For the Alt-R™ CRISPR-Cas12a crRNA, the input sequence can vary between 20 and 24 nucleotides. However, based on internal studies, we recommend using a 21-nucleotide sequence as input into the CRISPR-Cas12a crRNA ordering tool.
The ordering tool will automatically convert the DNA sequence to RNA during the ordering process. The 20- or 21-base constant region (loop domain) for the selected Cas12a nuclease (A.s. or L.b. Cas12a) and modifications that confer intracellular nuclease resistance will automatically be added. The final Alt-R CRISPR-Cas12a crRNA will be 40–45 bases.