A 150bp ocn promoter fragment (including 80bp of 5' flanking sequence and 70bp of 5'UTR) which corresponds to -165 to -16 relative to the A in the ATG start codon is fused upstream of the lacZ open reading frame. The ocn 3'UTR sequence (-16 to +93 relative to the T in the TGA stop codon) is present downstream of the lacZ coding region.