Ultracompact precision editing systems and uses thereof

A composition for modifying a nucleobase of a target nucleic acid, the system comprising:

• a. an effector protein, or a nucleic acid encoding the effector protein, wherein the effector protein comprises an amino acid sequence that is at least 90% identical to SEQ ID NO:
• 1;
• b. a base editing enzyme, or a nucleic acid encoding the base editing enzyme;
• and
• c. a guide RNA or a nucleic acid that encodes the guide RNA, wherein the guide RNA comprises a first region that interacts with the effector protein, and a second region comprising a spacer sequence that hybridizes to a target sequence in the target nucleic acid.