Cytosine Base Editor N-terminal Fragment

N-terminal fragment of cytosine base editor split via Npu intein at E573. Requires C-terminal counterpart for reconstitution.

Length: 1000 bp (333 aa)

Type: Cytosine Base Editor

Conversion: C-to-T

Origin: Rat APOBEC1 fused to SpCas9 D10A nickase (amino acids 1-573)

Characteristics

Contains rat APOBEC1 cytosine deaminase domain and N-terminal portion of SpCas9 D10A (residues 1-573). Split site at E573 positions Npu intein for efficient protein trans-splicing. Expresses from Cbh promoter in reference AAV construct. No sgRNA cassette in N-terminal fragment.

Applications

Dual-delivery cytosine base editing systems requiring split architecture. Validated for AAV delivery to brain, liver, retina, heart, and skeletal muscle. Compatible with alternative delivery methods including lentivirus or electroporation when paired with C-terminal fragment.

Limitations

Non-functional without C-terminal pair. Reconstitution efficiency depends on expression levels, intein splicing kinetics, and delivery method. Must be co-delivered with split-cbe-ct for C-to-T editing activity.

Literature References

  1. Komor et al. (2016). Programmable editing of a target base in genomic DNA without double-stranded DNA cleavage. Nature - Komor 2016 BE3
  2. Levy et al. (2020). Cytosine and adenine base editing of the brain, liver, retina, heart and skeletal muscle of mice via adeno-associated viruses. Nat Biomed Eng - Levy 2020 BE3.9max