Construct: 7.9kb KpnI-SalI genomic ftz fragment including 6.1kb upstream sequence and one third of ftz 5' transcribed sequences is fused in frame to a 1.3kb SalI-BamHI RpLP2 genomic fragment which encodes the 3' two thirds of the transcribed sequences.
Poly(A)-containing RNAs prepared from synchronous embryos are analysed on RNA blots to measure mRNA stability.