RNA Interference (RNAi) PDF

RNA interference Discovery of RNA interference https://www.youtube.com/watch?v=Vh3-NHdjnyQ&t=9s Many genes have RNA products, not protein products transcription processing splicing DNA RNA...

RNA interference Discovery of RNA interference https://www.youtube.com/watch?v=Vh3-NHdjnyQ&t=9s Many genes have RNA products, not protein products transcription processing splicing DNA RNA mRNA protein tRNA (transfer RNA) Translation rRNA (ribosome RNA) RNA processing snRNA and snoRNA (small nuclear/nucleolar RNA) lncRNA (long noncoding RNA) miRNA (microRNA) Regulatory RNA Piwi-interacting RNA (piRNA) small interfering RNA (siRNA) short hairpin RNA (shRNA) miRNA and siRNA both function in gene regulation via RNAi https://en.wikipedia.org/wiki/RNA_interference How does RNA interference work? https://www.youtube.com/watch?v=5YsTW5i0Xro https://www.youtube.com/watch?v=cK-OGB1_ELE&t=23s How does RNA interference work? Quiz -- Canvas, Quizzes How does RNA interference work? miRNA- genomically encoded, single-stranded stem loop. ~20-25bp ~22nt siRNA- Exogenous dsRNA RNA-induced silencing Both RNA species complex function in the RNAi pathway. Add antisense RNA in plants Silencethe mRNA in plants. C complimentary to mRNA) Virus has UsRNA n Detence mechanism. Only Variation in different organisms It is a eukaryotic pathway. But it is not found in all eukaryotic organisms. Notable absence in budding yeast Saccharomyces cerevisiae, a powerful model organism. Notable expansion in plants. RNAi is heritable in plants, but not in mammals. In addition to gene regulation, RNAi functions as a defense mechanism against pathogens (a pathway that allows host cell to degrade pathogen mRNAs). RNA interference in prokaryotes? "Translational repression is sufficient for gene silencing by bacterial small noncoding RNAs in the absence of mRNA destruction". Proceedings of the National Academy of Sciences of the United States of America. 103 (13): 4858–63. Bacteria can be infected by viruses too-- CRISPR, an RNA-based mechanism comes to rescue! More in later part of the course… Achieving RNA interference with synthetic RNA Introducing synthesis dsRNA or pre- miRNA with sequence specific to the target mRNA. Achieving gene-specific degradation of target mRNA, and ‘knock-down’ of protein product. RNA-induced A useful research tool to silencing study protein functions in complex many model organisms.  Express Dicer d Argonaute in Yeast RNAI - Now Yeast can have Achieving RNA interference with synthetic RNA Notable absence in budding yeast Saccharomyces cerevisiae, a powerful model organism. Science 2009 Deploying RNA interference in biotechnology RNAi in plants have been used to-- Manage insects/pests and infections by viruses/bacteria; Improve crop quality; Improve tolerance to abiotic stresses; Create male sterility etc. Pros and cons? Pros : Does not Change the Gene KO is not reversible More in later part of the course… Cons : oFF farget Short tern EFFect RNA not SHable Hard to deliver Deploying RNA interference in therapeutics RNAi is a fundamental cellular mechanism for silencing gene expression that can be harnessed for the development of new drugs. The RNAi machinery (Dicer/Ago) is present in every human cells. Highly specific depletion of target mRNA/protein, without changing the genomic DNA sequence. Short development time (as compared to mAb or small chemical drugs). https://doi.org/10.1016/j.omtn.2023.07.018 Status of RNAi based therapies A total of 90 clinical trials were published 1998-2022. 48 on-going trials as of July 2023 (ClinicalTrials.gov). https://doi.org/10.1016/j.omtn.2023.07.018 6 RNAi-based medications have been approved in US and Europe: Patisiran, Givosiran, Lumasiran, Inclisiran, Vutrisiran and Rivfloza. As of 2021 10.1016/j.bcp.2021.114432 Challenges in designing RNAi therapy Challenges in designing RNAi therapy ~20-25bp ~22nt RNA-induced silencing complex  cells can stimulate RNA From proKargotic immune response Without Certain mocdification ,RNA will be treated as Foreign substances ,