Oligonucleotide bcd3T including three copies of the bcd binding site inserted towards the 5' end of the lacZ gene.
The EcollacZbcd.3TRtranscript is expressed in the anterior region of the embryo. Duringcellularization, expression is detected in an "anterior cap", then begins toreceed from the anterior, and finally during gastrulation, forms a stripe ofexpression between 15% and 20% egg length.