FIGURE 8.

BNGR-A21 expression in tissues and effects of exogenous corazonin and dsRNA-mediated expression knock-down on silk spinning and growth. A, BNGR-A21 expression in tissues of fifth larval instar. BR, brain; EP, epidermis; FB, fat body; MG, midgut; MT, Malpighian tubule; OV, ovary; TE, testis; SiG, Poster silk gland. Transcript levels of the BNGR-A21 mRNA were normalized to that of β-actin within each sample. B, effect of dsRNA injection on BNGR-A21 expression in different tissues. BNGR-A21 dsRNA (10 μg) was injected on the second day of fifth instar larvae. BNGR-A21 gene expression was determined by RT-PCR 36 h after injection. Each cDNA was analyzed in triplicate and bars represent the S.D. C, effects of [Arg⁷]corazonin injection on silkworm body weight. D, effects of dsRNA treatment on silkworm body weight and cocoon layer. Effects of [Arg⁷]corazonin injection on cocoon with pupa (E) and cocoon layer (G). Effects of dsRNA treatment on cocoon with pupa (F) and (H) cocoon layer. All panels are representative of at least three independent experiments (ns, not significant; *, p < 0.05; **, p < 0.01; ***, p < 0.001).