Analyzing the process of mutation accumulation in KRAS evolution experiment using amplicon sequencing
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ABSTRACT: Directed evolution in mammalian cells can facilitate the engineering of mammalian-compatible biomolecules and can enable synthetic evolvability for mammalian cells. We engineered an orthogonal alphaviral RNA replication system to evolve synthetic RNA-based devices, enabling RNA replicase-assisted continuous evolution (REPLACE) in live mammalian cells. Using REPLACE, we attempted continuous intracellular evolution of the negative dominant mutant KRAS (S17N). To analyze the process of mutation accumulation, we performed amplicon sequencing on experimental materials at different stages and under different treatment conditions. The results indicated that the mutations generated by this system were primarily induced by Monanunavir, and the addition of Monanunavir significantly accelerated the rate of evolution.
Project description:Directed evolution in mammalian cells can facilitate the engineering of mammalian-compatible biomolecules and can enable synthetic evolvability for mammalian cells. We engineered an orthogonal alphaviral RNA replication system to evolve synthetic RNA-based devices, enabling RNA replicase-assisted continuous evolution (REPLACE) in live mammalian cells. we employed REPLACE to drive the continuous intracellular evolution of the cancer-related protein MEK1 with the aim of conferring resistance to Cobimetinib. To investigate the accumulation of mutations during this evolutionary process, we conducted amplicon sequencing on experimental materials collected at different stages. The results revealed intricate relationships among different mutations, highlighting the complex nature of the evolutionary landscape.
Project description:Directed evolution in mammalian cells can facilitate the engineering of mammalian-compatible biomolecules and can enable synthetic evolvability for mammalian cells. We engineered an orthogonal alphaviral RNA replication system to evolve synthetic RNA-based devices, enabling RNA replicase-assisted continuous evolution (REPLACE) in live mammalian cells. Toinvestigatetheexpressionheterogeneityofself-replicatingRNAsinrepRNA-v4cells,weperformedsingle-cellRNA-seqanalysisusingthe10xGenomicssequencingmethod.Ouranalysisofthesingle-cellRNA-seqprofilingdatarevealedarelativelyuniformexpressionpatternofself-replicatingRNAswithinrepRNA-v4cells.
Project description:Directed evolution in mammalian cells can facilitate the engineering of mammalian-compatible biomolecules and can enable synthetic evolvability for mammalian cells. We engineered an orthogonal alphaviral RNA replication system to evolve synthetic RNA-based devices, enabling RNA replicase-assisted continuous evolution (REPLACE) in live mammalian cells. To determine the degradation rate of alphaviral RNA in BHK-21 cells, 10 µg of repRNA-v4 RNA was transfected into 4 million wildtype BHK-21 cells via electroporation. Samples were collected at 1-hour, 3-hour, and 12-hour time points for subsequent RNA-seq analysis. The findings revealed that the half-life of alphaviral RNA in the cells was approximately 3.5 hours.
Project description:Directed evolution in mammalian cells can facilitate the engineering of mammalian-compatible biomolecules and can enable synthetic evolvability for mammalian cells. We engineered an orthogonal alphaviral RNA replication system to evolve synthetic RNA-based devices, enabling RNA replicase-assisted continuous evolution (REPLACE) in live mammalian cells. RNA-seq of 3 different cells was performed to analyze the effect of introducing different versions of RNA replication systems (i.e., repRNA-v3 and repRNA-v4) into BHK-21 cells on endogenous gene expression. Analysis of the transcriptome profiling data indicated that repRNA-v4 stimulated lower interferon signaling and may have lower cytopathicity.
Project description:Directed evolution in mammalian cells can facilitate the engineering of mammalian-compatible biomolecules and can enable synthetic evolvability for mammalian cells. We engineered an orthogonal alphaviral RNA replication system to evolve synthetic RNA-based devices, enabling RNA replicase-assisted continuous evolution (REPLACE) in live mammalian cells. To investigate the process of mutation accumulation in REPLACE system, we constructed a repRNA-v4 plasmid library containing 64 barcodes. Using this library, we analyzed the differences in mutation accumulation for different RNAs upon entry into cells, before and after molnupiravir treatment, and before and after FACS sorting. The results demonstrated that these barcoded RNAs undergo similar processes of mutation accumulation, providing evidence that mutations are commonly accumulated across different RNAs.
Project description:REPLACE was engineered from an orthogonal alphaviral RNA replication system. It generates a large, continuously diversified library of replicative RNAs through a replicase-limited mode of replication and inducible mutagenesis. We analyzed the variation of RNA mutations induced by two nucleoside analogues over time and at different concentrations. This data was used to guide the construction of RNA mutant libraries.
Project description:REPLACE was engineered from an orthogonal alphaviral RNA replication system. It generates a large, continuously diversified library of replicative RNAs through a replicase-limited mode of replication and inducible mutagenesis. We analyzed the mutation frequency at Day0 (IVT RNA), Day1, Day3, Day7, Day14, Day21 and DNA plasmid to estimate the RNA mutation rate. This data was used to guide the construction of RNA mutant libraries.
Project description:Drug resistance poses a significant clinical challenge, and comprehending the mechanisms underlying this resistance can facilitate the design of novel inhibitors and advance cancer treatment. The REPLACE system was employed to examine resistance mutations in MEK1 during the administration of 3 allosteric inhibitors (i.e., cobimetinib, trametinib, and selumetinib). These experiments represent a category of experiments that utilize REPLACE to achieve continuous evolution (or adaptation) by linking the activity of evolutionary targets with the survival of mammalian cells.
Project description:Transcriptional regulators are fundamental elements in synthetic biology. We sought to use REPLACE to evolve synthetic transcriptional regulators. Through weeks of directed evolution experiments, we succesufuly modified the sensitivity of TetR and PadR to ligand molecules.
Project description:A dominant-negative gene therapy approach has been proposed and tested on proto-oncogene KRAS, wherein the oncogenic activity (and cell proliferation) of KRAS can be suppressed by introducing a dominant-negative KRAS allele (S17N). We employed REPLACE to conduct continuous evolution on KRAS (S17N) and examined its potential pathways for conferring resistance in this gene therapy methodology.