The sequences surrounding the SOX cut site in human mRNAs contain a SOX targeting sequence.

A) Select SOX cut sites chosen for validation, including chromosomal position, parent gene and reproducibility by 5’ RACE and insertion experiment (“elicits cut?”). n.d. = not detected with RACE primers used. B) Diagram of the GFP construct indicating the position of inserted sequences and of Northern blot probes. C-E) 200 nt sequences surrounding SOX cleavage sites in the indicated endogenous genes were cloned into the GFP reporter at nt 715 (with the exception of panel E; in this case the insertion was at nt 459). The GFP- based reporters were then co-expressed with SOX (“+” or “+SOX”) or an empty vector control (“-”) in shXrn1-treated cells and the GFP mRNA from these cells was detected using Northern blotting. The arrowheads point to the additional cleavage fragments resulting from the insertions. Images are representative of results from at least three experimental replicates.