scholarly journals SERRATE interacts with the nuclear exosome targeting (NEXT) complex to degrade primary miRNA precursors in Arabidopsis

2020 ◽  
Author(s):  
Mateusz Bajczyk ◽  
Heike Lange ◽  
Dawid Bielewicz ◽  
Lukasz Szewc ◽  
Susheel Sagar Bhat ◽  
...  

AbstractSERRATE/ARS2 is a conserved RNA effector protein involved in transcription, processing and export of different types of RNAs. In Arabidopsis, the best-studied function of SERRATE (SE) is to promote miRNA processing. Here, we report that SE interacts with the Nuclear Exosome Targeting (NEXT) complex, comprising the RNA helicase HEN2, the RNA binding protein RBM7 and one of the two zinc-knuckle proteins ZCCHC8A/ZCCHC8B. The identification of common targets of SE and HEN2 by RNA-seq supports the idea that SE cooperates with NEXT for RNA surveillance by the nuclear exosome. Among the RNA targets accumulating in absence of SE or NEXT are miRNA precursors. Loss of NEXT components results in the accumulation of pri-miRNAs without affecting levels of miRNAs, indicating that NEXT is, unlike SE, not required for miRNA processing. As compared to se-2, se-2 hen2-2 double mutants showed increased accumulation of pri-miRNAs, but partially restored levels of mature miRNAs and attenuated developmental defects. We propose that the slow degradation of pri-miRNAs caused by loss of HEN2 compensates for the poor miRNA processing efficiency in se-2 mutants, and that SE regulates miRNA biogenesis through its double contribution in promoting miRNA processing but also pri-miRNA degradation through the recruitment of the NEXT complex.

2020 ◽  
Vol 48 (12) ◽  
pp. 6839-6854 ◽  
Author(s):  
Mateusz Bajczyk ◽  
Heike Lange ◽  
Dawid Bielewicz ◽  
Lukasz Szewc ◽  
Susheel S Bhat ◽  
...  

Abstract SERRATE/ARS2 is a conserved RNA effector protein involved in transcription, processing and export of different types of RNAs. In Arabidopsis, the best-studied function of SERRATE (SE) is to promote miRNA processing. Here, we report that SE interacts with the nuclear exosome targeting (NEXT) complex, comprising the RNA helicase HEN2, the RNA binding protein RBM7 and one of the two zinc-knuckle proteins ZCCHC8A/ZCCHC8B. The identification of common targets of SE and HEN2 by RNA-seq supports the idea that SE cooperates with NEXT for RNA surveillance by the nuclear exosome. Among the RNA targets accumulating in absence of SE or NEXT are miRNA precursors. Loss of NEXT components results in the accumulation of pri-miRNAs without affecting levels of miRNAs, indicating that NEXT is, unlike SE, not required for miRNA processing. As compared to se-2, se-2 hen2-2 double mutants showed increased accumulation of pri-miRNAs, but partially restored levels of mature miRNAs and attenuated developmental defects. We propose that the slow degradation of pri-miRNAs caused by loss of HEN2 compensates for the poor miRNA processing efficiency in se-2 mutants, and that SE regulates miRNA biogenesis through its double contribution in promoting miRNA processing but also pri-miRNA degradation through the recruitment of the NEXT complex.


2020 ◽  
Vol 117 (29) ◽  
pp. 17429-17437
Author(s):  
Shuai Gao ◽  
Jingyu Wang ◽  
Ning Jiang ◽  
Shiting Zhang ◽  
Yuan Wang ◽  
...  

Biogenesis of plant microRNAs (miRNAs) takes place in nuclear dicing bodies (D-bodies), where the ribonulease III-type enzyme Dicer-like 1 (DCL1) processes primary transcripts of miRNAs (pri-miRNAs) into miRNA/miRNA* (*, passenger strand) duplexes from either base-to-loop or loop-to-base directions. Hyponastic Leaves 1 (HYL1), a double-stranded RNA-binding protein, is crucial for efficient and accurate processing. However, whether HYL1 has additional function remains unknown. Here, we report that HYL1 plays a noncanonical role in protecting pri-miRNAs from nuclear exosome attack in addition to ensuring processing. Loss of functions in SOP1 or HEN2, two cofactors of the nucleoplasmic exosome, significantly suppressed the morphological phenotypes ofhyl1-2. Remarkably, mature miRNAs generated from loop-to-base processing were partially but preferentially restored in thehyl1 sop1andhyl1 hen2double mutants. Accordingly, loop-to-base–processed pri-miRNAs accumulated to higher levels in double mutants. In addition, dysfunction of HEN2, but not of SOP1, inhyl1-2resulted in overaccumulation of many base-to-loop–processed pri-miRNAs, with most of their respective miRNAs unaffected. In summary, our findings reveal an antagonistic action of exosome in pri-miRNA biogenesis and uncover dual roles of HYL1 in stabilizing and processing of pri-miRNAs.


2008 ◽  
Vol 28 (17) ◽  
pp. 5446-5457 ◽  
Author(s):  
Laura Milligan ◽  
Laurence Decourty ◽  
Cosmin Saveanu ◽  
Juri Rappsilber ◽  
Hugo Ceulemans ◽  
...  

ABSTRACT A genome-wide screen for synthetic lethal (SL) interactions with loss of the nuclear exosome cofactors Rrp47/Lrp1 or Air1 identified 3′→5′ exonucleases, the THO complex required for mRNP assembly, and Ynr024w (Mpp6). SL interactions with mpp6Δ were confirmed for rrp47Δ and nuclear exosome component Rrp6. The results of bioinformatic analyses revealed homology between Mpp6 and a human exosome cofactor, underlining the high conservation of the RNA surveillance system. Mpp6 is an RNA binding protein that physically associates with the exosome and was localized throughout the nucleus. The results of functional analyses demonstrated roles for Mpp6 in the surveillance of both pre-rRNA and pre-mRNAs and in the degradation of “cryptic” noncoding RNAs (ncRNAs) derived from intergenic regions and the ribosomal DNA spacer heterochromatin. Strikingly, these ncRNAs are also targeted by other exosome cofactors, including Rrp47, the TRAMP complex (which includes Air1), and the Nrd1/Nab3 complex, and are degraded by both Rrp6 and the core exosome. Heterochromatic transcripts and other ncRNAs are characterized by very rapid degradation, and we predict that functional redundancy is an important feature of ncRNA metabolism.


PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0258550
Author(s):  
Upendra Kumar Pradhan ◽  
Nitesh Kumar Sharma ◽  
Prakash Kumar ◽  
Ashwani Kumar ◽  
Sagar Gupta ◽  
...  

Formation of mature miRNAs and their expression is a highly controlled process. It is very much dependent upon the post-transcriptional regulatory events. Recent findings suggest that several RNA binding proteins beyond Drosha/Dicer are involved in the processing of miRNAs. Deciphering of conditional networks for these RBP-miRNA interactions may help to reason the spatio-temporal nature of miRNAs which can also be used to predict miRNA profiles. In this direction, >25TB of data from different platforms were studied (CLIP-seq/RNA-seq/miRNA-seq) to develop Bayesian causal networks capable of reasoning miRNA biogenesis. The networks ably explained the miRNA formation when tested across a large number of conditions and experimentally validated data. The networks were modeled into an XGBoost machine learning system where expression information of the network components was found capable to quantitatively explain the miRNAs formation levels and their profiles. The models were developed for 1,204 human miRNAs whose accurate expression level could be detected directly from the RNA-seq data alone without any need of doing separate miRNA profiling experiments like miRNA-seq or arrays. A first of its kind, miRbiom performed consistently well with high average accuracy (91%) when tested across a large number of experimentally established data from several conditions. It has been implemented as an interactive open access web-server where besides finding the profiles of miRNAs, their downstream functional analysis can also be done. miRbiom will help to get an accurate prediction of human miRNAs profiles in the absence of profiling experiments and will be an asset for regulatory research areas. The study also shows the importance of having RBP interaction information in better understanding the miRNAs and their functional projectiles where it also lays the foundation of such studies and software in future.


2016 ◽  
Vol 113 (38) ◽  
pp. 10720-10725 ◽  
Author(s):  
Tomohito Yamasaki ◽  
Masayuki Onishi ◽  
Eun-Jeong Kim ◽  
Heriberto Cerutti ◽  
Takeshi Ohama

Canonical microRNAs (miRNAs) are embedded in duplexed stem–loops in long precursor transcripts and are excised by sequential cleavage by DICER nuclease(s). In this miRNA biogenesis pathway, dsRNA-binding proteins play important roles in animals and plants by assisting DICER. However, these RNA-binding proteins are poorly characterized in unicellular organisms. Here we report that a unique RNA-binding protein, Dull slicer-16 (DUS16), plays an essential role in processing of primary-miRNA (pri-miRNA) transcripts in the unicellular green alga Chlamydomonas reinhardtii. In animals and plants, dsRNA-binding proteins involved in miRNA biogenesis harbor two or three dsRNA-binding domains (dsRBDs), whereas DUS16 contains one dsRBD and also an ssRNA-binding domain (RRM). The null mutant of DUS16 showed a drastic reduction in most miRNA species. Production of these miRNAs was complemented by expression of full-length DUS16, but the expression of RRM- or dsRBD-truncated DUS16 did not restore miRNA production. Furthermore, DUS16 is predominantly localized to the nucleus and associated with nascent (unspliced form) pri-miRNAs and the DICER-LIKE 3 protein. These results suggest that DUS16 recognizes pri-miRNA transcripts cotranscriptionally and promotes their processing into mature miRNAs as a component of a microprocessor complex. We propose that DUS16 is an essential factor for miRNA production in Chlamydomonas and, because DUS16 is functionally similar to the dsRNA-binding proteins involved in miRNA biogenesis in animals and land plants, our report provides insight into this mechanism in unicellular eukaryotes.


2018 ◽  
Vol 19 (12) ◽  
pp. 4075 ◽  
Author(s):  
Martyna Urbanek-Trzeciak ◽  
Edyta Jaworska ◽  
Wlodzimierz Krzyzosiak

MicroRNAs (miRNAs) are short, non-coding post-transcriptional gene regulators. In mammalian cells, mature miRNAs are produced from primary precursors (pri-miRNAs) using canonical protein machinery, which includes Drosha/DGCR8 and Dicer, or the non-canonical mirtron pathway. In plant cells, mature miRNAs are excised from pri-miRNAs by the DICER-LIKE1 (DCL1) protein complex. The involvement of multiple regulatory proteins that bind directly to distinct miRNA precursors in a sequence- or structure-dependent manner adds to the complexity of the miRNA maturation process. Here, we present a web server that enables searches for miRNA precursors that can be recognized by diverse RNA-binding proteins based on known sequence motifs to facilitate the identification of other proteins involved in miRNA biogenesis. The database used by the web server contains known human, murine, and Arabidopsis thaliana pre-miRNAs. The web server can also be used to predict new RNA-binding protein motifs based on a list of user-provided sequences. We show examples of miRNAmotif applications, presenting precursors that contain motifs recognized by Lin28, MCPIP1, and DGCR8 and predicting motifs within pre-miRNA precursors that are recognized by two DEAD-box helicases—DDX1 and DDX17. miRNAmotif is released as an open-source software under the MIT License. The code is available at GitHub (www.github.com/martynaut/mirnamotif). The webserver is freely available at http://mirnamotif.ibch.poznan.pl.


2021 ◽  
Vol 22 (13) ◽  
pp. 6765
Author(s):  
Izabela Suster ◽  
Yue Feng

MicroRNAs (miRNAs) are small, non-coding RNAs that function as endogenous gene silencers. Soon after the discovery of miRNAs, a subset of brain-enriched and brain-specific miRNAs were identified and significant advancements were made in delineating miRNA function in brain development. However, understanding the molecular mechanisms that regulate miRNA biogenesis in normal and diseased brains has become a prevailing challenge. Besides transcriptional regulation of miRNA host genes, miRNA processing intermediates are subjected to multifaceted regulation by canonical miRNA processing enzymes, RNA binding proteins (RBPs) and epitranscriptomic modifications. Further still, miRNA activity can be regulated by the sponging activity of other non-coding RNA classes, namely circular RNAs (circRNAs) and long non-coding RNAs (lncRNAs). Differential abundance of these factors in neuronal and glial lineages partly underlies the spatiotemporal expression and function of lineage-specific miRNAs. Here, we review the continuously evolving understanding of the regulation of neuronal and glial miRNA biogenesis at the transcriptional and posttranscriptional levels and the cooperativity of miRNA species in targeting key mRNAs to drive lineage-specific development. In addition, we review dysregulation of neuronal and glial miRNAs and the detrimental impacts which contribute to developmental brain disorders.


2014 ◽  
Vol 42 (15) ◽  
pp. 9925-9936 ◽  
Author(s):  
Tino Köster ◽  
Katja Meyer ◽  
Claus Weinholdt ◽  
Lisa M. Smith ◽  
Martina Lummer ◽  
...  

Abstract The hnRNP-like glycine-rich RNA-binding protein AtGRP7 regulates pre-mRNA splicing in Arabidopsis. Here we used small RNA-seq to show that AtGRP7 also affects the miRNA inventory. AtGRP7 overexpression caused a significant reduction in the level of 30 miRNAs and an increase for 14 miRNAs with a minimum log2 fold change of ±0.5. Overaccumulation of several pri-miRNAs including pri-miR398b, pri-miR398c, pri-miR172b, pri-miR159a and pri-miR390 at the expense of the mature miRNAs suggested that AtGRP7 affects pri-miRNA processing. Indeed, RNA immunoprecipitation revealed that AtGRP7 interacts with these pri-miRNAs in vivo. Mutation of an arginine in the RNA recognition motif abrogated in vivo binding and the effect on miRNA and pri-miRNA levels, indicating that AtGRP7 inhibits processing of these pri-miRNAs by direct binding. In contrast, pri-miRNAs of selected miRNAs that were elevated or not changed in response to high AtGRP7 levels were not bound in vivo. Reduced accumulation of miR390, an initiator of trans-acting small interfering RNA (ta-siRNA) formation, also led to lower TAS3 ta-siRNA levels and increased mRNA expression of the target AUXIN RESPONSE FACTOR4. Furthermore, AtGRP7 affected splicing of pri-miR172b and pri-miR162a. Thus, AtGRP7 is an hnRNP-like protein with a role in processing of pri-miRNAs in addition to its role in pre-mRNA splicing.


2019 ◽  
Author(s):  
Dawid Bielewicz ◽  
Jakub Dolata ◽  
Mateusz Bajczyk ◽  
Lukasz Szewc ◽  
Tomasz Gulanicz ◽  
...  

AbstractDRB1 (HYL1) is a double-stranded RNA binding protein involved in miRNA processing in plants. It is a core component of the Microprocessor complex and enhances the efficiency and precision of miRNA processing by DCL1 protein. In this work, we report a novel function of DRB1 protein in the transcription of MIR genes. DRB1 co-localizes with RNA Polymerase II and affects its distribution along MIR genes. Moreover, proteomic experiments revealed that DRB1 protein interacts with many transcription factors. Finally, we show that the action of DRB1 is not limited to MIR genes as it impacts expression of many other genes, majority of which are involved in plant response to light. These discoveries add DRB1 as another player of gene regulation at transcriptional level, independent of its role in miRNA biogenesis.


2020 ◽  
Vol 117 (38) ◽  
pp. 23982-23990 ◽  
Author(s):  
Shengjun Li ◽  
Mu Li ◽  
Kan Liu ◽  
Huimin Zhang ◽  
Shuxin Zhang ◽  
...  

MAC5 is a component of the conserved MOS4-associated complex. It plays critical roles in development and immunity. Here we report that MAC5 is required for microRNA (miRNA) biogenesis. MAC5 interacts with Serrate (SE), which is a core component of the microprocessor that processes primary miRNA transcripts (pri-miRNAs) into miRNAs and binds the stem-loop region of pri-miRNAs. MAC5 is essential for both the efficient processing and the stability of pri-miRNAs. Interestingly, the reduction of pri-miRNA levels inmac5is partially caused by XRN2/XRN3, the nuclear-localized 5′-to-3′ exoribonucleases, and depends on SE. These results reveal that MAC5 plays a dual role in promoting pri-miRNA processing and stability through its interaction with SE and/or pri-miRNAs. This study also uncovers that pri-miRNAs need to be protected from nuclear RNA decay machinery, which is connected to the microprocessor.


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