Part:BBa_K5490009

Scaffold or direct repeat region (DR 30)

gRNAs (guide RNAs) are relatively small RNA molecules that play a crucial role in gene editing and RNA-targeting technologies. They are typically expressed under the control of a promoter, often polymerase III, which is ideal given the high complexity of the gRNA's secondary structure. These gRNAs are composed of two main components:

The scaffold or direct repeat region: This region forms a complex secondary structure after transcription, allowing it to bind effectively to an effector molecule such as CasRx, which acts as an RNA nuclease, specifically targeting single-stranded RNA. There are two types of direct repeat sequences commonly used--one that is 30 nucleotides long and another that is 36 nucleotides long. The 36-nucleotide direct repeat has been shown to have a higher affinity for CasRx, improving the overall efficiency of the RNA-targeting system.

By integrating both the scaffold and spacer, researchers can achieve precise RNA cleavage

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  COMPATIBLE WITH RFC[1000]

Source

Konermann S, Lotfy P, Brideau NJ, Oki J, Shokhirev MN, Hsu PD. Transcriptome Engineering with RNA-Targeting Type VI-D CRISPR Effectors. Cell. 2018 Apr 19;173(3):665-676.e14. doi: 10.1016/j.cell.2018.02.033. Epub 2018 Mar 15. PMID: 29551272; PMCID: PMC5910255.

Vad-Nielsen J, Lin L, Bolund L, Nielsen AL, Luo Y. Golden Gate Assembly of CRISPR gRNA expression array for simultaneously targeting multiple genes. Cell Mol Life Sci. 2016 Nov;73(22):4315-4325. doi: 10.1007/s00018-016-2271-5. Epub 2016 May 13. PMID: 27178736; PMCID: PMC11108369.

Chuang YF, Wang PY, Kumar S, Lama S, Lin FL, Liu GS. Methods for in vitro CRISPR/CasRx-Mediated RNA Editing. Front Cell Dev Biol. 2021 Jun 11;9:667879. doi: 10.3389/fcell.2021.667879. PMID: 34178991; PMCID: PMC8226256.