scholarly journals Molecular Mechanisms and Future Therapeutics for Spinocerebellar Ataxia Type 31 (SCA31)

2019 ◽  
Vol 16 (4) ◽  
pp. 1106-1114 ◽  
Author(s):  
Kinya Ishikawa ◽  
Yoshitaka Nagai

AbstractSpinocerebellar ataxia type 31 (SCA31) is one of the autosomal-dominant neurodegenerative disorders that shows progressive cerebellar ataxia as a cardinal symptom. This disease is caused by a 2.5- to 3.8-kb-long complex pentanucleotide repeat containing (TGGAA)n, (TAGAA)n, (TAAAA)n, and (TAAAATAGAA)n in an intron of the gene called BEAN1 (brain expressed, associated with Nedd4). By comparing various pentanucleotide repeats in this particular locus among control Japanese and Caucasian populations, it was found that (TGGAA)n was the only sequence segregating with SCA31, strongly suggesting the pathogenicity of (TGGAA)n. The complex repeat also lies in an intron of another gene, TK2 (thymidine kinase 2), which is transcribed in the opposite direction, indicating that the complex repeat is bi-directionally transcribed as noncoding repeats. In SCA31 human brains, (UGGAA)n, the BEAN1 transcript of SCA31 mutation was found to form abnormal RNA structures called RNA foci in cerebellar Purkinje cell nuclei. Subsequent RNA pulldown analysis disclosed that (UGGAA)n binds to RNA-binding proteins TDP-43, FUS, and hnRNP A2/B1. In fact, TDP-43 was found to co-localize with RNA foci in human SCA31 Purkinje cells. To dissect the pathogenesis of (UGGAA)n in SCA31, we generated transgenic fly models of SCA31 by overexpressing SCA31 complex pentanucleotide repeats in Drosophila. We found that the toxicity of (UGGAA)n is length- and expression level–dependent, and it was dampened by co-expressing TDP-43, FUS, and hnRNP A2/B1. Further investigation revealed that TDP-43 ameliorates (UGGAA)n toxicity by directly fixing the abnormal structure of (UGGAA)n. This led us to propose that TDP-43 acts as an RNA chaperone against toxic (UGGAA)n. Further research on the role of RNA-binding proteins as RNA chaperones may provide a novel therapeutic strategy for SCA31.

2021 ◽  
Vol 15 ◽  
Author(s):  
Taro Ishiguro ◽  
Yoshitaka Nagai ◽  
Kinya Ishikawa

Spinocerebellar ataxia type 31 (SCA31) is a progressive neurodegenerative disease characterized by degeneration of Purkinje cells in the cerebellum. Its genetic cause is a 2.5- to 3.8-kb-long complex pentanucleotide repeat insertion containing (TGGAA)n, (TAGAA)n, (TAAAA)n, and (TAAAATAGAA)n located in an intron shared by two different genes: brain expressed associated with NEDD4-1 (BEAN1) and thymidine kinase 2 (TK2). Among these repeat sequences, (TGGAA)n repeat was the only sequence segregating with SCA31, which strongly suggests its pathogenicity. In SCA31 patient brains, the mutant BEAN1 transcript containing expanded UGGAA repeats (UGGAAexp) was found to form abnormal RNA structures called RNA foci in cerebellar Purkinje cell nuclei. In addition, the deposition of pentapeptide repeat (PPR) proteins, poly(Trp-Asn-Gly-Met-Glu), translated from UGGAAexp RNA, was detected in the cytoplasm of Purkinje cells. To uncover the pathogenesis of UGGAAexp in SCA31, we generated Drosophila models of SCA31 expressing UGGAAexp RNA. The toxicity of UGGAAexp depended on its length and expression level, which was accompanied by the accumulation of RNA foci and translation of repeat-associated PPR proteins in Drosophila, consistent with the observation in SCA31 patient brains. We also revealed that TDP-43, FUS, and hnRNPA2B1, motor neuron disease–linked RNA-binding proteins bound to UGGAAexp RNA, act as RNA chaperones to regulate the formation of RNA foci and repeat-associated translation. Further research on the role of RNA-binding proteins as RNA chaperones may also provide a novel therapeutic strategy for other microsatellite repeat expansion diseases besides SCA31.


Author(s):  
Nicole J. Curtis ◽  
Constance J. Jeffery

RNA binding proteins play key roles in many aspects of RNA metabolism and function, including splicing, transport, translation, localization, stability and degradation. Within the past few years, proteomics studies have identified dozens of enzymes in intermediary metabolism that bind to RNA. The wide occurrence and conservation of RNA binding ability across distant branches of the evolutionary tree suggest that these moonlighting enzymes are involved in connections between intermediary metabolism and gene expression that comprise far more extensive regulatory networks than previously thought. There are many outstanding questions about the molecular structures and mechanisms involved, the effects of these interactions on enzyme and RNA functions, and the factors that regulate the interactions. The effects on RNA function are likely to be wider than regulation of translation, and some enzyme–RNA interactions have been found to regulate the enzyme's catalytic activity. Several enzyme–RNA interactions have been shown to be affected by cellular factors that change under different intracellular and environmental conditions, including concentrations of substrates and cofactors. Understanding the molecular mechanisms involved in the interactions between the enzymes and RNA, the factors involved in regulation, and the effects of the enzyme–RNA interactions on both the enzyme and RNA functions will lead to a better understanding of the role of the many newly identified enzyme–RNA interactions in connecting intermediary metabolism and gene expression.


2020 ◽  
Vol 21 (20) ◽  
pp. 7803
Author(s):  
Julie Miro ◽  
Anne-Laure Bougé ◽  
Eva Murauer ◽  
Emmanuelle Beyne ◽  
Dylan Da Cunha ◽  
...  

The Duchenne muscular dystrophy (DMD) gene has a complex expression pattern regulated by multiple tissue-specific promoters and by alternative splicing (AS) of the resulting transcripts. Here, we used an RNAi-based approach coupled with DMD-targeted RNA-seq to identify RNA-binding proteins (RBPs) that regulate splicing of its skeletal muscle isoform (Dp427m) in a human muscular cell line. A total of 16 RBPs comprising the major regulators of muscle-specific splicing events were tested. We show that distinct combinations of RBPs maintain the correct inclusion in the Dp427m of exons that undergo spatio-temporal AS in other dystrophin isoforms. In particular, our findings revealed the complex networks of RBPs contributing to the splicing of the two short DMD exons 71 and 78, the inclusion of exon 78 in the adult Dp427m isoform being crucial for muscle function. Among the RBPs tested, QKI and DDX5/DDX17 proteins are important determinants of DMD exon inclusion. This is the first large-scale study to determine which RBP proteins act on the physiological splicing of the DMD gene. Our data shed light on molecular mechanisms contributing to the expression of the different dystrophin isoforms, which could be influenced by a change in the function or expression level of the identified RBPs.


2019 ◽  
Vol 20 (16) ◽  
pp. 3926 ◽  
Author(s):  
Xing Zhao ◽  
Yujie Cai ◽  
Jianzhen Xu

CircRNAs are a class of noncoding RNA species with a circular configuration that is formed by either typical spliceosome-mediated or lariat-type splicing. The expression of circRNAs is usually abnormal in many cancers. Several circRNAs have been demonstrated to play important roles in carcinogenesis. In this review, we will first provide an introduction of circRNAs biogenesis, especially the regulation of circRNA by RNA-binding proteins, then we will focus on the recent findings of circRNA molecular mechanisms and functions in cancer development. Finally, some open questions are also discussed.


2021 ◽  
Author(s):  
Matteo D'Antonio ◽  
Jennifer P. Nguyen ◽  
Timothy D. Arthur ◽  
Hiroko Matsui ◽  
Margaret K.R. Donovan ◽  
...  

Transcriptome-wide expression changes occur during heart failure, including reactivation of fetal-specific isoforms. However, the underlying molecular mechanisms and the extent to which a fetal gene program switch occurs remains unclear. Limitations hindering transcriptome-wide analyses of alternative splicing differences (i.e. isoform switching) in cardiovascular system (CVS) tissues between fetal and adult (healthy and diseased) stages have included both cellular heterogeneity across bulk RNA-seq samples and limited availability of fetal tissue for research. To overcome these limitations, we have deconvoluted the cellular compositions of 996 RNA-seq samples representing heart failure, healthy adult (heart and arteria), and fetal-like (iPSC-derived cardiovascular progenitor cells) CVS tissues. Comparison of the expression profiles revealed that RNA-binding proteins (RBPs) are highly overexpressed in fetal-like compared with healthy adult and are reactivated in heart failure, which results in expression of thousands fetal-specific isoforms. Of note, isoforms for 20 different RBPs were among those that reverted in heart failure to the fetal-like expression pattern. We determined that, compared with adult-specific isoforms, fetal-specific isoforms are more likely to bind RBPs, have canonical sequences at their splice sites and encode proteins with more functions. Our findings suggest targeting RBP fetal-specific isoforms could result in novel therapeutics for heart failure.


Biomolecules ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 591 ◽  
Author(s):  
Daria Mordovkina ◽  
Dmitry N. Lyabin ◽  
Egor A. Smolin ◽  
Ekaterina M. Sogorina ◽  
Lev P. Ovchinnikov ◽  
...  

Y-box binding proteins (YB proteins) are DNA/RNA-binding proteins belonging to a large family of proteins with the cold shock domain. Functionally, these proteins are known to be the most diverse, although the literature hardly offers any molecular mechanisms governing their activities in the cell, tissue, or the whole organism. This review describes the involvement of YB proteins in RNA-dependent processes, such as mRNA packaging into mRNPs, mRNA translation, and mRNA stabilization. In addition, recent data on the structural peculiarities of YB proteins underlying their interactions with nucleic acids are discussed.


2021 ◽  
Vol 8 ◽  
Author(s):  
Yuanyuan Ding ◽  
Ruihua Yin ◽  
Shuai Zhang ◽  
Qi Xiao ◽  
Hongqin Zhao ◽  
...  

Atherosclerosis is a complex disease closely related to the function of endothelial cells (ECs), monocytes/macrophages, and vascular smooth muscle cells (VSMCs). Despite a good understanding of the pathogenesis of atherosclerosis, the underlying molecular mechanisms are still only poorly understood. Therefore, atherosclerosis continues to be an important clinical issue worthy of further research. Recent evidence has shown that long non-coding RNAs (lncRNAs) and RNA-binding proteins (RBPs) can serve as important regulators of cellular function in atherosclerosis. Besides, several studies have shown that lncRNAs are partly dependent on the specific interaction with RBPs to exert their function. This review summarizes the important contributions of lncRNAs and RBPs in atherosclerosis and provides novel and comprehensible interaction models of lncRNAs and RBPs.


2021 ◽  
Author(s):  
Xinyu Lu ◽  
Zitong Yang ◽  
Wen Song ◽  
Jierui Si ◽  
Zhiyuan Yin ◽  
...  

AbstractOomycete pathogens secrete many effectors to manipulate plant immunity and promote infection. However, relatively few effector types have been well characterized. In this study, members of a FYVE domain-containing protein family that is highly expanded in oomycetes were systematically identified, and one secreted protein, PsFYVE1, was selected for further study. PsFYVE1 enhanced Phytophthora infection in Nicotiana benthamiana and was necessary for P. sojae virulence. The FYVE domain of PsFYVE1 had PI3P-binding activity that depended on four conservative amino acid residues. Furthermore, PsFYVE1 targeted RNA-binding proteins RZ-1A/1B/1C in N. benthamiana and soybean, and silencing of NbRZ-1A/1B/1C genes attenuates plant immunity. NbRZ-1A was associated with spliceosome that included three important components, NbGRP7, NbGRP8, and NbU1-70K. Notably, PsFYVE1 could disrupt NbRZ-1A–NbGRP7 interaction. RNA-seq and subsequent experimental analysis demonstrated that PsFYVE1 and NbRZ-1A not only co-regulated transcription of NbHCT, NbEIN2, and NbSUS4 genes but also modulated pre-mRNA alternative splicing (AS) of the NbNSL1 gene, which participated in plant immunity. Collectively, these findings indicate that the FYVE domain-containing protein family includes potential new effector types and also highlight that plant pathogen effectors can regulate plant immunity related genes at both transcription and AS levels to promote disease.Author summaryMany plant pathogenic oomycetes secrete effector proteins into plants to facilitate infection. Discovering potential repertoire of novel effectors and corresponding molecular mechanisms are major themes in the study of oomycete–plant interactions. Here, we characterized a FYVE domain-containing protein (PsFYVE1) in P. sojae. PsFYVE1 carries a functional secretory signal peptide and is a virulence-essential effector for P. sojae infection. We demonstrated that PsFYVE1 interacted with a class of plant RNA-binding proteins, including soybean GmRZ-1A/1B/1C and N. benthamiana NbRZ-1A/1B/1C. Silencing of NbRZ-1A/1B/1C proteins increased Phytophthora infection and suppressed plant defense. Furthermore, NbRZ-1A interacted with the spliceosome components, and PsFYVE1 disrupted association between NbRZ-1A and spliceosome component NbGRP7. We examined the global transcription and alternative splicing (AS) changes regulated by PsFYVE1 and NbRZ-1A, which indicated that PsFYVE1 and NbRZ-1A co-regulated transcription and pre-mRNA AS of immunity-related genes. Thus, this study identifies a novel virulence-related effector from P. sojae and a class of positive regulators of plant immunity, and reveals a detailed mechanism of effector-medicated transcription and AS regulation during pathogen–plant interactions.


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