🧬 PubMed RNA Editing Daily Digest

This study investigates the regulatory role of microRNAs (miRNAs) in suppressing the overexpression of genes associated with Attention-Deficit Hyperactivity Disorder (ADHD), a genetically influenced neurodevelopmental disorder. A computational framework based on the 7mer-m8 seed match model was used to predict miRNA interactions with nine upregulated genes, aiming to identify miRNAs capable of binding to their coding sequences (CDS) and regulating gene expression. Coding sequences were retrieved from NCBI and analyzed for miRNA binding sites using established bioinformatics tools. Multiple miRNAs were found to target individual genes, including 36 for CHRNA4 and 17 for ADRA2C. Key parameters-such as GC and GC3 content, AMFE, COSM, translational frequency, RNA editing, mRNA stability, and ribosome residence time (RRT)-were assessed. Results indicated high GC (59.2 %) and GC3 (75.0 %) content at target regions, favoring miRNA binding. Notably, miR-4488 targeted the ADRA2C gene at two CDS positions (734-751 and 820-837). High RRT values (e.g., 1.17 for ADRA2C) and low compAI scores suggested slow translation and effective gene repression by miRNAs. The study concludes that specific miRNAs can bind within the CDS of overexpressed genes in ADHD, potentially suppressing their translation. These findings support the therapeutic potential of miRNAs in regulating gene expression in ADHD and lay the groundwork for future research on miRNA-based interventions in neurodevelopmental disorders.

CRISPR-Cas9 systems provide adaptive immunity in prokaryotes by targeting and cleaving invading phage DNA. In response, phages have evolved anti-CRISPR (Acr) proteins to inhibit Cas9 and evade this immune response. AcrIIA26 is a type II-A anti-CRISPR protein that inhibits Streptococcus pyogenes Cas9 (SpyCas9) DNA binding, but its molecular mechanism remains unclear. Here, we determined the 3.0 Å resolution cryo-EM structure of AcrIIA26 in complex with SpyCas9-single-guide RNA, revealing a dual inhibition mechanism. AcrIIA26 adopts a novel fold comprising a central β-sheet flanked by two α-helical bundles. The 5-helix bundle, which features a negatively charged surface whose shape mimics duplex DNA, occupies the same position as the protospacer adjacent motif (PAM) duplex in target-bound Cas9. This directly blocks PAM recognition by burying critical residues R1333 and R1335 in the PAM-interacting domain. Mutagenesis confirmed that residues E49 and D50 in AcrIIA26 are essential for this interaction. Simultaneously, the 4-helix bundle binds the Cas9 REC lobe and sterically prevents the conformational changes required for Cas9 activation, with mutation of AcrIIA26 F121 completely eliminating inhibitory activity. Structural comparisons reveal that despite diverse folds, multiple anti-CRISPRs convergently evolved to block PAM recognition, highlighting this as a critical vulnerability in Cas9 function. Our findings provide mechanistic insights into AcrIIA26 inhibition and offer a foundation for engineering improved Cas9 off-switches for genome editing applications.

Androgen deprivation therapies targeting the androgen receptor (AR) signaling pathway are the primary treatment strategy for prostate cancer. However, these therapies often lead to castration resistance. Developing novel agents targeting AR-independent oncogenes is critical to address this challenge, particularly for advanced castration-resistant prostate cancer. This study identified three potential tumor drivers of advanced prostate cancer, including CDC20, DTL, and RRM2, through integrative bioinformatic screening that considered gene dependency using CRISPRi/RNAi database, clinical relevance, and experimental validation with CRISPR-Cas13-mediated gene ablation. Further mechanistic studies revealed that CDC20, DTL, and RRM2 were transcriptionally regulated by the RB1/E2F1 axis, mediating cell cycle progression in prostate cancer. Additionally, we identified novel agents targeting these candidates through virtual screening and drug-sensitive tests, utilizing our established small-molecule library. These agents exhibited superior anti-tumor efficacy compared with AR antagonists

Cardiac hypertrophy represents a complex remodeling process involving extensive reprogramming of gene expression. While transcriptional regulation has been well characterized, post-transcriptional RNA processing has recently emerged as a crucial determinant of cardiac homeostasis. This review summarizes current knowledge of RNA modifications, alternative splicing, mRNA stability, and RNA editing in physiological and pathological hypertrophy. We highlight key epitranscriptomic marks such as N6-methyladenosine (m

Pulmonary Arterial Hypertension (PAH) is a rare vascular disorder characterized by elevated pressure in pulmonary arteries, eventually leading to right ventricular failure. Approximately 50% of pediatric disease and 20% of adult disease can be linked to a genetic mutation, with nearly 70% of these cases involving mutations in the bone morphogenetic protein receptor type 2 (BMPR2) locus. Investigations using rodent models have made significant advances in our understanding of BMPR2 signaling; however, limited data exist regarding the onset and course of PAH, and etiologies for phenotypic expression in these patients remain unknown. In this work, we describe the development of a novel ovine model of heritable PAH. Because homozygous disruption of BMPR2 is embryonic lethal, we developed heterozygous BMPR2 sheep by using a PAM-disrupting synonymous single stranded oligodeoxyribonucleotide alongside a single guide RNA and Cas9 mediated gene editing strategy. The resulting BMPR2(+/-) lambs demonstrated cardiac and pulmonary vascular pathology that are consistent with BMPR2 mutation-driven PAH observed in humans. Given the genetic and physiological similarities of BMPR2(+/-) sheep to humans with heritable PAH, this large animal model will serve as a vital platform for mechanistic molecular studies and will provide a much-needed pre-clinical model for extensive treatment evaluations.