, intergenerational transfer of phenotypic traits via mammalian sperm RNA. Confirmation of the proposed translation mechanism is experimentally tractable and might significantly enhance our understanding of several fundamental biological processes.

scholarly journals NOVOMIR: De Novo Prediction of MicroRNA-Coding Regions in a Single Plant-Genome

2010 ◽  
Vol 2010 ◽  
pp. 1-10 ◽  
Author(s):  
Jan-Hendrik Teune ◽  
Gerhard Steger
Keyword(s):  
Noncoding Rna ◽  
De Novo ◽  
Plant Genome ◽  
Messenger Rnas ◽  
Protein Coding ◽  
Rna Molecules ◽  
Coding Regions ◽  
Mirna Genes ◽  
Genomic Scale ◽  
Eukaryotic Genomes

MicroRNAs (miRNA) are small regulatory, noncoding RNA molecules that are transcribed as primary miRNAs (pri-miRNA) from eukaryotic genomes. At least in plants, their regulatory activity is mediated through base-pairing with protein-coding messenger RNAs (mRNA) followed by mRNA degradation or translation repression. We describeNOVOMIR, a program for the identification of miRNA genes in plant genomes. It uses a series of filter steps and a statistical model to discriminate a pre-miRNA from other RNAs and does rely neither on prior knowledge of a miRNA target nor on comparative genomics. The sensitivity and specificity ofNOVOMIR for detection of premiRNAs fromArabidopsis thalianais ~0.83 and ~0.99, respectively. Plant pre-miRNAs are more heterogeneous with respect to size and structure than animal pre-miRNAs. Despite these difficulties,NOVOMIR is well suited to perform searches for pre-miRNAs on a genomic scale.NOVOMIR is written in Perl and relies on two additional, free programs for prediction of RNA secondary structure (RNALFOLD, RNASHAPES).

scholarly journals Noncoding RNAs implication in cardiovascular diseases in the COVID-19 era

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
S. Greco ◽  
A. Madè ◽  
C. Gaetano ◽  
Y. Devaux ◽  
C. Emanueli ◽  
...  
Keyword(s):  
Cardiovascular Diseases ◽  
Cardiovascular System ◽  
Vascular System ◽  
Clinical Care ◽  
Clinical Manifestations ◽  
Noncoding Rnas ◽  
Messenger Rnas ◽  
Protein Coding ◽  
Rna Molecules ◽  
Acute Myocardial Injury

Abstract COronaVIrus Disease 19 (COVID-19) is caused by the infection of the Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2). Although the main clinical manifestations of COVID-19 are respiratory, many patients also display acute myocardial injury and chronic damage to the cardiovascular system. Understanding both direct and indirect damage caused to the heart and the vascular system by SARS-CoV-2 infection is necessary to identify optimal clinical care strategies. The homeostasis of the cardiovascular system requires a tight regulation of the gene expression, which is controlled by multiple types of RNA molecules, including RNA encoding proteins (messenger RNAs) (mRNAs) and those lacking protein-coding potential, the noncoding-RNAs. In the last few years, dysregulation of noncoding-RNAs has emerged as a crucial component in the pathophysiology of virtually all cardiovascular diseases. Here we will discuss the potential role of noncoding RNAs in COVID-19 disease mechanisms and their possible use as biomarkers of clinical use.

scholarly journals Molecular Interaction Map of the Mammalian Cell Cycle Control and DNA Repair Systems

1999 ◽  
Vol 10 (8) ◽  
pp. 2703-2734 ◽  
Author(s):  
Kurt W. Kohn
Keyword(s):  
Cell Cycle ◽  
Molecular Species ◽  
Regulatory Network ◽  
Cell Cycle Control ◽  
Gene Promoter ◽  
Multiprotein Complexes ◽  
Mammalian Cell Cycle ◽  
Pertinent Information ◽  
Interaction Map ◽  
And Function

Eventually to understand the integrated function of the cell cycle regulatory network, we must organize the known interactions in the form of a diagram, map, and/or database. A diagram convention was designed capable of unambiguous representation of networks containing multiprotein complexes, protein modifications, and enzymes that are substrates of other enzymes. To facilitate linkage to a database, each molecular species is symbolically represented only once in each diagram. Molecular species can be located on the map by means of indexed grid coordinates. Each interaction is referenced to an annotation list where pertinent information and references can be found. Parts of the network are grouped into functional subsystems. The map shows how multiprotein complexes could assemble and function at gene promoter sites and at sites of DNA damage. It also portrays the richness of connections between the p53-Mdm2 subsystem and other parts of the network.

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