scholarly journals Post-transcriptional regulation of microRNAs in cancer: From prediction to validation

Author(s):  
Sheril June Ankasha ◽  
Mohamad Nasir Shafiee ◽  
Norhazlina Abdul Wahab ◽  
Raja Affendi Raja Ali ◽  
Norfilza Mohd Mokhtar

MicroRNA (miRNA) is a small non-coding RNA with an established function to regulate genes at the post-transcriptional level leading to suppression or degradation of its messenger RNA expression (mRNA). Its dysregulation plays a vital role in a variety of biological and pathological processes including cancer. A lot of algorithms have been established to predict the target sites of miRNA, but experimentally identifying and validating its target region is still lacking. Guidance in experimental procedures is really needed to find genuine miRNA targets. Therefore, in this review, we provide an outline on the workflow in predicting and validating the targeted sites of miRNA using several methods as a guideline for the scientists. The final outcome of this type of experiment is essential to explore the major impact of miRNAmRNA interaction involved in the biological processes and to assist miRNA-based drug development in the future.

2012 ◽  
Vol 5 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Tareq B. Malas ◽  
Timothy Ravasi

MicroRNAs (miRNAs) are single-stranded non-coding RNA susually of 22 nucleotidesin length that play an important post-transcriptional regulation role in many organisms. MicroRNAs bind a seed sequence to the 3'-untranslated region (UTR) region of the target messenger RNA (mRNA), inducing degradation or inhibition of translation and resulting in a reduction in the protein level. This regulatory mechanism is central to many biological processes and perturbation could lead to diseases such as cancer. Given the biological importance, of miRNAs, there is a great need to identify and study their targets and functions. However, miRNAs are very difficult to clone in the lab and this has hindered the identification of novel miRNAs. Next-generation sequencing coupled with new computational tools has recently evolved to help researchers efficiently identify large numbers of novel miRNAs. In this review, we describe recent miRNA prediction tools and discuss their priorities, advantages and disadvantages.


2016 ◽  
Author(s):  
Mireya Plass ◽  
Simon H. Rasmussen ◽  
Anders Krogh

AbstractBackgroundMicroRNAs (miRNAs) are endogenous short non-coding RNAs involved in the regulation of gene expression at the post-transcriptional level typically by promoting destabilization or translational repression of target RNAs. Sometimes this regulation is absent or different, which likely is the result of interactions with other post-transcriptional factors, particularly RNA-binding proteins (RBPs). Despite the importance of the interactions between RBPs and miRNAs, little is known about how they affect post-transcriptional regulation in a global scale.ResultsIn this study, we have analyzed CLIP datasets of 49 RBPs in HEK293 cells with the aim of understanding the interplay between RBPs and miRNAs in post-transcriptional regulation. Our results show that RBPs bind preferentially in conserved regulatory hotspots that frequently contain miRNA target sites. This organization facilitates the competition and cooperation among RBPs and the regulation of miRNA target site accessibility. In some cases RBP enrichment on target sites correlates with miRNA expression, suggesting coordination between the regulatory factors. However, in most cases, competition among factors is the most plausible interpretation of our data. Upon AGO2 knockdown, transcripts that contain such hotspots that overlap target sites of expressed miRNAs in 3’UTRs are significantly less up-regulated than transcripts without them, suggesting that RBP binding limits miRNA accessibility.ConclusionsWe show that RBP binding is concentrated in regulatory hotspots in 3’UTRs. The presence of these hotspots facilitates the interaction among post-transcriptional regulators, that interact or compete with each other under different conditions. These hotspots are enriched in genes with regulatory functions such as DNA binding and RNA binding. Taken together, our results suggest that hotspots are important regulatory regions that define an extra layer of auto-regulatory control of post-transcriptional regulation.


Author(s):  
Xiang Yu ◽  
Bishwas Sharma ◽  
Brian D Gregory

Abstract Ribonucleotides within the various RNA molecules in eukaryotes are marked with more than 160 distinct covalent chemical modifications. These modifications include those that occur internally in messenger RNA (mRNA) molecules such as N6-methyladenosine (m6A) and 5-methylcytosine (m5C), as well as those that occur at the ends of the modified RNAs like the non-canonical 5′ end nicotinamide adenine dinucleotide (NAD+) cap modification of specific mRNAs. Recent findings have revealed that covalent RNA modifications can impact the secondary structure, translatability, functionality, stability and degradation of the RNA molecules in which they are included. Many of these covalent RNA additions have also been found to be dynamically added and removed through writer and eraser complexes, respectively, providing a new layer of epitranscriptome-mediated post-transcriptional regulation that regulates RNA quality and quantity in eukaryotic transcriptomes. Thus, it is not surprising that the regulation of RNA fate mediated by these epitranscriptomic marks has been demonstrated to have widespread effects on plant development and the responses of these organisms to abiotic and biotic stresses. In this review, we highlight recent progress focused on the study of the dynamic nature of these epitranscriptome marks and their roles in post-transcriptional regulation during plant development and response to environmental cues, with an emphasis on the mRNA modifications of non-canonical 5′ end NAD+ capping, m6A and several other internal RNA modifications.


2021 ◽  
Vol 22 (7) ◽  
pp. 3392
Author(s):  
Marina R. Alexander ◽  
Aaron M. Brice ◽  
Petrus Jansen van Vuren ◽  
Christina L. Rootes ◽  
Leon Tribolet ◽  
...  

The global COVID-19 pandemic caused by SARS-CoV-2 has resulted in over 2.2 million deaths. Disease outcomes range from asymptomatic to severe with, so far, minimal genotypic change to the virus so understanding the host response is paramount. Transcriptomics has become incredibly important in understanding host-pathogen interactions; however, post-transcriptional regulation plays an important role in infection and immunity through translation and mRNA stability, allowing tight control over potent host responses by both the host and the invading virus. Here, we apply ribosome profiling to assess post-transcriptional regulation of host genes during SARS-CoV-2 infection of a human lung epithelial cell line (Calu-3). We have identified numerous transcription factors (JUN, ZBTB20, ATF3, HIVEP2 and EGR1) as well as select antiviral cytokine genes, namely IFNB1, IFNL1,2 and 3, IL-6 and CCL5, that are restricted at the post-transcriptional level by SARS-CoV-2 infection and discuss the impact this would have on the host response to infection. This early phase restriction of antiviral transcripts in the lungs may allow high viral load and consequent immune dysregulation typically seen in SARS-CoV-2 infection.


1997 ◽  
Vol 328 (2) ◽  
pp. 393-399 ◽  
Author(s):  
B. Luis AGELLON ◽  
K. Sukhinder CHEEMA

To investigate the importance of the 3ʹ-untranslated region (UTR) of the mouse cholesterol 7α-hydroxylase (cyp7) mRNA in post-transcriptional regulation of expression of the cyp7 gene, chimaeric genes encoding mRNA containing the structural sequence of chloramphenicol acetyltransferase (CAT) linked to either the 3ʹ-UTR of the mouse cyp7 mRNA or the SV40 early gene mRNA were constructed. The human cytomegalovirus (CMV) promoter was used to drive the expression of all the chimaeric genes. Thus the transgenes had identical sequences in the promoter, the regions encoding the 5ʹ-UTR and translated sequence but differed in the region encoding the 3ʹ-UTR of their respective mRNA species. The transgene containing the entire cyp7 3ʹ-UTR (designated CMV.CAT.CYP7) gave rise to CAT activity in transfected hepatoma cells that was one-quarter of that obtained in cells transfected with the transgene containing the SV40 3ʹ-UTR (designated CMV.CAT.SV40). The 3ʹ-UTR of the cyp7 mRNA contains sequences resembling AU-rich elements (AREs). Deleting eight of nine putative AREs from the CYP7 3ʹ-UTR sequence increased the CAT activity to a level greater than that observed for CMV.CAT.SV40, whereas deletion of the intron region had no effect. These results show that the AREs of the 3ʹ-UTR of the cyp7 mRNA decrease transgene expression. Bile acids are known to repress the expression of the cyp7 gene. To test whether the 3ʹ-UTR of the cyp7 mRNA has a role in this process, the expression of the chimaeric genes was evaluated in hepatoma cells competent for bile acid uptake. Conjugated bile acids, but not unconjugated bile acids, further decreased the expression of the CMV.CAT.CYP7 transgene. The same bile acids had no effect on the expression of the CMV.CAT.SV40 transgene. Deletion of the intron from the cyp7 sequence did not alter the CAT activity compared with the parental plasmid, and also did not alter the sensitivity of the transgene to the conjugated bile acids. Deletion of the AREs from the cyp7 3ʹ-UTR, which increased the expression of the transgene, did not abolish the sensitivity of the transgene to repression by conjugated bile acids. Thus the 3ʹ-UTR of the mouse cyp7 mRNA also contains elements that facilitate the further repression of transgene expression in the presence of conjugated bile acids. The results indicate that the 3ʹ-UTR of the mouse cyp7 mRNA contains information specifying regulation at the post-transcriptional level.


2020 ◽  
Author(s):  
Paulina Podszywalow-Bartnicka ◽  
Magdalena Wolczyk ◽  
Katarzyna Piwocka

Post-transcriptional regulation is an important step of gene expression that allows to fine-tune the cellular protein profile (so called proteome) according to the current demands. That mechanism has been developed to aid survival under stress conditions, however it occurs to be hijacked by cancer cells. Adjustment of the protein profile remodels signaling in cancer cells to adapt to therapeutic treatment, thereby enabling persistence despite unfavorable environment or accumulating mutations. The proteome is shaped at the post-transcriptional level by numerous mechanisms such as alternative splicing, mRNA modifications and triage by RNA binding proteins, change of ribosome composition or signaling, which altogether regulate the translation process. This chapter is an overview of the translation disturbances found in leukemia and their role in development of the disease, with special focus on the possible therapeutic strategies tested in acute leukemia which target elements of those regulatory mechanisms.


Development ◽  
1999 ◽  
Vol 126 (15) ◽  
pp. 3371-3380
Author(s):  
Q. Tian ◽  
T. Nakayama ◽  
M.P. Dixon ◽  
J.L. Christian

The Xenopus Wnt-8 gene is transiently expressed in ventral and lateral mesoderm during gastrulation and plays a critical role in patterning these tissues. In the current study, we show that the spatial and temporal pattern of expression of endogenous Xwnt-8 is regulated, in part, at a post-transcriptional level. We have identified a novel sequence element in the 3′ untranslated region of the Xwnt-8 RNA that controls the polyadenylation status of reporter and endogenous Xwnt-8 RNAs, directs rapid RNA degradation beginning precisely at the early gastrula stage, and represses translation of transcripts throughout development. Expression of endogenous Xwnt-8 is normally downregulated within lateral (presomitic) mesoderm following gastrulation. We demonstrate that rapid degradation of Xwnt-8 transcripts, mediated by these regulatory elements in the 3′ untranslated region, is essential to this process and that downregulation is required to prevent overcommitment of somitic cells to a myogenic fate. These studies demonstrate a role for post-transcriptional regulation of zygotic gene expression in vertebrate embryonic patterning.


Oncogene ◽  
2002 ◽  
Vol 21 (10) ◽  
pp. 1625-1631 ◽  
Author(s):  
Séverine Lottin ◽  
Anne-Sophie Vercoutter-Edouart ◽  
Eric Adriaenssens ◽  
Xavier Czeszak ◽  
Jérôme Lemoine ◽  
...  

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