Absence of the Drosophila jump muscle actin Act79B is compensated by up‐regulation of Act88F

Abstract

Background: Actins are structural components of the cytoskeleton and muscle, and numerous actin isoforms are found in most organisms. However, many actin isoforms are expressed in distinct patterns allowing each actin to have a specialized function. Numerous studies have demonstrated that actin isoforms both can and cannot compensate for each other under specific circumstances. This allows for an ambiguity of whether isoforms are functionally distinct. Results: In this study, we analyzed mutants of Drosophila Act79B, the predominant actin expressed in the adult jump muscle. Functional and structural analysis of the Act79B mutants found the flies to have normal jumping ability and sarcomere structure. Analysis of actin gene expression determined that expression of Act88F, an actin gene normally expressed in the flight muscles, was significantly up-regulated in the jump muscles of mutants. This indicated that loss of Act79B caused expansion of Act88F expression. When we created double mutants of Act79B and Act88F, this abolished the jump ability of the flies and resulted in severe defects in myofibril formation. Conclusions: These results indicate that Act88F can functionally substitute for Act79B in the jump muscle, and that the functional compensation in actin expression in the jump muscles only occurs through Act88F. Developmental Dynamics 247:642–649, 2018.

Differences in Postmating Transcriptional Responses between Conspecific and Heterospecific Matings inDrosophila

“…4 ). In addition, one of the 11 genes is orthologous to the D. melanogaster actin gene, Act79B , which localizes to the actin cytoskeleton and is often expressed in muscle tissue ( Dohn and Cripps 2018 ). Conversely, only one gene—an fRT-biased, textilinin-like protease inhibitor—shows higher abundance in the heterospecific sample compared to the conspecific sample.…”

Rbfox1 is required for myofibril development and maintaining fiber-type specific isoform expression inDrosophilamuscles

“…sgRNA sequences and homology arm primers are listed in Supplemental Table 2. Gal4 drivers used were: Mef2-Gal4 (Ranganayakulu et al, 1996) which drives in all muscle (maintained at 27 °C or 29 °C); UAS-Dcr2, Mef2-Gal4 which enhances RNAi efficiency (maintained at 22°C); Act5c-Gal4 which drives in all cells (maintained at 27°C and 25°C); Mhc-Gal4 (Davis et al, 1996); UH3-Gal4 (Singh et al, 2014) is a driver with IFM specific expression after 36-40h APF (maintained at 27°C); Act88F-Gal4 (Bryantsev et al, 2012a) is a driver with IFM specific expression after 24h APF (maintained at 25°C) and Act79B-Gal4 (Dohn and Cripps, 2018) is a driver with TDT specific expression (maintained at 27°C). Temperature sensitive Tubulin-Gal80 ts , as noted in figure panels and legends, was used to restrict some knockdown experiments to adult muscle development by a temperature shift of late third instar larvae from 18 ºC to ºC.…”

Regulation of fiber-specific actin expression by the Drosophila SRF ortholog Blistered

“…3A, respectively), and Act88F is not actively expressed in the mature jump muscles (Fig. 3C), although Act88F is transiently expressed in the small cells of the TDT during pupal development (Dohn and Cripps, 2018). To investigate this experimentally, we ectopically expressed the Exd/Hth complex in developing jump muscles, to study whether it is sufficient to activate Act88F .…”