Point mutations, deletions, and a sequence context change were introduced at positions 3' to the internal conserved TACTAAC sequence of the Saccharomyces cerevisiae actin intron. In vivo analysis of yeast mRNA splicing suggests that, in contrast to the importance of the polypyrimidine tract in metazoan introns, specific sequences in this region are not required for efficient excision of a yeast intron. However, a double point mutation near the 3' junction (GG/AC) does severely inhibit splicing. Although this mutagenesis of the 3' junction, as well as deletion of most nucleotides between the TACTAAC and the 3' junction, caused only a slight accumulation of primary transcript, the observed accumulation of lariat intermediate by these mutants demonstrates the significance of this region for a step(s) in the splicing process after lariat formation.
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http://dx.doi.org/10.1128/mcb.7.1.225-230.1987 | DOI Listing |
Genomics Proteomics Bioinformatics
January 2025
Center for Epigenetics and Disease Prevention, Institute of Biosciences and Technology, Texas A&M University, Houston, TX 77030, USA.
Tumor-specific antigens, also known as neoantigens, have potential utility in anti-cancer immunotherapy, including immune checkpoint blockade (ICB), neoantigen-specific T cell receptor-engineered T (TCR-T), chimeric antigen receptor T (CAR-T), and therapeutic cancer vaccines (TCVs). After recognizing presented neoantigens, the immune system becomes activated and triggers the death of tumor cells. Neoantigens may be derived from multiple origins, including somatic mutations (single nucleotide variants, insertion/deletions, and gene fusions), circular RNAs, alternative splicing, RNA editing, and polymorphic microbiome.
View Article and Find Full Text PDFNucleic Acids Res
January 2025
Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, 620 West Chang'an Avenue, Chang'an District, Xi'an, Shaanxi 710119, P.R. China.
We present a robust 'splice-at-will' CRISPR RNA (crRNA) engineering mechanism that overcomes the limitations of clustered regularly interspaced short palindromic repeats (CRISPR)/Cas system in directly detecting ultrashort RNAs. In this strategy, an intact Cas12a crRNA can be split from almost any site of the spacer region to obtain a truncated crRNA (tcrRNA) that cannot activate Cas12a even after binding an auxiliary DNA activator. While splicing tcrRNAs with a moiety of ultrashort RNA, the formed combination can work together to activate Cas12a efficiently, enabling 'splice-at-will' crRNA engineering.
View Article and Find Full Text PDFNucleic Acids Res
January 2025
Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa, Chiba 277-8562, Japan.
U6 snRNA (small nuclear ribonucleic acid) is a ribozyme that catalyzes pre-messenger RNA (pre-mRNA) splicing and undergoes epitranscriptomic modifications. After transcription, the 3'-end of U6 snRNA is oligo-uridylylated by the multi-domain terminal uridylyltransferase (TUTase), TUT1. The 3'- oligo-uridylylated tail of U6 snRNA is crucial for U4/U6 di-snRNP (small nuclear ribonucleoprotein) formation and pre-mRNA splicing.
View Article and Find Full Text PDFJ Thorac Dis
December 2024
Department of Urology, Guangdong Provincial Key Laboratory of Urology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
Background: Tyrosine kinase inhibitors (TKIs) are the first-line therapy for patients with non-small cell lung cancer (NSCLC) with sensitized mutations in the epidermal growth factor receptor (). However, resistance to TKIs is a major clinical issue that affects the survival and prognosis of the patients, with the mechanisms underlying this resistance remaining elusive. Circular RNAs (circRNAs) are a class of single-stranded, covalently closed RNA molecules, which are generated from pre-messenger RNAs (mRNAs) through back splicing.
View Article and Find Full Text PDFThe U4 small nuclear RNA (snRNA) forms a duplex with the U6 snRNA and, together with U5 and ∼30 proteins, is part of the U4/U6.U5 tri-snRNP complex, located at the core of the major spliceosome. Recently, recurrent variants in the U4 RNA, transcribed from the gene, and in at least two other genes were discovered to cause neurodevelopmental disorder.
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