title: Sallimus and the dynamics of sarcomere assembly in Drosophila flight muscles.
abstract: The Drosophila indirect flight muscles (IFM) can be used as a model for the study of sarcomere assembly. Here we use a transgenic line with a green fluorescent protein (GFP) exon inserted into the Z-disc-proximal portion of sallimus (Sls), also known as Drosophila titin, to observe sarcomere assembly during IFM development. Firstly, we confirm that Sls-GFP can be used in the heterozygote state without an obvious phenotype in IFM and other muscles. We then use Sls-GFP in the IFM to show that sarcomeres grow individually and uniformly throughout the fibre, growing linearly in length and in diameter. Finally, we show that limiting the amounts of Sls in the IFM using RNAi leads to sarcomeres with smaller Z-discs in their core, whilst the thick/thin filament lattice can form peripherally without a Z-disc. Thick filament preparations from those muscles show that although the Z-disc-containing core has thick filaments of a regular length, filaments from the peripheral lattice are longer and asymmetrical around the bare zone. Therefore, the Z-disc and Sls are required for thick filament length specification but not for the assembly of the thin/thick filament lattice.
authors: Department of Biology, University of York, York YO10 5DD, UK. Electronic address: orfanos@uni-bonn.de.
authors: Zacharias
authors: Z
authors: Orfanos
authors: European Molecular Biology Laboratory European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire CB10 1SD, UK.
authors: Kevin
authors: K
authors: Leonard
authors: Department of Biology, University of York, York YO10 5DD, UK.
authors: Chris
authors: C
authors: Elliott
authors: Department of Biology, University of York, York YO10 5DD, UK; Present address: Department of Biology, McGill University, Montreal, Quebec, Canada H3A 1B1.
authors: Anja
authors: A
authors: Katzemich
authors: Department of Biology, University of York, York YO10 5DD, UK.
authors: Belinda
authors: B
authors: Bullard
authors: Department of Biology, University of York, York YO10 5DD, UK.
authors: John
authors: J
authors: Sparrow
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D064211:Connectin / Q000378:metabolism*; D004330:Drosophila / Q000201:enzymology* / Q000254:growth & development / Q000502:physiology*; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D009132:Muscles / Q000201:enzymology / Q000502:physiology; D012518:Sarcomeres / Q000378:metabolism*; D013194:Staining and Labeling / Q000379:methods
chemical_list: D064211:Connectin; C577347:sls protein, Drosophila; D049452:Green Fluorescent Proteins
keywords: D-titin; Z-disc; thick filaments