UASt regulatory sequences are fused upstream of the E2f1-RA isoform 5'UTR and coding sequence, and the longer (1265bp) E2f1 3'UTR. The coding sequence is tagged at the N-terminal end with sfGFP. The 5'UTR sequence has been mutated so that single nucleotide substitutions (ATG to AAG) remove all 11 start codons of the upstream open reading frame (uORF) present in the 5'UTR.