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BIO SEMINAR: CRISPR-Cas basic biology, types and its applications

Guest: Ahsen Özcan

Title: CRISPR-Cas basic biology, types and its applications

Date/Time: April 16, 2024, 15:00 - 16:00

Location: FENS G032(Hybrid)

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Meeting ID: 986 7768 5831
Passcode: 993310

Abstract:CRISPR–Cas interference is mediated by Cas effector nucleases that are either components of multisubunit complexes—in class 1 CRISPR–Cas systems—or domains of a single protein—in class 2 systems1,2,3. Here we show that the subtype III-E effector Cas7-11 is a single-protein effector in the class 1 CRISPR–Cas systems originating from the fusion of a putative Cas11 domain and multiple Cas7 subunits that are derived from subtype III-D. Cas7-11 from Desulfonema ishimotonii (DiCas7-11), when expressed in Escherichia coli, has substantial RNA interference effectivity against mRNAs and bacteriophages. Similar to many class 2 effectors—and unique among class 1 systems—DiCas7-11 processes pre-CRISPR RNA into mature CRISPR RNA (crRNA) and cleaves RNA at positions defined by the target:spacer duplex, without detectable non-specific activity. We engineered Cas7-11 for RNA knockdown and editing in mammalian cells. We show that Cas7-11 has no effects on cell viability, whereas other RNA-targeting tools (such as short hairpin RNAs and Cas13) show substantial cell toxicity4,5. This study illustrates the evolution of a single-protein effector from multisubunit class 1 effector complexes, expanding our understanding of the diversity of CRISPR systems. Cas7-11 provides the basis for new programmable RNA-targeting tools that are free of collateral activity and cell toxicity.

Bio: I obtained my Ph.D. in June 2019 from LMU München/Max Planck Institute for Terrestrial Microbiology. After obtaining a Ph.D. degree, I worked as a postdoctoral associate at the Massachusetts Institute of Technology for a year and characterized RNA targeting Cas7-11 protein.  Afterward, she joined the Beisel group at the Helmholtz Institute for RNA-based Infection Research and has been working on novel defense systems and CRISPR-Cas biology and applications. She obtained grants from DFG (German Research Council) and directed critical projects. After completion of her projects, she returned to Turkey as mandated by the Research Council of Turkey (TUBITAK) mandated by her PhD scholarship. Currently, she actively carries out CRISPR-Cas research at the Research Council of Turkey on the topic of CRISPR-Cas Biology and Genome Editing Field. 


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