scholarly journals m6A RNA methylation regulates promoter proximal pausing of RNA Polymerase II

Author(s):  
Junaid Akhtar ◽  
Yoan Renaud ◽  
Steffen Albrecht ◽  
Yad Ghavi-Helm ◽  
Jean-Yves Roignant ◽  
...  

AbstractRNA Polymerase II (RNAP II) pausing is essential to precisely control gene expression and is critical for development of metazoans. Here, we show that the m6A RNA modification regulates promoter-proximal RNAP II pausing. The m6A methyltransferase complex (MTC), with the nuclear reader Ythdc1, are recruited to gene promoters. Depleting the m6A MTC leads to a decrease in RNAP II pause release and in Ser2P occupancy on the gene body, and affects nascent RNA transcription. Tethering Mettl3 to a heterologous gene promoter is sufficient to increase RNAP II pause release, an effect that relies on its m6A catalytic domain. Collectively, our data reveal an important link between RNAP II pausing and the m6A RNA modification, thus adding another layer to m6A-mediated gene regulation.

2019 ◽  
Vol 21 (1) ◽  
pp. 135 ◽  
Author(s):  
Sergey A. Proshkin ◽  
Elena K. Shematorova ◽  
George V. Shpakovski

Rpb11 subunit of RNA polymerase II of Eukaryotes is related to N-terminal domain of eubacterial α subunit and forms a complex with Rpb3 subunit analogous to prokaryotic α2 homodimer, which is involved in RNA polymerase assembly and promoter recognition. In humans, a POLR2J gene family has been identified that potentially encodes several hRPB11 proteins differing mainly in their short C-terminal regions. The functions of the different human specific isoforms are still mainly unknown. To further characterize the minor human specific isoform of RNA polymerase II subunit hRPB11bα, the only one from hRPB11 (POLR2J) homologues that can replace its yeast counterpart in vivo, we used it as bait in a yeast two-hybrid screening of a human fetal brain cDNA library. By this analysis and subsequent co-purification assay in vitro, we identified transcription factor ATF4 as a prominent partner of the minor RNA polymerase II (RNAP II) subunit hRPB11bα. We demonstrated that the hRPB11bα interacts with leucine b-Zip domain located on the C-terminal part of ATF4. Overexpression of ATF4 activated the reporter more than 10-fold whereas co-transfection of hRPB11bα resulted in a 2.5-fold enhancement of ATF4 activation. Our data indicate that the mode of interaction of human RNAP II main (containing major for of hRPB11 subunit) and minor (containing hRPB11bα isoform of POLR2J subunit) transcription enzymes with ATF4 is certainly different in the two complexes involving hRPB3–ATF4 (not hRPB11a–ATF4) and hRpb11bα–ATF4 platforms in the first and the second case, respectively. The interaction of hRPB11bα and ATF4 appears to be necessary for the activation of RNA polymerase II containing the minor isoform of the hRPB11 subunit (POLR2J) on gene promoters regulated by this transcription factor. ATF4 activates transcription by directly contacting RNA polymerase II in the region of the heterodimer of α-like subunits (Rpb3–Rpb11) without involving a Mediator, which provides fast and highly effective activation of transcription of the desired genes. In RNA polymerase II of Homo sapiens that contains plural isoforms of the subunit hRPB11 (POLR2J), the strength of the hRPB11–ATF4 interaction appeared to be isoform-specific, providing the first functional distinction between the previously discovered human forms of the Rpb11 subunit.


2021 ◽  
Author(s):  
Junaid Akhtar ◽  
Yoan Renaud ◽  
Steffen Albrecht ◽  
Yad Ghavi-Helm ◽  
Jean-Yves Roignant ◽  
...  

1993 ◽  
Vol 13 (10) ◽  
pp. 6403-6415 ◽  
Author(s):  
S Connelly ◽  
W Filipowicz

Formation of the 3' ends of RNA polymerase II (Pol II)-specific U small nuclear RNAs (U snRNAs) in vertebrate cells is dependent upon transcription initiation from the U snRNA gene promoter. Moreover, U snRNA promoters are unable to direct the synthesis of functional polyadenylated mRNAs. In this work, we have investigated whether U snRNA 3'-end formation and transcription initiation are also coupled in plants. We have first characterized the requirements for 3'-end formation of an Arabidopsis U2 snRNA expressed in transfected protoplasts of Nicotiana plumbaginifolia. We found that the 3'-end-adjacent sequence CA (N)3-10AGTNNAA, conserved in plant Pol II-specific U snRNA genes, is essential for the 3'-end formation of U2 transcripts and, similar to the vertebrate 3' box, is highly tolerant to mutation. The 3'-flanking regions of an Arabidopsis U5 and a maize U2 snRNA gene can effectively substitute for the Arabidopsis U2 3'-end formation signal, indicating that these signals are functionally equivalent among different Pol II-transcribed snRNA genes. The plant U snRNA 3'-end formation signal can be recognized irrespective of whether transcription initiation occurs at U snRNA or mRNA gene promoters, although efficiency of 3' box utilization is higher when transcription initiation occurs at the U snRNA promoter. Moreover, transcripts initiated from the U2 gene promoter can be spliced and polyadenylated. Transcription from a Pol III-specific plant U snRNA gene promoter is not compatible with polyadenylation. Finally, we reveal that initiation at a Pol II-specific plant U snRNA gene promoter can occur in the absence of the snRNA coding region and a functional snRNA 3'-end formation signal, demonstrating that these sequences play no role in determining the RNA polymerase specificity of plant U snRNA genes.


1993 ◽  
Vol 13 (10) ◽  
pp. 6403-6415
Author(s):  
S Connelly ◽  
W Filipowicz

Formation of the 3' ends of RNA polymerase II (Pol II)-specific U small nuclear RNAs (U snRNAs) in vertebrate cells is dependent upon transcription initiation from the U snRNA gene promoter. Moreover, U snRNA promoters are unable to direct the synthesis of functional polyadenylated mRNAs. In this work, we have investigated whether U snRNA 3'-end formation and transcription initiation are also coupled in plants. We have first characterized the requirements for 3'-end formation of an Arabidopsis U2 snRNA expressed in transfected protoplasts of Nicotiana plumbaginifolia. We found that the 3'-end-adjacent sequence CA (N)3-10AGTNNAA, conserved in plant Pol II-specific U snRNA genes, is essential for the 3'-end formation of U2 transcripts and, similar to the vertebrate 3' box, is highly tolerant to mutation. The 3'-flanking regions of an Arabidopsis U5 and a maize U2 snRNA gene can effectively substitute for the Arabidopsis U2 3'-end formation signal, indicating that these signals are functionally equivalent among different Pol II-transcribed snRNA genes. The plant U snRNA 3'-end formation signal can be recognized irrespective of whether transcription initiation occurs at U snRNA or mRNA gene promoters, although efficiency of 3' box utilization is higher when transcription initiation occurs at the U snRNA promoter. Moreover, transcripts initiated from the U2 gene promoter can be spliced and polyadenylated. Transcription from a Pol III-specific plant U snRNA gene promoter is not compatible with polyadenylation. Finally, we reveal that initiation at a Pol II-specific plant U snRNA gene promoter can occur in the absence of the snRNA coding region and a functional snRNA 3'-end formation signal, demonstrating that these sequences play no role in determining the RNA polymerase specificity of plant U snRNA genes.


2005 ◽  
Vol 83 (4) ◽  
pp. 497-504 ◽  
Author(s):  
Benoit Coulombe ◽  
Marie-France Langelier

High resolution X-ray crystal structures of multisubunit RNA polymerases (RNAP) have contributed to our understanding of transcriptional mechanisms. They also provided a powerful guide for the design of experiments aimed at further characterizing the molecular stages of the transcription reaction. Our laboratory used tandem-affinity peptide purification in native conditions to isolate human RNAP II variants that had site-specific mutations in structural elements located strategically within the enzyme's catalytic center. Both in vitro and in vivo analyses of these mutants revealed novel features of the catalytic mechanisms involving this enzyme.Key words: RNA polymerase II, transcriptional mechanisms, mutational analysis, mRNA synthesis.


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Mohammad Burhan Uddin ◽  
Zhishan Wang ◽  
Chengfeng Yang

AbstractThe m6A RNA methylation is the most prevalent internal modification in mammalian mRNAs which plays critical biological roles by regulating vital cellular processes. Dysregulations of the m6A modification due to aberrant expression of its regulatory proteins are frequently observed in many pathological conditions, particularly in cancer. Normal cells undergo malignant transformation via activation or modulation of different oncogenic signaling pathways through complex mechanisms. Accumulating evidence showing regulation of oncogenic signaling pathways at the epitranscriptomic level has added an extra layer of the complexity. In particular, recent studies demonstrated that, in many types of cancers various oncogenic signaling pathways are modulated by the m6A modification in the target mRNAs as well as noncoding RNA transcripts. m6A modifications in these RNA molecules control their fate and metabolism by regulating their stability, translation or subcellular localizations. In this review we discussed recent exciting studies on oncogenic signaling pathways that are modulated by the m6A RNA modification and/or their regulators in cancer and provided perspectives for further studies. The regulation of oncogenic signaling pathways by the m6A modification and its regulators also render them as potential druggable targets for the treatment of cancer.


2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Fei Ye ◽  
Tianzhu Wang ◽  
Xiaoxin Wu ◽  
Jie Liang ◽  
Jiaoxing Li ◽  
...  

Abstract Background Progressive multiple sclerosis (PMS) is an uncommon and severe subtype of MS that worsens gradually and leads to irreversible disabilities in young adults. Currently, there are no applicable or reliable biomarkers to distinguish PMS from relapsing–remitting multiple sclerosis (RRMS). Previous studies have demonstrated that dysfunction of N6-methyladenosine (m6A) RNA modification is relevant to many neurological disorders. Thus, the aim of this study was to explore the diagnostic biomarkers for PMS based on m6A regulatory genes in the cerebrospinal fluid (CSF). Methods Gene expression matrices were downloaded from the ArrayExpress database. Then, we identified differentially expressed m6A regulatory genes between MS and non-MS patients. MS clusters were identified by consensus clustering analysis. Next, we analyzed the correlation between clusters and clinical characteristics. The random forest (RF) algorithm was applied to select key m6A-related genes. The support vector machine (SVM) was then used to construct a diagnostic gene signature. Receiver operating characteristic (ROC) curves were plotted to evaluate the accuracy of the diagnostic model. In addition, CSF samples from MS and non-MS patients were collected and used for external validation, as evaluated by an m6A RNA Methylation Quantification Kit and by real-time quantitative polymerase chain reaction. Results The 13 central m6A RNA methylation regulators were all upregulated in MS patients when compared with non-MS patients. Consensus clustering analysis identified two clusters, both of which were significantly associated with MS subtypes. Next, we divided 61 MS patients into a training set (n = 41) and a test set (n = 20). The RF algorithm identified eight feature genes, and the SVM method was successfully applied to construct a diagnostic model. ROC curves revealed good performance. Finally, the analysis of 11 CSF samples demonstrated that RRMS samples exhibited significantly higher levels of m6A RNA methylation and higher gene expression levels of m6A-related genes than PMS samples. Conclusions The dynamic modification of m6A RNA methylation is involved in the progression of MS and could potentially represent a novel CSF biomarker for diagnosing MS and distinguishing PMS from RRMS in the early stages of the disease.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xuechai Chen ◽  
Jianan Wang ◽  
Muhammad Tahir ◽  
Fangfang Zhang ◽  
Yuanyuan Ran ◽  
...  

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.


2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Xiulin Jiang ◽  
Baiyang Liu ◽  
Zhi Nie ◽  
Lincan Duan ◽  
Qiuxia Xiong ◽  
...  

AbstractN6-methyladenosine (m6A) is the most prevalent, abundant and conserved internal cotranscriptional modification in eukaryotic RNAs, especially within higher eukaryotic cells. m6A modification is modified by the m6A methyltransferases, or writers, such as METTL3/14/16, RBM15/15B, ZC3H3, VIRMA, CBLL1, WTAP, and KIAA1429, and, removed by the demethylases, or erasers, including FTO and ALKBH5. It is recognized by m6A-binding proteins YTHDF1/2/3, YTHDC1/2 IGF2BP1/2/3 and HNRNPA2B1, also known as “readers”. Recent studies have shown that m6A RNA modification plays essential role in both physiological and pathological conditions, especially in the initiation and progression of different types of human cancers. In this review, we discuss how m6A RNA methylation influences both the physiological and pathological progressions of hematopoietic, central nervous and reproductive systems. We will mainly focus on recent progress in identifying the biological functions and the underlying molecular mechanisms of m6A RNA methylation, its regulators and downstream target genes, during cancer progression in above systems. We propose that m6A RNA methylation process offer potential targets for cancer therapy in the future.


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