Alternative polyadenylation and RNA-binding proteins

Our understanding of the extent of microRNA-based gene regulation has expanded in an impressive pace over the past decade. Now, we are beginning to better appreciate the role of 3′-UTR (untranslated region) cis-elements which harbor not only microRNA but also RNA-binding protein (RBP) binding sites that have significant effect on the stability and translational rate of mRNAs. To add further complexity, alternative polyadenylation (APA) emerges as a widespread mechanism to regulate gene expression by producing shorter or longer mRNA isoforms that differ in the length of their 3′-UTRs or even coding sequences. Resulting shorter mRNA isoforms generally lack cis-elements where trans-acting factors bind, and hence are differentially regulated compared with the longer isoforms. This review focuses on the RBPs involved in APA regulation and their action mechanisms on APA-generated isoforms. A better understanding of the complex interactions between APA and RBPs is promising for mechanistic and clinical implications including biomarker discovery and new therapeutic approaches.

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A comprehensive analysis of 3′ end sequencing data sets reveals novel polyadenylation signals and the repressive role of heterogenous ribonucleoprotein C on cleavage and polyadenylation

10.1101/033001 ◽

2015 ◽

Author(s):

Andreas J Gruber ◽

Ralf Schmidt ◽

Andreas R Gruber ◽

Georges Martin ◽

Souvik Ghosh ◽

...

Keyword(s):

Rna Binding ◽

Rna Binding Proteins ◽

Protein Localization ◽

Alternative Polyadenylation ◽

General Mechanism ◽

Data Sets ◽

Sequencing Data ◽

A Genome ◽

The Stability

Alternative polyadenylation (APA) is a general mechanism of transcript diversification in mammals, which has been recently linked to proliferative states and cancer. Different 3′ untranslated region (3′ UTR) isoforms interact with different RNA binding proteins (RBPs), which modify the stability, translation, and subcellular localization of the corresponding transcripts. Although the heterogeneity of pre-mRNA 3′ end processing has been established with high-throughput approaches, the mechanisms that underlie systematic changes in 3′ UTR lengths remain to be characterized. Through a uniform analysis of a large number of 3′ end sequencing data sets we have uncovered 18 signals, 6 of which novel, whose positioning with respect to pre-mRNA cleavage sites indicates a role in pre-mRNA 3′ end processing in both mouse and human. With 3′ end sequencing we have demonstrated that the heterogeneous ribonucleoprotein C (HNRNPC), which binds the poly(U) motif whose frequency also peaks in the vicinity of polyadenylation (poly(A)) sites, has a genome-wide effect on poly(A) site usage. HNRNPC-regulated 3′ UTRs are enriched in ELAV-like RNA binding protein 1 (ELAVL1) binding sites and include those of the CD47 molecule (CD47) gene, which participate in the recently discovered mechanism of 3′ UTR-dependent protein localization (UDPL). Our study thus establishes an up-to-date, high-confidence catalog of 3′ end processing sites and poly(A) signals and it uncovers an important role of HNRNPC in regulating 3′ end processing. It further suggests that U-rich elements mediate interactions with multiple RBPs that regulate different stages in a transcript’s life cycle.

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Regulation, diversity and function of MECP2 exon and 3′UTR isoforms

Human Molecular Genetics ◽

10.1093/hmg/ddaa154 ◽

2020 ◽

Vol 29 (R1) ◽

pp. R89-R99

Author(s):

Deivid Carvalho Rodrigues ◽

Marat Mufteev ◽

James Ellis

Keyword(s):

Dna Binding ◽

Rna Binding ◽

Rna Binding Proteins ◽

Alternative Polyadenylation ◽

Cell Types ◽

Protein Isoforms ◽

Translation Efficiency ◽

Mrna Isoforms ◽

Exon 2 ◽

Messenger Ribonucleic Acid

Abstract The methyl-CpG-binding protein 2 (MECP2) is a critical global regulator of gene expression. Mutations in MECP2 cause neurodevelopmental disorders including Rett syndrome (RTT). MECP2 exon 2 is spliced into two alternative messenger ribonucleic acid (mRNA) isoforms encoding MECP2-E1 or MECP2-E2 protein isoforms that differ in their N-termini. MECP2-E2, isolated first, was used to define the general roles of MECP2 in methyl-deoxyribonucleic acid (DNA) binding, targeting of transcriptional regulatory complexes, and its disease-causing impact in RTT. It was later found that MECP2-E1 is the most abundant isoform in the brain and its exon 1 is also mutated in RTT. MECP2 transcripts undergo alternative polyadenylation generating mRNAs with four possible 3′untranslated region (UTR) lengths ranging from 130 to 8600 nt. Together, the exon and 3′UTR isoforms display remarkable abundance disparity across cell types and tissues during development. These findings indicate discrete means of regulation and suggest that protein isoforms perform non-overlapping roles. Multiple regulatory programs have been explored to explain these disparities. DNA methylation patterns of the MECP2 promoter and first intron impact MECP2-E1 and E2 isoform levels. Networks of microRNAs and RNA-binding proteins also post-transcriptionally regulate the stability and translation efficiency of MECP2 3′UTR isoforms. Finally, distinctions in biophysical properties in the N-termini between MECP2-E1 and E2 lead to variable protein stabilities and DNA binding dynamics. This review describes the steps taken from the discovery of MECP2, the description of its key functions, and its association with RTT, to the emergence of evidence revealing how MECP2 isoforms are differentially regulated at the transcriptional, post-transcriptional and post-translational levels.

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The RNA-binding protein, Rasputin/G3BP, enhances the stability and translation of its target mRNAs

10.1101/2020.01.21.913079 ◽

2020 ◽

Author(s):

John D. Laver ◽

Jimmy Ly ◽

Allison K. Winn ◽

Angelo Karaiskakis ◽

Sichun Lin ◽

...

Keyword(s):

Microarray Analysis ◽

Rna Binding ◽

Rna Binding Proteins ◽

Rna Binding Protein ◽

Stress Granules ◽

Direct Role ◽

Target Mrnas ◽

Core Components ◽

The Stability

SUMMARYG3BP RNA-binding proteins are important components of stress granules (SGs). Here we analyze the role of Drosophila G3BP, Rasputin (RIN), in unstressed cells, where RIN is not SG associated. Immunoprecipitation followed by microarray analysis identified over 550 mRNAs that copurify with RIN. The mRNAs found in SGs are long and translationally silent. In contrast, we find that RIN-bound mRNAs, which encode core components of the transcription, splicing and translation machinery, are short, stable and highly translated. We show that RIN is associated with polysomes and provide evidence for a direct role for RIN and its human homologs in stabilizing and upregulating the translation of their target mRNAs. We propose that when cells are stressed the resulting incorporation of RIN/G3BPs into SGs sequesters them away from their short target mRNAs. This would downregulate the expression of these transcripts, even though they are not incorporated into stress granules.

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Crosstalk Between mRNA 3'-End Processing and Epigenetics

Frontiers in Genetics ◽

10.3389/fgene.2021.637705 ◽

2021 ◽

Vol 12 ◽

Author(s):

Lindsey V. Soles ◽

Yongsheng Shi

Keyword(s):

Histone Modifications ◽

Dynamic Process ◽

Rna Binding ◽

Rna Binding Proteins ◽

Alternative Polyadenylation ◽

Regulatory Mechanisms ◽

Epigenetic Mechanisms ◽

Cis Elements ◽

Mrna Isoforms ◽

Eukaryotic Genes

The majority of eukaryotic genes produce multiple mRNA isoforms by using alternative poly(A) sites in a process called alternative polyadenylation (APA). APA is a dynamic process that is highly regulated in development and in response to extrinsic or intrinsic stimuli. Mis-regulation of APA has been linked to a wide variety of diseases, including cancer, neurological and immunological disorders. Since the first example of APA was described 40 years ago, the regulatory mechanisms of APA have been actively investigated. Conventionally, research in this area has focused primarily on the roles of regulatory cis-elements and trans-acting RNA-binding proteins. Recent studies, however, have revealed important functions for epigenetic mechanisms, including DNA and histone modifications and higher-order chromatin structures, in APA regulation. Here we will discuss these recent findings and their implications for our understanding of the crosstalk between epigenetics and mRNA 3'-end processing.

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Emerging Roles for 3′ UTRs in Neurons

International Journal of Molecular Sciences ◽

10.3390/ijms21103413 ◽

2020 ◽

Vol 21 (10) ◽

pp. 3413

Author(s):

Bongmin Bae ◽

Pedro Miura

Keyword(s):

Translational Control ◽

Transcriptional Control ◽

Rna Binding ◽

Rna Binding Proteins ◽

Alternative Polyadenylation ◽

Mrna Localization ◽

Structural Features ◽

Mrna Isoforms ◽

Rna Sequences ◽

Neuronal Functions

The 3′ untranslated regions (3′ UTRs) of mRNAs serve as hubs for post-transcriptional control as the targets of microRNAs (miRNAs) and RNA-binding proteins (RBPs). Sequences in 3′ UTRs confer alterations in mRNA stability, direct mRNA localization to subcellular regions, and impart translational control. Thousands of mRNAs are localized to subcellular compartments in neurons—including axons, dendrites, and synapses—where they are thought to undergo local translation. Despite an established role for 3′ UTR sequences in imparting mRNA localization in neurons, the specific RNA sequences and structural features at play remain poorly understood. The nervous system selectively expresses longer 3′ UTR isoforms via alternative polyadenylation (APA). The regulation of APA in neurons and the neuronal functions of longer 3′ UTR mRNA isoforms are starting to be uncovered. Surprising roles for 3′ UTRs are emerging beyond the regulation of protein synthesis and include roles as RBP delivery scaffolds and regulators of alternative splicing. Evidence is also emerging that 3′ UTRs can be cleaved, leading to stable, isolated 3′ UTR fragments which are of unknown function. Mutations in 3′ UTRs are implicated in several neurological disorders—more studies are needed to uncover how these mutations impact gene regulation and what is their relationship to disease severity.

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Role of PUM RNA-Binding Proteins in Cancer

Cancers ◽

10.3390/cancers13010129 ◽

2021 ◽

Vol 13 (1) ◽

pp. 129

Author(s):

Maciej J. Smialek ◽

Erkut Ilaslan ◽

Marcin P. Sajek ◽

Jadwiga Jaruzelska

Keyword(s):

Rna Binding ◽

Rna Binding Proteins ◽

Alternative Polyadenylation ◽

Cancer Therapies ◽

Target Mrnas ◽

Non Coding Rna ◽

Specific Localization ◽

Transcriptional Gene Regulation ◽

Cancer Tissues

Until recently, post-transcriptional gene regulation (PTGR), in contrast to transcriptional regulation, was not extensively explored in cancer, even though it seems to be highly important. PUM proteins are well described in the PTGR of several organisms and contain the PUF RNA-binding domain that recognizes the UGUANAUA motif, located mostly in the 3′ untranslated region (3′UTR) of target mRNAs. Depending on the protein cofactors recruited by PUM proteins, target mRNAs are directed towards translation, repression, activation, degradation, or specific localization. Abnormal profiles of PUM expression have been shown in several types of cancer, in some of them being different for PUM1 and PUM2. This review summarizes the dysregulation of PUM1 and PUM2 expression in several cancer tissues. It also describes the regulatory mechanisms behind the activity of PUMs, including cooperation with microRNA and non-coding RNA machineries, as well as the alternative polyadenylation pathway. It also emphasizes the importance of future studies to gain a more complete picture of the role of PUM proteins in different types of cancer. Such studies may result in identification of novel targets for future cancer therapies.

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The Therapeutic Potential and Role of miRNA, lncRNA, and circRNA in Osteoarthritis

Current Gene Therapy ◽

10.2174/1566523219666190716092203 ◽

2019 ◽

Vol 19 (4) ◽

pp. 255-263 ◽

Cited By ~ 13

Author(s):

Yuangang Wu ◽

Xiaoxi Lu ◽

Bin Shen ◽

Yi Zeng

Keyword(s):

Gene Expression ◽

Gene Therapy ◽

Extracellular Matrix ◽

Inflammatory Reaction ◽

Noncoding Rna ◽

Rna Binding ◽

Rna Binding Proteins ◽

Protein Translation ◽

Cochrane Library

Background: Osteoarthritis (OA) is a disease characterized by progressive degeneration, joint hyperplasia, narrowing of joint spaces, and extracellular matrix metabolism. Recent studies have shown that the pathogenesis of OA may be related to non-coding RNA, and its pathological mechanism may be an effective way to reduce OA. Objective: The purpose of this review was to investigate the recent progress of miRNA, long noncoding RNA (lncRNA) and circular RNA (circRNA) in gene therapy of OA, discussing the effects of this RNA on gene expression, inflammatory reaction, apoptosis and extracellular matrix in OA. Methods: The following electronic databases were searched, including PubMed, EMBASE, Web of Science, and the Cochrane Library, for published studies involving the miRNA, lncRNA, and circRNA in OA. The outcomes included the gene expression, inflammatory reaction, apoptosis, and extracellular matrix. Results and Discussion: With the development of technology, miRNA, lncRNA, and circRNA have been found in many diseases. More importantly, recent studies have found that RNA interacts with RNA-binding proteins to regulate gene transcription and protein translation, and is involved in various pathological processes of OA, thus becoming a potential therapy for OA. Conclusion: In this paper, we briefly introduced the role of miRNA, lncRNA, and circRNA in the occurrence and development of OA and as a new target for gene therapy.

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Alternative polyadenylation: methods, mechanism, function, and role in cancer

Journal of Experimental & Clinical Cancer Research ◽

10.1186/s13046-021-01852-7 ◽

2021 ◽

Vol 40 (1) ◽

Cited By ~ 1

Author(s):

Yi Zhang ◽

Lian Liu ◽

Qiongzi Qiu ◽

Qing Zhou ◽

Jinwang Ding ◽

...

Keyword(s):

Gene Regulation ◽

Rna Binding ◽

Rna Binding Proteins ◽

Single Gene ◽

Alternative Polyadenylation ◽

Length Change ◽

Suppressor Gene ◽

Gene Expressions ◽

Related Factors ◽

Mrna Maturation

AbstractOccurring in over 60% of human genes, alternative polyadenylation (APA) results in numerous transcripts with differing 3’ends, thus greatly expanding the diversity of mRNAs and of proteins derived from a single gene. As a key molecular mechanism, APA is involved in various gene regulation steps including mRNA maturation, mRNA stability, cellular RNA decay, and protein diversification. APA is frequently dysregulated in cancers leading to changes in oncogenes and tumor suppressor gene expressions. Recent studies have revealed various APA regulatory mechanisms that promote the development and progression of a number of human diseases, including cancer. Here, we provide an overview of four types of APA and their impacts on gene regulation. We focus particularly on the interaction of APA with microRNAs, RNA binding proteins and other related factors, the core pre-mRNA 3’end processing complex, and 3’UTR length change. We also describe next-generation sequencing methods and computational tools for use in poly(A) signal detection and APA repositories and databases. Finally, we summarize the current understanding of APA in cancer and provide our vision for future APA related research.

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Current insights into the implications of m6A RNA methylation and autophagy interaction in human diseases

Cell & Bioscience ◽

10.1186/s13578-021-00661-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Xuechai Chen ◽

Jianan Wang ◽

Muhammad Tahir ◽

Fangfang Zhang ◽

Yuanyuan Ran ◽

...

Keyword(s):

Intervertebral Disc Degeneration ◽

Rna Binding ◽

Rna Binding Proteins ◽

Degradation Process ◽

Human Diseases ◽

Rna Modification ◽

Rna Methylation ◽

M6a Rna Methylation ◽

The Impact

AbstractAutophagy is a conserved degradation process crucial to maintaining the primary function of cellular and organismal metabolism. Impaired autophagy could develop numerous diseases, including cancer, cardiomyopathy, neurodegenerative disorders, and aging. N6-methyladenosine (m6A) is the most common RNA modification in eukaryotic cells, and the fate of m6A modified transcripts is controlled by m6A RNA binding proteins. m6A modification influences mRNA alternative splicing, stability, translation, and subcellular localization. Intriguingly, recent studies show that m6A RNA methylation could alter the expression of essential autophagy-related (ATG) genes and influence the autophagy function. Thus, both m6A modification and autophagy could play a crucial role in the onset and progression of various human diseases. In this review, we summarize the latest studies describing the impact of m6A modification in autophagy regulation and discuss the role of m6A modification-autophagy axis in different human diseases, including obesity, heart disease, azoospermatism or oligospermatism, intervertebral disc degeneration, and cancer. The comprehensive understanding of the m6A modification and autophagy interplay may help in interpreting their impact on human diseases and may aid in devising future therapeutic strategies.

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