PAP1 [poly(A) polymerase 1] homozygosity and hyperadenylation are major determinants of increased mRNA stability of CDR1 in azole-resistant clinical isolates of Candida albicans

Microbiology ◽  
2010 ◽  
Vol 156 (2) ◽  
pp. 313-326 ◽  
Author(s):  
Raman Manoharlal ◽  
Jyotsna Gorantala ◽  
Monika Sharma ◽  
Dominique Sanglard ◽  
Rajendra Prasad
Keyword(s):  
Drug Resistance ◽  
Candida Albicans ◽  
Transcriptional Activation ◽  
Mrna Stability ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Dominant Negative ◽  
Clinical Isolates ◽  
Single Type

Using genetically matched azole-susceptible (AS) and azole-resistant (AR) clinical isolates of Candida albicans, we recently demonstrated that CDR1 overexpression in AR isolates is due to its enhanced transcriptional activation and mRNA stability. This study examines the molecular mechanisms underlying enhanced CDR1 mRNA stability in AR isolates. Mapping of the 3′ untranslated region (3′ UTR) of CDR1 revealed that it was rich in adenylate/uridylate (AU) elements, possessed heterogeneous polyadenylation sites, and had putative consensus sequences for RNA-binding proteins. Swapping of heterologous and chimeric lacZ–CDR1 3′ UTR transcriptional reporter fusion constructs did not alter the reporter activity in AS and AR isolates, indicating that cis-acting sequences within the CDR1 3′ UTR itself are not sufficient to confer the observed differential mRNA decay. Interestingly, the poly(A) tail of the CDR1 mRNA of AR isolates was ∼35–50 % hyperadenylated as compared with AS isolates. C. albicans poly(A) polymerase (PAP1), responsible for mRNA adenylation, resides on chromosome 5 in close proximity to the mating type-like (MTL) locus. Two different PAP1 alleles, PAP1-a/PAP1-α, were recovered from AS (MTL-a/MTL-α), while a single type of PAP1 allele (PAP1-α) was recovered from AR isolates (MTL-α/MTL-α). Among the heterozygous deletions of PAP1-a (Δpap1-a/PAP1-α) and PAP1-α (PAP1-a/Δpap1-α), only the former led to relatively enhanced drug resistance, to polyadenylation and to transcript stability of CDR1 in the AS isolate. This suggests a dominant negative role of PAP1-a in CDR1 transcript polyadenylation and stability. Taken together, our study provides the first evidence, to our knowledge, that loss of heterozygosity at the PAP1 locus is linked to hyperadenylation and subsequent increased stability of CDR1 transcripts, thus contributing to enhanced drug resistance.

scholarly journals Transcriptional Activation and Increased mRNA Stability Contribute to Overexpression of CDR1 in Azole-Resistant Candida albicans

2008 ◽  
Vol 52 (4) ◽  
pp. 1481-1492 ◽  
Author(s):  
Raman Manoharlal ◽  
Naseem Akhtar Gaur ◽  
Sneh Lata Panwar ◽  
Joachim Morschhäuser ◽  
Rajendra Prasad
Keyword(s):  
Candida Albicans ◽  
Transcriptional Activation ◽  
Mrna Stability ◽  
Transcription Initiation ◽  
Molecular Mechanisms ◽  
Clinical Isolates ◽  
Coding Region ◽  
Transcriptional Fusion ◽  
Reading Frame ◽  
The Difference

ABSTRACT Many azole-resistant (AR) clinical isolates of Candida albicans display increased expression of the drug transporters CDR1 and CDR2. In this study, we evaluate the molecular mechanisms that contribute to the maintenance of constitutively high CDR1 transcript levels in two matched pairs of azole-susceptible (AS) and AR clinical isolates of C. albicans. To address this, we use reporter constructs of GFP and lacZ fused either to the CDR1 promoter (P CDR1 -GFP/lacZ; transcriptional fusion) or to the CDR1 open reading frame (P CDR1 -CDR1-GFP/lacZ; translational fusion) integrated at the native CDR1 locus. It is observed that expression of the two reporter genes as a transcriptional fusion in the AR isolates is higher than that in matched AS isolates. However, the difference in the reporter activity between the AS and AR isolates is even greater for the translational fusions, indicating that the sequences within the CDR1 coding region also contribute to its increased expression in AR isolates. Further analysis of these observations by transcription run-on assays demonstrated a ∼5- to 7-fold difference in the transcription initiation rates for the AR isolates from those for their respective matched AS isolates. Measurement of mRNA stability showed that the half-life of CDR1 mRNA in the AR isolates was threefold higher than that in the corresponding AS isolates. Our results demonstrate that both increased CDR1 transcription and enhanced CDR1 mRNA stability contribute to the overexpression of CDR1 in AR C. albicans isolates.

scholarly journals Conceptual Advances in Control of Inflammation by the RNA-Binding Protein Tristetraprolin

2021 ◽  
Vol 12 ◽  
Author(s):  
Pavel Kovarik ◽  
Annika Bestehorn ◽  
Jeanne Fesselet
Keyword(s):  
Immune Responses ◽  
Mrna Stability ◽  
Binding Sites ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Rna Degradation ◽  
Decay Rates ◽  
Mrna Destabilization

Regulated changes in mRNA stability are critical drivers of gene expression adaptations to immunological cues. mRNA stability is controlled mainly by RNA-binding proteins (RBPs) which can directly cleave mRNA but more often act as adaptors for the recruitment of the RNA-degradation machinery. One of the most prominent RBPs with regulatory roles in the immune system is tristetraprolin (TTP). TTP targets mainly inflammation-associated mRNAs for degradation and is indispensable for the resolution of inflammation as well as the maintenance of immune homeostasis. Recent advances in the transcriptome-wide knowledge of mRNA expression and decay rates together with TTP binding sites in the target mRNAs revealed important limitations in our understanding of molecular mechanisms of TTP action. Such orthogonal analyses lead to the discovery that TTP binding destabilizes some bound mRNAs but not others in the same cell. Moreover, comparisons of various immune cells indicated that an mRNA can be destabilized by TTP in one cell type while it remains stable in a different cell linage despite the presence of TTP. The action of TTP extends from mRNA destabilization to inhibition of translation in a subset of targets. This article will discuss these unexpected context-dependent functions and their implications for the regulation of immune responses. Attention will be also payed to new insights into the role of TTP in physiology and tissue homeostasis.

scholarly journals Regulation of Translation in the Protozoan Parasite Leishmania

2020 ◽  
Vol 21 (8) ◽  
pp. 2981
Author(s):  
Zemfira N. Karamysheva ◽  
Sneider Alexander Gutierrez Guarnizo ◽  
Andrey L. Karamyshev
Keyword(s):  
Drug Resistance ◽  
Translational Control ◽  
Transcriptional Control ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Protozoan Parasite ◽  
Sand Fly ◽  
Mammalian Host ◽  
Translational Machinery

Leishmaniasis represents a serious health problem worldwide and drug resistance is a growing concern. Leishmania parasites use unusual mechanisms to control their gene expression. In contrast to many other species, they do not have transcriptional regulation. The lack of transcriptional control is mainly compensated by post-transcriptional mechanisms, including tight translational control and regulation of mRNA stability/translatability by RNA-binding proteins. Modulation of translation plays a major role in parasite survival and adaptation to dramatically different environments during change of host; however, our knowledge of fine molecular mechanisms of translation in Leishmania remains limited. Here, we review the current progress in our understanding of how changes in the translational machinery promote parasite differentiation during transmission from a sand fly to a mammalian host, and discuss how translational reprogramming can contribute to the development of drug resistance.

scholarly journals The Role of lncRNAs in Gene Expression Regulation through mRNA Stabilization

2021 ◽  
Vol 7 (1) ◽  
pp. 3
Author(s):  
Maialen Sebastian-delaCruz ◽  
Itziar Gonzalez-Moro ◽  
Ane Olazagoitia-Garmendia ◽  
Ainara Castellanos-Rubio ◽  
Izortze Santin
Keyword(s):  
Gene Expression ◽  
Mrna Stability ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Gene Expression Regulation ◽  
Rna Binding Proteins ◽  
Regulation Of Gene Expression ◽  
Mrna Stabilization ◽  
Living Organisms ◽  
Almost All

mRNA stability influences gene expression and translation in almost all living organisms, and the levels of mRNA molecules in the cell are determined by a balance between production and decay. Maintaining an accurate balance is crucial for the correct function of a wide variety of biological processes and to maintain an appropriate cellular homeostasis. Long non-coding RNAs (lncRNAs) have been shown to participate in the regulation of gene expression through different molecular mechanisms, including mRNA stabilization. In this review we provide an overview on the molecular mechanisms by which lncRNAs modulate mRNA stability and decay. We focus on how lncRNAs interact with RNA binding proteins and microRNAs to avoid mRNA degradation, and also on how lncRNAs modulate epitranscriptomic marks that directly impact on mRNA stability.

scholarly journals The evolution of drug resistance in clinical isolates of Candida albicans

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Christopher B Ford ◽  
Jason M Funt ◽  
Darren Abbey ◽  
Luca Issi ◽  
Candace Guiducci ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Candida Albicans ◽  
Large Scale ◽  
Molecular Mechanisms ◽  
Oral Candidiasis ◽  
Host Adaptation ◽  
Copy Number Variations ◽  
Clinical Isolates ◽  
Ergosterol Biosynthesis ◽  
Healthy Human

Candida albicans is both a member of the healthy human microbiome and a major pathogen in immunocompromised individuals. Infections are typically treated with azole inhibitors of ergosterol biosynthesis often leading to drug resistance. Studies in clinical isolates have implicated multiple mechanisms in resistance, but have focused on large-scale aberrations or candidate genes, and do not comprehensively chart the genetic basis of adaptation. Here, we leveraged next-generation sequencing to analyze 43 isolates from 11 oral candidiasis patients. We detected newly selected mutations, including single-nucleotide polymorphisms (SNPs), copy-number variations and loss-of-heterozygosity (LOH) events. LOH events were commonly associated with acquired resistance, and SNPs in 240 genes may be related to host adaptation. Conversely, most aneuploidies were transient and did not correlate with drug resistance. Our analysis also shows that isolates also varied in adherence, filamentation, and virulence. Our work reveals new molecular mechanisms underlying the evolution of drug resistance and host adaptation.

scholarly journals Controlling Apomixis: Shared Features and Distinct Characteristics of Gene Regulation

Genes ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 329 ◽  
Author(s):  
Anja Schmidt
Keyword(s):  
Transcriptional Activation ◽  
Genetic Basis ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Higher Plants ◽  
Rna Helicases ◽  
Seed Formation ◽  
Molecular Control ◽  
Sexual And Asexual Reproduction

In higher plants, sexual and asexual reproduction through seeds (apomixis) have evolved as alternative strategies. As apomixis leads to the formation of clonal offspring, its great potential for agricultural applications has long been recognized. However, the genetic basis and the molecular control underlying apomixis and its evolutionary origin are to date not fully understood. Both in sexual and apomictic plants, reproduction is tightly controlled by versatile mechanisms regulating gene expression, translation, and protein abundance and activity. Increasing evidence suggests that interrelated pathways including epigenetic regulation, cell-cycle control, hormonal pathways, and signal transduction processes are relevant for apomixis. Additional molecular mechanisms are being identified that involve the activity of DNA- and RNA-binding proteins, such as RNA helicases which are increasingly recognized as important regulators of reproduction. Together with other factors including non-coding RNAs, their association with ribosomes is likely to be relevant for the formation and specification of the apomictic reproductive lineage. Subsequent seed formation appears to involve an interplay of transcriptional activation and repression of developmental programs by epigenetic regulatory mechanisms. In this review, insights into the genetic basis and molecular control of apomixis are presented, also taking into account potential relations to environmental stress, and considering aspects of evolution.

scholarly journals ebv-circRPMS1 Promotes the Progression of EBV-Associated Gastric Carcinoma via Sam68 Complex Dependent Activation of METTL3

2021 ◽  
Author(s):  
Jing-yue Zhang ◽  
Yu Du ◽  
Li-ping Gong ◽  
Yi-ting Shao ◽  
Li-jie Pan ◽  
...  
Keyword(s):  
Gastric Carcinoma ◽  
Transcriptional Activation ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Circular Rnas ◽  
Qrt Pcr

Abstract Background: Emerging studies have showed that circular RNAs (circRNAs) are important regulators for tumorigenesis by modulating malignant behaviors of tumor cells. However, the functions of EBV-encoded circRNAs in EBV-associated gastric carcinoma (EBVaGC) remain poorly understood. Methods: The expression of ebv-circRPMS1 in EBVaGC tissues, xenografts and cell lines were analyzed by BaseScope, qRT-PCR and in situ hybridization (ISH). The effects of ebv-circRPMS1 on gastric carcinoma (GC) cell proliferation, apoptosis, migration and invasion were measured by CCK8, EdU, immunofluorescence (IF), FACS and Transwell assays. qRT-PCR, Western blotting, ChIP, RNA fluorescence in situ hybridization (RNA-FISH), luciferase reporter assays, mass spectrum, RNA immunoprecipitation (RIP), and pulldown assays were used to investigate the molecular mechanisms. Xenograft mouse model was also used to analyze the effect of ebv-circRPMS1 on GC growth and metastasis in vivo.Results: We demonstrated that ebv-circRPMS1 promoted the proliferation, migration, invasion and anti-apoptosis of EBVaGC cells. Mechanistically, ebv-circRPMS1 recruited the Sam68 complex to the promoter of METTL3 and enhanced its transcription. Moreover, overexpression of METTL3 induced transcriptional activation of downstream genes (such as SNAI1, ZMYM1 and SOCS2) via m6A modifications on their mRNAs, which were associated with tumor progression. Besides, RNA binding proteins (RBPs) such as QKI, DHX9 and ILF3, might involve in ebv-circRPMS1 biogenesis. In clinical EBVaGC samples, ebv-circRPMS1 was associated with distant metastasis and poor prognosis. Conclusion: These findings indicated that ebv-circRPMS1 contributed to EBVaGC progression through recruiting the Sam68 complex to activate METTL3 expression and its downstream targets. Ebv-circRPMS1, Sam68 and METTL3 may serve as therapeutic targets for EBVaGC.

scholarly journals Comprehensive landscape and future perspectives of circular RNAs in colorectal cancer

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Fei Long ◽  
Zhi Lin ◽  
Liang Li ◽  
Min Ma ◽  
Zhixing Lu ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Circular Rnas ◽  
Future Perspectives ◽  
Cis Acting ◽  
New Class ◽  
Functional Peptides ◽  
Mirna Sponges

AbstractColorectal cancer (CRC) is a common hereditary tumor that is often fatal. Its pathogenesis involves multiple genes, including circular RNAs (circRNAs). Notably, circRNAs constitute a new class of noncoding RNAs (ncRNAs) with a covalently closed loop structure and have been characterized as stable, conserved molecules that are abundantly expressed in tissue/development-specific patterns in eukaryotes. Based on accumulating evidence, circRNAs are aberrantly expressed in CRC tissues, cells, exosomes, and blood from patients with CRC. Moreover, numerous circRNAs have been identified as either oncogenes or tumor suppressors that mediate tumorigenesis, metastasis and chemoradiation resistance in CRC. Although the regulatory mechanisms of circRNA biogenesis and functions remain fairly elusive, interesting results have been obtained in studies investigating CRC. In particular, the expression of circRNAs in CRC is comprehensively modulated by multiple factors, such as splicing factors, transcription factors, specific enzymes and cis-acting elements. More importantly, circRNAs exert pivotal effects on CRC through various mechanisms, including acting as miRNA sponges or decoys, interacting with RNA binding proteins, and even translating functional peptides. Finally, circRNAs may serve as promising diagnostic and prognostic biomarkers and potential therapeutic targets in the clinical practice of CRC. In this review, we discuss the dysregulation, functions and clinical significance of circRNAs in CRC and further discuss the molecular mechanisms by which circRNAs exert their functions and how their expression is regulated. Based on this review, we hope to reveal the functions of circRNAs in the initiation and progression of cancer and highlight the future perspectives on strategies targeting circRNAs in cancer research.

scholarly journals The RNA-binding protein ELAVL1/HuR is essential for mouse spermatogenesis, acting both at meiotic and postmeiotic stages

2011 ◽  
Vol 22 (16) ◽  
pp. 2875-2885 ◽  
Author(s):  
Mai Nguyen Chi ◽  
Jacques Auriol ◽  
Bernard Jégou ◽  
Dimitris L. Kontoyiannis ◽  
James M.A. Turner ◽  
...  
Keyword(s):  
Germ Cells ◽  
Posttranscriptional Regulation ◽  
Target Gene ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Female Sterility ◽  
Targeted Deletion

Posttranscriptional mechanisms are crucial to regulate spermatogenesis. Accurate protein synthesis during germ cell development relies on RNA binding proteins that control the storage, stability, and translation of mRNAs in a tightly and temporally regulated manner. Here, we focused on the RNA binding protein Embryonic Lethal Abnormal Vision (ELAV) L1/Human antigen R (HuR) known to be a key regulator of posttranscriptional regulation in somatic cells but the function of which during gametogenesis has never been investigated. In this study, we have used conditional loss- and gain-of-function approaches to address this issue in mice. We show that targeted deletion of HuR specifically in germ cells leads to male but not female sterility. Mutant males are azoospermic because of the extensive death of spermatocytes at meiotic divisions and failure of spermatid elongation. The latter defect is also observed upon HuR overexpression. To elucidate further the molecular mechanisms underlying spermatogenesis defects in HuR-deleted and -overexpressing testes, we undertook a target gene approach and discovered that heat shock protein (HSP)A2/HSP70-2, a crucial regulator of spermatogenesis, was down-regulated in both situations. HuR specifically binds hspa2 mRNA and controls its expression at the translational level in germ cells. Our study provides the first genetic evidence of HuR involvement during spermatogenesis and reveals Hspa2 as a target for HuR.

scholarly journals The effective function of circular RNA in colorectal cancer

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Mandana Ameli-Mojarad ◽  
Melika Ameli-Mojarad ◽  
Mahrooyeh Hadizadeh ◽  
Chris Young ◽  
Hosna Babini ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Circular Rna ◽  
Circular Rnas ◽  
Colorectal Tumorigenesis ◽  
Non Coding Rnas ◽  
Mirna Sponges ◽  
Mechanisms Of Development

AbstractColorectal cancer (CRC) is the 3rd most common type of cancer worldwide. Late detection plays role in one-third of annual mortality due to CRC. Therefore, it is essential to find a precise and optimal diagnostic and prognostic biomarker for the identification and treatment of colorectal tumorigenesis. Covalently closed, circular RNAs (circRNAs) are a class of non-coding RNAs, which can have the same function as microRNA (miRNA) sponges, as regulators of splicing and transcription, and as interactors with RNA-binding proteins (RBPs). Therefore, circRNAs have been investigated as specific targets for diagnostic and prognostic detection of CRC. These non-coding RNAs are also linked to metastasis, proliferation, differentiation, migration, angiogenesis, apoptosis, and drug resistance, illustrating the importance of understanding their involvement in the molecular mechanisms of development and progression of CRC. In this review, we present a detailed summary of recent findings relating to the dysregulation of circRNAs and their potential role in CRC.

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