Figure 1.

Muscle formation and gene expression patterns in the Drosophila embryo as modulated by specific cell ablation, antisense expression, and RNA interference by the injection of dsRNA. Ablation of the nautilus-positive muscle founder cells by ricin toxin disrupts muscle formation. (A) Ricin not induced. (B and C) Ricin induced in nautilus-positive cells. Antisense expression of nautilus RNA disrupts muscle formation in three different UAS antisense (AS) nautilus lines (D– F). Injection of nautilus dsRNA blocks muscle formation (G and H) and does not depend on the bHLH domain for the disruption [dsRNA for the C terminus (I), dsRNA for the bHLH domain (J), and dsRNA for the amino terminus of nautilus (K)]. Injection of β-galactosidase dsRNA does not disrupt the muscle pattern but eliminates normal lacZ expression (shown in M) without affecting muscle pattern (similar to A), whereas injection of nautilus dsRNA into a nautilus lacZ line 14.1 disrupts the lacZ muscle pattern (compare M and N) and reduces lacZ expression. Injection of dsRNA for DMEF2 [uninjected (L) and injected (O)], S59 [uninjected (P) and injected (Q)], daughterless [uninjected (R) and injected (S); C, CNS; P, PNS], and white [uninjected (T) (w+) and injected (U)] results in the disruption of gene function for these genes. A–L and O–Q were stained with antimyosin; M and N were stained with 5-bromo-4-chloro-3-indolyl β-d-galactoside; R and S were stained with monoclonal 22C10 and horseradish peroxide for CNS and PNS. AS in the upper left-hand corner marks the nautilus antisense lines, -U indicates the uninjected phenotype for the designated gene, and -I indicates dsRNA injection for the indicated gene.