Larvae expressing tn^GD8908 under the control of Scer\GAL4^Mef2.PR or Scer\GAL4^tey-5053A show shorter ventral longitudinal muscles, with sarcomere disorganization, and smaller brains.

Expression of tn^GD8908 under the control of Scer\GAL4^how-24B results in deficit in larval locomotion: the crawling speed, distance from start to finish as well as the total length travelled over time are all significantly reduced in the knock-down third instar larvae compared to controls.

RNAi induction through expression of tn^GD8908 under the control of Scer\GAL4^Mef2.PR and Scer\GAL80^ts.αTub84B after 7 days (corresponding to ~L2) or 10 days (corresponding to ~L3) of development at 28[o]C results in thin myofibrils with nondescript sarcomeres. At the ultrastructural level, short, irregular Z-discs and occasionally M-lines are detected at 1 day post-eclosion; these structures are less evident 10 days later. Consistent with these defects, >90% of these flies are flightless. Induction at day 13 (~late L3/prepupae) initially yields misshapen sarcomeres with longer, more prominent Z-discs however fragmentation, especially at M-lines, is frequently observed at 11 days post-eclosion. Approximately 60-70% of these flies are flightless. Induction at day 16, by which time the adult musculature is normally established, results in much less dramatic effects. Relatively normal sarcomeres with better defined Z-discs and M-lines are present, although occasional, limited dissolution of the M-lines is observed at the later time point. These flies do not exhibit significant flight defects.

Expression of tn^GD8908 using Scer\GAL4^how-24B results in pupae that are thin and long. Compared to wild type, mutant L3 larval skeletal musculature is thinner and looser. At higher magnification, mutant muscles show myofiber instability and unbundling.

A large proportion of tn^GD8908, Scer\GAL4^how-24B animals die during embryogenesis; either no or very low numbers are lost during larval stages; animals that survive the larval stages die as pupae.

Adults expressing tn^GD8908 under the control of Scer\GAL4^elav.PLu (in the presence of Dcr-2^Scer\UAS.cDa to increase the efficiency of RNAi) do not show a significant defect in avoidance of noxious temperature (46[o]C) compared to control flies.

Expression under the control of Scer\GAL4^Mef2.PR results in early pupal lethality.