A sub-region of the nerfin-1 3'UTR (266bp, contains the mir-305/mir-13b-1/mir-13b-2 miRNA-binding sites) has been inserted into a Not-I site within the SV40 3'UTR of Avic\GFPEGFP.nerfin-1.SV40.Tag:NLS(tra), 14bp 3' of the EGFP ORF translation stop codon.