本帖最后由 细胞海洋 于 2011-11-17 23:28 编辑 . ?( @. t$ }( D# t8 @ c9 n$ L+ H% F# c4 O
The indirect flight muscles of flying insects have evolved to power insects' wings through as many as 1,000 oscillations per second and to produce extreme mechanical forces. These exquisitely specialized muscles contain fibrillar, stretch-activated myofibres that are very different from the tubular muscles found elsewhere in the insect’s body. A genome-wide RNA interference screen for muscle morphogenesis in Drosophila has identified the transcription factor Spalt major (Salm) as a master regulator of fibrillar flight-muscle fate. Salm switches the structure of muscles from tubular to fibrillar during development by regulating gene transcription and splicing. The spalt gene is conserved in insects that are separated by 280 million years of evolution, and the fact that mutations in the human spalt-like gene SALL1 cause heart abnormalities in Townes–Brocks syndrome suggests that spalt function might also determine fibrillar stretch-activated muscle in vertebrates. On the cover, a blow fly (Calliphora sp.) shows how it’s done. Image: Frank Schnorrer/Monika Krause/Väinö Haikala (MPI) 1 f. J, o' f9 @( {[attach]35703[/attach]( ] G: x; f% B- S9 f) y6 J
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