Base-Editor-Mediated circRNA Knockout by Targeting Predominantly Back-Splice Sites.

Back-splicing of eukaryotic exon(s) leads to the production of covalently closed circular RNAs (circRNAs). Generally, most circRNAs contain overlapping sequences to their cognate linear RNAs from the same gene loci, leading to difficulties in distinguishing them from each other. A recent study has shown that some circRNAs can be specifically depleted by using base editing systems to target their predominantly back-splice sites for circularization, suggesting an efficient approach for circRNA knockout (KO).

IntS6 and the Integrator phosphatase module tune the efficiency of select premature transcription termination events.

The metazoan-specific Integrator complex catalyzes 3' end processing of small nuclear RNAs (snRNAs) and premature termination that attenuates the transcription of many protein-coding genes. Integrator has RNA endonuclease and protein phosphatase activities, but it remains unclear if both are required for complex function. Here, we show IntS6 (Integrator subunit 6) over-expression blocks Integrator function at a subset of Drosophila protein-coding genes, although having no effect on snRNAs or attenuation of other loci.

Approaches and challenges in genome-wide circular RNA identification and quantification.

Numerous circular RNAs (circRNAs) produced from back-splicing of exon(s) have been recently revealed on a genome-wide scale across species. Although generally expressed at a low level, some relatively abundant circRNAs can play regulatory roles in various biological processes, prompting continuous profiling of circRNA in broader conditions. Over the past decade, distinct strategies have been applied in both transcriptome enrichment and bioinformatic tools for detecting and quantifying circRNAs.

[Correlation between 25-hydroxyvitamin D and nephroblastoma in children and its value in assessing disease prognosis].

Objectives: To study the correlation between 25-hydroxyvitamin D [25-(OH)D] and nephroblastoma in children and its value in assessing the prognosis of the disease.

Methods: A total of 50 children with nephroblastoma who were admitted from January 2018 to December 2022 were included as the nephroblastoma group, and according to the postoperative pathological type, they were divided into a good prognosis group with 38 children and a poor prognosis group with 12 children. A total of 50 healthy children who underwent physical examination during the same period of time served as the healthy control group.

CRISPR-dCas13-tracing reveals transcriptional memory and limited mRNA export in developing zebrafish embryos.

Background: Understanding gene transcription and mRNA-protein (mRNP) dynamics in single cells in a multicellular organism has been challenging. The catalytically dead CRISPR-Cas13 (dCas13) system has been used to visualize RNAs in live cells without genetic manipulation. We optimize this system to track developmentally expressed mRNAs in zebrafish embryos and to understand features of endogenous transcription kinetics and mRNP export.

CIRCexplorer pipelines for circRNA annotation and quantification from non-polyadenylated RNA-seq datasets.

Covalently closed circular RNAs (circRNAs) produced by back-splicing of exon(s) are co-expressed with their cognate linear RNAs from the same gene loci. Most circRNAs are fully overlapped with their cognate linear RNAs in sequences except the back-spliced junction (BSJ) site, thus challenging the computational detection, experimental validation and hence functional evaluation of circRNAs. Nevertheless, specific bioinformatic pipelines were developed to identify fragments mapped to circRNA-featured BSJ sites, and circRNAs were pervasively identified from non-polyadenylated RNA-seq datasets in different cell lines/tissues and across species.

Fast and furious: insights of back splicing regulation during nascent RNA synthesis.

Alternative splicing of eukaryotic precursor (messenger) RNAs in the nucleus not only increases transcriptomic complexity, but also expands proteomic and functional diversity. In addition to basic types of alternative splicing, recent transcriptome-wide analyses have also suggested other new types of non-canonical splicing, such as back splicing and recursive splicing, and their widespread expression across species Increasing lines of evidence have suggested mechanisms for back splicing, including insights from analyses of nascent RNA sequencing. In this review, we discuss our current understanding of back splicing regulation, and highlight its distinct characteristics in processing during nascent RNA synthesis by taking advantage of metabolic tagging nascent RNA sequencing.

Distinct Processing of lncRNAs Contributes to Non-conserved Functions in Stem Cells.

Long noncoding RNAs (lncRNAs) evolve more rapidly than mRNAs. Whether conserved lncRNAs undergo conserved processing, localization, and function remains unexplored. We report differing subcellular localization of lncRNAs in human and mouse embryonic stem cells (ESCs).

CIRCexplorer3: A CLEAR Pipeline for Direct Comparison of Circular and Linear RNA Expression.

Sequences of circular RNAs (circRNAs) produced from back-splicing of exon(s) completely overlap with those from cognate linear RNAs transcribed from the same gene loci with the exception of their back-splicing junction (BSJ) sites. Therefore, examination of global circRNA expression from RNA-seq datasets generally relies on the detection of RNA-seq fragments spanning BSJ sites, which is different from the quantification of linear RNA expression by normalized RNA-seq fragments mapped to whole gene bodies. Thus, direct comparison of circular and linear RNA expression from the same gene loci in a genome-wide manner has remained challenging.

Circular RNAs negatively regulate cancer stem cells by physically binding FMRP against CCAR1 complex in hepatocellular carcinoma.

Circular RNA (circRNA) possesses great pre-clinical diagnostic and therapeutic potentials in multiple cancers. It has been reported playing roles in multiple malignant behaviors including proliferation, migration, metastasis and chemoresistance. However, the underlying correlation between circRNAs and cancer stem cells (CSCs) has not been reported yet.

CIRCpedia v2: An Updated Database for Comprehensive Circular RNA Annotation and Expression Comparison.

Circular RNAs (circRNAs) from back-splicing of exon(s) have been recently identified to be broadly expressed in eukaryotes, in tissue- and species-specific manners. Although functions of most circRNAs remain elusive, some circRNAs are shown to be functional in gene expression regulation and potentially relate to diseases. Due to their stability, circRNAs can also be used as biomarkers for diagnosis.

Increased complexity of circRNA expression during species evolution.

Circular RNAs (circRNAs) are broadly identified from precursor mRNA (pre-mRNA) back-splicing across various species. Recent studies have suggested a cell-/tissue- specific manner of circRNA expression. However, the distinct expression pattern of circRNAs among species and its underlying mechanism still remain to be explored.