FIG. 8.

Deletion of the NRE does not affect bicoid mRNA stability. The hollow arrow in the diagram at the top indicates the position of the NRE sequence that was deleted from the bicoid gene. Polyadenylated RNAs were prepared from control (0- to 1-h-old untransformed embryos) and 0- to 1-, 1- to 2-, 2- to 3-, and 3- to 4-h-old embryos from ΔNRE transgenic flies. The RNAs were hybridized with an oligonucleotide (Table 1) complementary to a sequence missing in the ΔNRE construct and digested with RNase H. The RNAs were analyzed on a Northern blot hybridized with bicoid (bcd) and rpA1 mRNA probes. The bicoid mRNA is cleaved into two fragments of 1.6 and 1.0 kb, while the ΔNRE mRNA is unaffected by the treatment. rpA1 mRNA served as a loading control. The control lane shows that wild-type bicoid mRNA is cleaved to completion by the RNase H treatment. mRNA sizes: ΔNRE mRNA, 2.6 kb, and rpA1 mRNA, 0.6 kb.