Figure 2.

Modulator blocking activity by sns sequences in microinjected sea urchin embryos. (Top) CAT RNA transcripts were detected by RNase protection assay. ³²P-labeled antisense RNA, transcribed in vitro from the H2A-CAT DNA containing a pUC18 insert (28) and schematically drawn (Middle), was hybridized with total RNA extracted from 50 sea urchin embryos at the indicated developmental stage, microinjected with the constructs A-F depicted (Bottom) or with 100 μg of yeast tRNA. One half of the RNase-resistant products were run on denaturing polyacrylamide gel along with labeled HpaII-digested end labeled pUC18 fragments (lane M). Only fragments ranging from 353 bp to 110 bp are shown. Gels were dried and exposed overnight at −80°C with an intensifying screen. The expected 217-nucleotide resistant fragment is indicated by an arrow.