Evelopmental stage), mechanosensory bristle pigmentation initiated earlier than in neighboring wildtype

Evelopmental stage), mechanosensory bristle pigmentation initiated earlier than in neighboring wildtype bristles (Fig. 1J ). In contrast, pigmentation was delayed compared to wildtype bristles in marked rheb, tsc1 double mutant clones (Fig. 1N, O), suggesting that rheb is required for the precocious pigmentation in tsc1 clones. Taken together, we conclude that Rheb activity is a limiting factor in the timing and degree of adult pigmentation on the thorax and abdomen.Rheb induced pigmentation, we knocked down s6k1 by RNAi in the thorax with pannier-Gal4. s6k1RNAi stunts mechanosensory bristle growth in both wildtype and Rheb overexpressing flies, but does not suppress melanization in wildtype flies. However, s6k1RNAi potently suppresses Acetovanillone cuticular pigmentation in Rheb overexpressing flies (Fig. 2F). To assess whether S6K1 activity was sufficient to drive increased pigmentation on the thorax, we crossed pannier-Gal4 to UAS transgenes encoding S6 kinase mutants that mimic an activating phosphorylation (S6K1TE) [18]. This activated form of S6K1 markedly enhanced Rhebdependent pigmentation (Fig. S1I, J). Furthermore, 4 IBP biological activity overexpression of the S6K1TE or S6K1STDETE mutant (both which possesses the T398 to E amino acid substitution in the linker domain) results in a mild increased pigmentation phenotype on the thorax when pupae are grown at 29uC (Fig. 2G). We hypothesized that since TORC1 activation promotes both S6K1 activity and releases repression on eIF4E, that activation of S6K1 alone was perhaps not sufficient to fully recapitulate the pigmentation phenotype caused by Rheb. We therefore asked whether combined expression of S6K1TE and eIF4E could yield a robust increase in pigmentation on the thorax. Indeed, we find that while overexpression of eIF4E alone has no effect, eIF4E overexpression enhanced the increased pigmentation phenotype resulting from S6K1TE overexpression at 29uC (Fig. 2H). Due to severe distortion of thorax morphology, we were unable to assess whether overexpression of 4E-BP, which acts an inhibitor of eIF4E, could suppress Rheb-induced pigmentation. Taken together, our findings lead us to conclude that Rheb-induced pigmentation on the thorax requires TORC1 complex components Raptor and TOR, and the combined hyperactivity of S6K1 and eIF4E are sufficient to drive darkening of the cuticle.TORC1 Regulation of S6K and eIF4E is Required for Rhebinduced PigmentationThe TORC1 complex, which contains TOR kinase, is the primary target of Rheb in promoting cell growth (Fig. 1A). We found that Rheb could not drive increased pigmentation in tor mutant cells (Fig. 2A ). However, Tor kinase is a component of two complexes, TORC1 and TORC2. TORC1 is a primary target of Rheb activation and Raptor is the TORC1-specific subunit of the complex that mediates the interaction between TORC1 and its effectors [16]. In order to specifically target TORC1 we crossed pannier-Gal4, and pannier-Gal4, UAS-Rheb flies to two independent UAS-raptorRNAi lines from the TRiP Drosophila RNAi collection (TRiP.JF01087 and TRiP.JF01088 [17]). Consistent with TORC1’s role in cell growth, knockdown of Raptor by expression of either UAS-raptorRNAi line with pannier-Gal4 reduced mechanosensory bristle size along a central dorsal stripe on the thorax. raptor knockdown also completely suppressed Rheb-induced pigmentation on the thorax and caused diminished pigmentation along the dorsal region of abdominal segments in both the control and Rheb overexpressing flies (Fig. 2.Evelopmental stage), mechanosensory bristle pigmentation initiated earlier than in neighboring wildtype bristles (Fig. 1J ). In contrast, pigmentation was delayed compared to wildtype bristles in marked rheb, tsc1 double mutant clones (Fig. 1N, O), suggesting that rheb is required for the precocious pigmentation in tsc1 clones. Taken together, we conclude that Rheb activity is a limiting factor in the timing and degree of adult pigmentation on the thorax and abdomen.Rheb induced pigmentation, we knocked down s6k1 by RNAi in the thorax with pannier-Gal4. s6k1RNAi stunts mechanosensory bristle growth in both wildtype and Rheb overexpressing flies, but does not suppress melanization in wildtype flies. However, s6k1RNAi potently suppresses cuticular pigmentation in Rheb overexpressing flies (Fig. 2F). To assess whether S6K1 activity was sufficient to drive increased pigmentation on the thorax, we crossed pannier-Gal4 to UAS transgenes encoding S6 kinase mutants that mimic an activating phosphorylation (S6K1TE) [18]. This activated form of S6K1 markedly enhanced Rhebdependent pigmentation (Fig. S1I, J). Furthermore, overexpression of the S6K1TE or S6K1STDETE mutant (both which possesses the T398 to E amino acid substitution in the linker domain) results in a mild increased pigmentation phenotype on the thorax when pupae are grown at 29uC (Fig. 2G). We hypothesized that since TORC1 activation promotes both S6K1 activity and releases repression on eIF4E, that activation of S6K1 alone was perhaps not sufficient to fully recapitulate the pigmentation phenotype caused by Rheb. We therefore asked whether combined expression of S6K1TE and eIF4E could yield a robust increase in pigmentation on the thorax. Indeed, we find that while overexpression of eIF4E alone has no effect, eIF4E overexpression enhanced the increased pigmentation phenotype resulting from S6K1TE overexpression at 29uC (Fig. 2H). Due to severe distortion of thorax morphology, we were unable to assess whether overexpression of 4E-BP, which acts an inhibitor of eIF4E, could suppress Rheb-induced pigmentation. Taken together, our findings lead us to conclude that Rheb-induced pigmentation on the thorax requires TORC1 complex components Raptor and TOR, and the combined hyperactivity of S6K1 and eIF4E are sufficient to drive darkening of the cuticle.TORC1 Regulation of S6K and eIF4E is Required for Rhebinduced PigmentationThe TORC1 complex, which contains TOR kinase, is the primary target of Rheb in promoting cell growth (Fig. 1A). We found that Rheb could not drive increased pigmentation in tor mutant cells (Fig. 2A ). However, Tor kinase is a component of two complexes, TORC1 and TORC2. TORC1 is a primary target of Rheb activation and Raptor is the TORC1-specific subunit of the complex that mediates the interaction between TORC1 and its effectors [16]. In order to specifically target TORC1 we crossed pannier-Gal4, and pannier-Gal4, UAS-Rheb flies to two independent UAS-raptorRNAi lines from the TRiP Drosophila RNAi collection (TRiP.JF01087 and TRiP.JF01088 [17]). Consistent with TORC1’s role in cell growth, knockdown of Raptor by expression of either UAS-raptorRNAi line with pannier-Gal4 reduced mechanosensory bristle size along a central dorsal stripe on the thorax. raptor knockdown also completely suppressed Rheb-induced pigmentation on the thorax and caused diminished pigmentation along the dorsal region of abdominal segments in both the control and Rheb overexpressing flies (Fig. 2.

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