scholarly journals The MicroRNA Landscape of MYCN-Amplified Neuroblastoma

2021 ◽  
Vol 11 ◽  
Author(s):  
Danny Misiak ◽  
Sven Hagemann ◽  
Jessica L. Bell ◽  
Bianca Busch ◽  
Marcell Lederer ◽  
...  

MYCN gene amplification and upregulated expression are major hallmarks in the progression of high-risk neuroblastoma. MYCN expression and function in modulating gene synthesis in neuroblastoma is controlled at virtually every level, including poorly understood regulation at the post-transcriptional level. MYCN modulates the expression of various microRNAs including the miR-17-92 cluster. MYCN mRNA expression itself is subjected to the control by miRNAs, most prominently the miR-17-92 cluster that balances MYCN expression by feed-back regulation. This homeostasis seems disturbed in neuroblastoma where MYCN upregulation coincides with severely increased expression of the miR-17-92 cluster. In the presented study, we applied high-throughput next generation sequencing to unravel the miRNome in a cohort of 97 neuroblastomas, representing all clinical stages. Aiming to reveal the MYCN-dependent miRNome, we evaluate miRNA expression in MYCN-amplified as well as none amplified tumor samples. In correlation with survival data analysis of differentially expressed miRNAs, we present various putative oncogenic as well as tumor suppressive miRNAs in neuroblastoma. Using microRNA trapping by RNA affinity purification, we provide a comprehensive view of MYCN-regulatory miRNAs in neuroblastoma-derived cells, confirming a pivotal role of the miR-17-92 cluster and moderate association by the let-7 miRNA family. Attempting to decipher how MYCN expression escapes elevated expression of inhibitory miRNAs, we present evidence that RNA-binding proteins like the IGF2 mRNA binding protein 1 reduce miRNA-directed downregulation of MYCN in neuroblastoma. Our findings emphasize the potency of post-transcriptional regulation of MYCN in neuroblastoma and unravel new avenues to pursue inhibition of this potent oncogene.

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.


2020 ◽  
Vol 21 (23) ◽  
pp. 9319
Author(s):  
Toru Suzuki ◽  
Shungo Adachi ◽  
Chisato Kikuguchi ◽  
Shinsuke Shibata ◽  
Saori Nishijima ◽  
...  

Transcripts of alpha-fetoprotein (Afp), H19, and insulin-like growth factor 2 (Igf2) genes are highly expressed in mouse fetal liver, but decrease drastically during maturation. While transcriptional regulation of these genes has been well studied, the post-transcriptional regulation of their developmental decrease is poorly understood. Here, we show that shortening of poly(A) tails and subsequent RNA decay are largely responsible for the postnatal decrease of Afp, H19, and Igf2 transcripts in mouse liver. IGF2 mRNA binding protein 1 (IMP1), which regulates stability and translation efficiency of target mRNAs, binds to these fetal liver transcripts. When IMP1 is exogenously expressed in mouse adult liver, fetal liver transcripts show higher expression and possess longer poly(A) tails, suggesting that IMP1 stabilizes them. IMP1 declines concomitantly with fetal liver transcripts as liver matures. Instead, RNA-binding proteins (RBPs) that promote RNA decay, such as cold shock domain containing protein E1 (CSDE1), K-homology domain splicing regulatory protein (KSRP), and CUG-BP1 and ETR3-like factors 1 (CELF1), bind to 3′ regions of fetal liver transcripts. These data suggest that transitions among RBPs associated with fetal liver transcripts shift regulation from stabilization to decay, leading to a postnatal decrease in those fetal transcripts.


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.


2021 ◽  
Author(s):  
Nicholas S. Wilcox ◽  
Timur O. Yarovinsky ◽  
Prakruti Pandya ◽  
Vinod S. Ramgolam ◽  
Albertomaria Moro ◽  
...  

SummaryTissue homeostasis and repair are orchestrated by resident and newly recruited macrophages that alter their gene expression program in response to changes in tissue microenvironment. Embryonic macrophages, such as fetal liver derived macrophages (FLDM) seed the organs, including heart and lung during embryonic development and persist throughout the adult lifetime, while bone marrow-derived macrophages (BMDM) are recruited following an acute perturbation. Transcriptome analyses of FLDM and BMDM identified differences between them at the level of RNA expression, which correlates imperfectly with protein levels. Post-transcriptional regulation by microRNAs (miRNAs) and RNA-binding proteins determines mRNA stability and translation rate and may override transcriptional cues in response to environmental changes, such as hypoxia. To identify distinct features of FLDM and BMDM response to hypoxia at the level of translation, we employed translating ribosome affinity purification (TRAP) to isolate polysomal RNA. RNA-seq profiling of translated RNA identified distinct hypoxia-induced translational signature of BMDM (Ly6e, vimentin and glycolysis-associated enzymes Pgk1, Tpi1, Aldoa, Ldha) and FLDM (chemokines Ccl7 and Ccl2). By translational profiling of BMDM and FLDM with deletion of the RNA-binding protein HuR, we identified transcripts that were dependent on HuR. These findings highlight the importance of HuR and identify its distinct targets for post-transcriptional regulation of gene expression in embryonic vs. adult-derived macrophages.


2021 ◽  
Author(s):  
Eun Seon Kim ◽  
Chang Geon Chung ◽  
Jeong Hyang Park ◽  
Byung Su Ko ◽  
Sung Soon Park ◽  
...  

Abstract RNA-binding proteins (RBPs) play essential roles in diverse cellular processes through post-transcriptional regulation of RNAs. The subcellular localization of RBPs is thus under tight control, the breakdown of which is associated with aberrant cytoplasmic accumulation of nuclear RBPs such as TDP-43 and FUS, well-known pathological markers for amyotrophic lateral sclerosis and frontotemporal dementia (ALS/FTD). Here, we report in Drosophila model for ALS/FTD that nuclear accumulation of a cytoplasmic RBP, Staufen, may be a new pathological feature. We found that in Drosophila C4da neurons expressing PR36, one of the arginine-rich dipeptide repeat proteins (DPRs), Staufen accumulated in the nucleus in Importin- and RNA-dependent manner. Notably, expressing Staufen with exogenous NLS—but not with mutated endogenous NLS—potentiated PR-induced dendritic defect, suggesting that nuclear-accumulated Staufen can enhance PR toxicity. PR36 expression increased Fibrillarin staining in the nucleolus, which was enhanced by heterozygous mutation of stau (stau+/−), a gene that codes Staufen. Furthermore, knockdown of fib, which codes Fibrillarin, exacerbated retinal degeneration mediated by PR toxicity, suggesting that increased amount of Fibrillarin by stau+/− is protective. Stau+/− also reduced the amount of PR-induced nuclear-accumulated Staufen and mitigated retinal degeneration and rescued viability of flies expressing PR36. Taken together, our data show that nuclear accumulation of Staufen in neurons may be an important pathological feature contributing to the pathogenesis of ALS/FTD.


2001 ◽  
Vol 356 (1415) ◽  
pp. 1755-1759 ◽  
Author(s):  
Dorothee Staiger

An Arabidopsis transcript preferentially expressed at the end of the daily light period codes for the RNA–binding protein At GRP7. A reverse genetic approach in Arabidopsis thaliana has revealed its role in the generation of circadian rhythmicity: At GRP7 is part of a negative feedback loop through which it influences the oscillations of its own transcript. Biochemical and genetic experiments indicate a mechanism for this autoregulatory circuit: At grp7 gene transcription is rhythmically activated by the circadian clock during the day. The At GPR7 protein accumulates with a certain delay and represses further accumulation of its transcript, presumably at the post–transcriptional level. In this respect, the At GRP7 feedback loop differs from known circadian oscillators in the fruitfly Drosophila and mammals based on oscillating clock proteins that repress transcription of their own genes with a 24 h rhythm. It is proposed that the At GRP7 feedback loop may act within an output pathway from the Arabidopsis clock.


1997 ◽  
Vol 17 (4) ◽  
pp. 2158-2165 ◽  
Author(s):  
A F Ross ◽  
Y Oleynikov ◽  
E H Kislauskis ◽  
K L Taneja ◽  
R H Singer

Localization of beta-actin mRNA to the leading edge of fibroblasts requires the presence of conserved elements in the 3' untranslated region of the mRNA, including a 54-nucleotide element which has been termed the "zipcode" (E. Kislauskis, X. Zhu, and R. H. Singer, J. Cell Biol. 127:441-451, 1994). In order to identify proteins which bind to the zipcode and possibly play a role in localization, we performed band-shift mobility assays, UV cross-linking, and affinity purification experiments. A protein of 68 kDa was identified which binds to the proximal (to the coding region) half of the zipcode with high specificity (ZBP-1). Microsequencing provided unique peptide sequences of approximately 15 residues each. Degenerate primers corresponding to the codons derived from the peptides were synthesized and used for PCR amplification. Screening of a chicken cDNA library resulted in isolation of several clones providing a DNA sequence encoding a 67.7-kDa protein with regions homologous to several RNA-binding proteins, such as hnRNP E1 and E2, and with consensus mRNA recognition motif with RNP1 and 2 motifs and a putative REV-like nuclear export signal. Antipeptide antibodies were raised in rabbits which bound to ZBP-1 and coimmunoprecipitated proteins of 120 and 25 kDa. The 120-kDa protein was also obtained by affinity purification with the RNA zipcode sequence, along with a 53-kDa protein, but the 25-kDa protein appeared only in immunoprecipitations. Mutation of one of the conserved sequences within the zipcode, an ACACCC element in its proximal half, greatly reduced its protein binding and localization properties. These data suggest that the 68-kDa ZBP-1 we have isolated and cloned is an RNA-binding protein that functions within a complex to localize beta-actin mRNA.


2018 ◽  
Author(s):  
Emad Bahrami-Samani ◽  
Yi Xing

AbstractGene expression is tightly regulated at the post-transcriptional level through splicing, transport, translation, and decay. RNA-binding proteins (RBPs) play key roles in post-transcriptional gene regulation, and genetic variants that alter RBP-RNA interactions can affect gene products and functions. We developed a computational method ASPRIN (Allele-Specific Protein-RNA Interaction), that uses a joint analysis of CLIP-seq (cross-linking and immunoprecipitation followed by high-throughput sequencing) and RNA-seq data to identify genetic variants that alter RBP-RNA interactions by directly observing the allelic preference of RBP from CLIP-seq experiments as compared to RNA-seq. We used ASPRIN to systematically analyze CLIP-seq and RNA-seq data for 166 RBPs in two ENCODE (Encyclopedia of DNA Elements) cell lines. ASPRIN identified genetic variants that alter RBP-RNA interactions by modifying RBP binding motifs within RNA. Moreover, through an integrative ASPRIN analysis with population-scale RNA-seq data, we showed that ASPRIN can help reveal potential causal variants that affect alternative splicing via allele-specific protein-RNA interactions.


Author(s):  
Masashi Yukawa ◽  
Mitsuki Ohishi ◽  
Yusuke Yamada ◽  
Takashi Toda

Cells form a bipolar spindle during mitosis to ensure accurate chromosome segregation. Proper spindle architecture is established by a set of kinesin motors and microtubule-associated proteins. In most eukaryotes, kinesin-5 motors are essential for this process, and genetic or chemical inhibition of their activity leads to the emergence of monopolar spindles and cell death. However, these deficiencies can be rescued by simultaneous inactivation of kinesin-14 motors, as they counteract kinesin-5. We conducted detailed genetic analyses in fission yeast to understand the mechanisms driving spindle assembly in the absence of kinesin-5. Here we show that deletion of the nrp1 gene, which encodes a putative RNA-binding protein with unknown function, can rescue temperature sensitivity caused by cut7-22, a fission yeast kinesin-5 mutant. Interestingly, kinesin-14/Klp2 levels on the spindles in the cut7 mutants were significantly reduced by the nrp1 deletion, although the total levels of Klp2 and the stability of spindle microtubules remained unaffected. Moreover, RNA-binding motifs of Nrp1 are essential for its cytoplasmic localization and function. We have also found that a portion of Nrp1 is spatially and functionally sequestered by chaperone-based protein aggregates upon mild heat stress and limits cell division at high temperatures. We propose that Nrp1 might be involved in post-transcriptional regulation through its RNA-binding ability to promote the loading of Klp2 on the spindle microtubules.


2021 ◽  
Author(s):  
Keisuke Hitachi ◽  
Yuri Kiyofuji ◽  
Masashi Nakatani ◽  
Kunihiro Tsuchida

RNA-binding proteins (RBPs) regulate cell physiology via the formation of ribonucleic-protein complexes with coding and non-coding RNAs. RBPs have multiple functions in the same cells; however, the precise mechanism through which their pleiotropic functions are determined remains unknown. In this study, we revealed the multiple inhibitory functions of hnRNPK for myogenic differentiation. We first identified hnRNPK as a lncRNA Myoparr binding protein. Gain- and loss-of-function experiments showed that hnRNPK repressed the expression of myogenin at the transcriptional level via binding to Myoparr. Moreover, hnRNPK repressed the expression of a set of genes coding for aminoacyl-tRNA synthetases in a Myoparr-independent manner. Mechanistically, hnRNPK regulated the eIF2α/Atf4 pathway, one branch of the intrinsic pathways of the endoplasmic reticulum sensors, in differentiating myoblasts. Thus, our findings demonstrate that hnRNPK plays multiple lncRNA-dependent and -independent roles in the inhibition of myogenic differentiation, indicating that the analysis of lncRNA-binding proteins will be useful for elucidating both the physiological functions of lncRNAs and the multiple functions of RBPs.


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