Riboswitches, as previously reported, are natural RNA aptamers that regulate the expression of numerous bacterial metabolic genes in response to small molecule ligands. It has recently been shown that these RNA genetic elements are also present near the splice site junctions of plant and fungal introns, thus raising the possibility of their involvement in regulating mRNA splicing. Here it is shown for the first time that a riboswitch can be engineered to regulate pre-mRNA splicing in vitro. We show that insertion of a high-affinity theophylline binding aptamer into the 3' splice site (3' ss) region of a model pre-mRNA (AdML-Theo29AG) enables its splicing to be repressed by the addition theophylline. Our results indicate that the location of 3' ss AG within the aptamer plays a crucial role in conferring theophylline-dependent control of pre-mRNA splicing. We also show that theophylline-mediated control of pre-mRNA splicing is highly specific by first demonstrating that a small molecule ligand similar in shape and size to theophylline had no effect on the splicing of AdML-Theo29AG pre-mRNA. Second, theophylline failed to exert any influence on the splicing of a pre-mRNA that does not contain its binding site. Third, theophylline specifically blocks the step II of the splicing reaction. Finally, we provide evidence that theophylline-dependent control of pre-mRNA splicing is functionally relevant.
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http://dx.doi.org/10.1261/rna.2162205 | DOI Listing |
Mol Cell
January 2025
Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, Irvine, CA 92697, USA. Electronic address:
Pre-mRNA 3' processing is an integral step in mRNA biogenesis. However, where this process occurs in the nucleus remains unknown. Here, we demonstrate that nuclear speckles (NSs), membraneless organelles enriched with splicing factors, are major sites for pre-mRNA 3' processing in human cells.
View Article and Find Full Text PDFRNA
December 2024
Instiute of Bioorganic Chemistry PAS
In this article, we present an approach to maximizing the splicing regulatory properties of splice-switching oligonucleotide (SSO) designed to regulate alternative splicing of PKM pre-mRNA. The studied SSO interacts with the regulatory element in exon 10 of PKM pre-mRNA and contributes to a significant reduction of PKM2 level with a simultaneous increase of the PKM1 isoform. This SSO forms a duplex not only with the regulatory fragment of exon 10 but also with a similar RNA fragment of intron 9.
View Article and Find Full Text PDFPlants (Basel)
December 2024
A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia.
Among the long non-coding RNAs that are currently recognized as important regulatory molecules influencing a plethora of processes in eukaryotic cells, circular RNAs (circRNAs) represent a distinct class of RNAs that are predominantly produced by back-splicing of pre-mRNA. The most studied regulatory mechanisms involving circRNAs are acting as miRNA sponges, forming R-loops with genomic DNA, and encoding functional proteins. In addition to circRNAs generated by back-splicing, two types of circRNAs capable of autonomous RNA-RNA replication and systemic transport have been described in plants: viroids, which are infectious RNAs that cause a number of plant diseases, and retrozymes, which are transcripts of retrotransposon genomic loci that are capable of circularization due to ribozymes.
View Article and Find Full Text PDFZhong Nan Da Xue Xue Bao Yi Xue Ban
July 2024
Southern Hospital affiliated with Shenzhen University, Shenzhen Guangdong 518001, China.
Triple-negative breast cancer (TNBC) is a highly aggressive breast cancer subtype with poor prognosis. RNA alternative splicing dysregulation plays a critical role in the initiation and progression of TNBC. This article systematically introduces the basic process of RNA splicing and then focuses on reviewing the aberrant alternative splicing events and their biological effects in TNBC: 1) Multiple splicing-related factors promote tumor cell proliferation and mediate chemotherapy resistance by regulating the alternative splicing of genes involved in cell survival and drug response; 2) dysregulation of splicing regulatory networks leads to altered splicing of multiple metastasis-related genes, promoting tumor invasion and metastasis; 3) aberrant alternative splicing events participate in tumor progression by affecting the expression of DNA damage repair genes; 4) dysregulation of alternative splicing is also involved in the regulation of tumor immune evasion and stem cell properties.
View Article and Find Full Text PDFHighly recurrent somatic mutations in the gene encoding the core splicing factor SF3B1 are drivers of multiple cancer types. SF3B1 is a scaffold protein that orchestrates multivalent protein-protein interactions within the spliceosome that are essential for recognizing the branchsite (BS) and selecting the 3' splice site during the earliest stage of pre-mRNA splicing. In this review, we first describe the molecular mechanism by which multiple oncogenic SF3B1 mutations disrupt splicing.
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