CRISPR-Cas9 genome editing technology was used to introduce a short 49-bp synthetic polyadenylation signal (spA) in exon 1 proximal to the transcription start site of HOXA11os. This results in a complete loss of HOXA11os transcripts 1 and 2 in the distal colon with no effect on the expression of the proximal protein-coding gene HOXA11 under basal or colitis conditions.