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RU 1205

Type III CRISPR-Cas System to Modify Transcribed DNA

Since 2013, new tools based on CRISPR-associated protein-9 nuclease (Cas9) have allowed the development of efficient and reliable ways to make precise, targeted changes to the genome of living cells. However, to inactivate a gene of interest in a specific tissue and/or at a specific time point, other systems, like the Cre-lox system, need to be utilized. For the generation of mouse models, this involves rather complicated breeding (crossing the floxed strain with a Cre transgenic line) such that the target gene becomes inactivated in vivo.

Dr. Marraffini and colleagues have developed a new tool based on type III-A CRISPR-Cas technology that only targets DNA that is being transcribed. Similar to the Cas9 system, this technology includes a guide RNA targeted to a DNA sequence, but also the type III Cas proteins. The method functions such that the Cas proteins cleave the target sequence only during the transcription of the DNA. Thus, this new tool would allow conditional deletion of genes without the need of other systems and would streamline the process of making time-consuming crosses between different strains of mice.


  • Only targets transcribed DNA
  • Potentially used to generate conditional deletion of genes

Area of Application

Gene editing

Stage of Development

Available for licensing

Lead Inventor

Drs. Luciano A. Marraffini, Gregory Goldberg, Poulami Samai

Patent Information and References

  • Patent application filed

For Further Information