Researchers have found the gene switch that is responsible for the formation of flight muscles.
This research has been done by the scientists from Max Planck Institute of Biochemistry in Martinsried near Munich, Germany, and published online in the November 16 issue of the journal Nature.
Fruit fly, Drosophila melanogaster, moves her wings at a frequency of 200 times per second. Researchers have found that the gene spalt is important for the formation of ultrafast super muscles. Without this gene, fly cannot build flight muscles instead they build only normal leg muscles. Flight muscles are unique as their contractions are not only regulated by nerve impulses but also triggered by tension. Flies have two types of flight muscles enabling the oscillations of the wing. One type of muscle moves the wings down and stretches the other type, at the same time, which induces its contraction. Such, the wings are again pulled up and stable oscillations of the wing start.
Studies showed that the transcription factors like Spalt have an important function in the correct transcription of the genetic information into RNA and proteins necessary in the respective cell types. Spalt exists in flight muscles and is responsible for special architecture of myofibrils present in the muscles. These components of muscle fibers alone allow the contraction of the muscle in response to the applied tension during oscillations. Without Spalt, flies are flightless.
On the other hand, scientists successfully create flight muscle like muscles in the fly’s legs by inserting Spalt.
Frank Schnorrer, head of the research group, said,
Human body muscles do not have Spalt and are hardly regulated by tension. But the human cardiac muscle builds Spalt and the tension inside the ventricle influences the heartbeat intensity. Whether Spalt plays a role in heartbeat regulation, is not yet known and remains to be investigated.
Cornelia Schönbauer, Jutta Distler, Nina Jährling, Martin Radolf, Hans-Ulrich Dodt, Manfred Frasch & Frank Schnorrer, (2011). Spalt mediates an evolutionarily conserved switch to fibrillar muscle fate in insects. Frank Schnorrer, doi:10.1038/nature10559