Split-tracrRNA as an efficient tracrRNA system with an improved potential of scalability

Biomater Sci. 2023 May 2;11(9):3241-3251. doi: 10.1039/d2bm01901a.

Abstract

Due to the relatively long sequence, tracrRNAs are chemically less synthesizable than crRNAs, leading to limited scalability of RNA guides for CRISPR-Cas9 systems. To develop shortened versions of RNA guides with improved cost-effectiveness, we have developed a split-tracrRNA system by nicking the 67-mer tracrRNA (tracrRNA(67)). Cellular gene editing assays and in vitro DNA cleavage assays revealed that the position of the nick is critical for maintaining the activity of tracrRNA(67). TracrRNA(41 + 23), produced by nicking in stem loop 2, showed gene editing efficiency and specificity comparable to those of tracrRNA(67). Removal of the loop of stem loop 2 was further possible without compromising the efficiency and specificity when the stem duplex was stabilized via a high GC content. Binding assays and single-molecule experiments suggested that efficient split-tracrRNAs could be engineered as long as their binding affinity to Cas9 and their reaction kinetics are similar to those of tracrRNA(67).

MeSH terms

  • Gene Editing*
  • RNA / genetics
  • RNA, Guide, CRISPR-Cas Systems*

Substances

  • RNA, Guide, CRISPR-Cas Systems
  • RNA