Segmental differences in the protein content of Drosophila imaginal discs (original) (raw)
Related papers
Biophysical Journal, 2004
Wild-type and mutant thin filaments were isolated directly from ''myosinless'' Drosophila indirect flight muscles to study the structural basis of muscle regulation genetically. Negatively stained filaments showed tropomyosin with periodically arranged troponin complexes in electron micrographs. Three-dimensional helical reconstruction of wild-type filaments indicated that the positions of tropomyosin on actin in the presence and absence of Ca 21 were indistinguishable from those in vertebrate striated muscle and consistent with a steric mechanism of regulation by troponin-tropomyosin in Drosophila muscles. Thus, the Drosophila model can be used to study steric regulation. Thin filaments from the Drosophila mutant heldup 2 , which possesses a single amino acid conversion in troponin I, were similarly analyzed to assess the Drosophila model genetically. The positions of tropomyosin in the mutant filaments, in both the Ca 21 -free and the Ca 21 -induced states, were the same, and identical to that of wild-type filaments in the presence of Ca 21 . Thus, cross-bridge cycling would be expected to proceed uninhibited in these fibers, even in relaxing conditions, and this would account for the dramatic hypercontraction characteristic of these mutant muscles. The interaction of mutant troponin I with Drosophila troponin C is discussed, along with functional differences between troponin C from Drosophila and vertebrates.
Electron microscopic and electrophoretic studies of a Drosophila muscle mutant wings-up B
The Japanese journal of genetics, 1981
Electron microscopy revealed that, although both thick and thin filaments are present, Z-band and myofibrillar organization are totally lost in indirect flight muscle (IFM) of a Drosophila muscle mutant wings-up B (wup B). The Z-band deficiency correlates well with the gene dosage; in wup B/wup B+ heterozygotes, normal internal structure of the Z-band is restricted only within the central core of the myofibrils. Two-dimensional gel electrophoresis (0'Farrell 1975) revealed that nine myofibrillar proteins are either absent or reduced in the indirect flight muscle of the mutant. Some of the anomalies are not restored in heterozygotes. These observations suggest a possibility that the product of wup B+ gene is one of the Z-band components, without which the regular arrangement of thick and thin filaments cannot be maintained. Possible mechanisms for the fact that a single mutation causes multiple changes on the gel are discussed. We concluded that absence of one component causes disappearance or reduction of others which are functionally and/or structurally related.
The mechanism of evagination of imaginal discs of Drosophila melanogaster
American …, 1977
SYNOPSIS The evagination of imaginal leg discs to produce legs is a useful model for studying morphogenesis. Evagination of imaginal leg discs occurs in vitro in defined culture media in the presence of the molting hormone /3-ecdysone. Evagination involves limited, organized movement of imaginal disc cells. The movement appears to be a result of contractile activity, coordinated with the presence of appropriate structural and surface properties of disc cells. However, ecdysone does not produce its effects directly, but acts through the genome to cause evagination. Evagination is a result then of increased synthesis of different proteins, one of which is myosin. If the results on discs are generalizable they indicate that similar morphogenetic processes are the direct result of the readout of the specific genetic programs. This paper is number four in a series on the mechanism of evagination of imaginal discs. We acknowledge the expert technical assistance of Mrs. Odessa Eugene and Mrs. Susie Kuniyuki.
Development, 2012
In the past, segments were defined by landmarks such as muscle attachments, notably by Snodgrass, the king of insect anatomists. Here, we show how an objective definition of a segment, based on developmental compartments, can help explain the dorsal abdomen of adult Drosophila. The anterior (A) compartment of each segment is subdivided into two domains of cells, each responding differently to Hedgehog. The anterior of these domains is non-neurogenic and clones lacking Notch develop normally; this domain can express stripe and form muscle attachments. The posterior domain is neurogenic and clones lacking Notch do not form cuticle; this domain is unable to express stripe or form muscle attachments. The posterior (P) compartment does not form muscle attachments. Our in vivo films indicate that early in the pupa the anterior domain of the A compartment expresses stripe in a narrowing zone that attracts the extending myotubes and resolves into the attachment sites for the dorsal abdomina...
Evolution & Development, 2007
We characterize a newly discovered morphological difference between species of the Drosophila melanogaster subgroup. The muscle of Lawrence (MOL) contains about four to five fibers in D. melanogaster and Drosophila simulans and six to seven fibers in Drosophila mauritiana and Drosophila sechellia. The same number of nuclei per fiber is present in these species but their total number of MOL nuclei differs. This suggests that the number of muscle precursor cells has changed during evolution. Our comparison of MOL development indicates that the species difference appears during metamorphosis. We mapped the quantitative trait loci responsible for the change in muscle fiber number between D. sechellia and D. simulans to two genomic regions on chromosome 2. Our data eliminate the possibility of evolving mutations in the fruitless gene and suggest that a change in the twist might be partly responsible for this evolutionary change. Evolution of muscle ¢ber number 369 Orgogozo et al.
Development, 1991
During metamorphosis, the adult muscles of the Drosophila abdomen develop from pools of myoblasts that are present in the larva. The adult myoblasts express twist in the third larval instar and the early pupa and are closely associated with nerves. Growing adult nerves and the twist-expressing cells migrate out across the developing abdominal epidermis, and as twist expression declines, the myoblasts begin to synthesize beta 3 tubulin. There follows a process involving cell fusion and segregation into cell groups to form multinucleate muscle precursors. These bipolar precursors migrate at both ends to find their correct attachment points. beta 3 tubulin expression continues at least until 51 h APF by which time the adult muscle pattern has been established.
The Journal of Experimental Biology, 1998
Striated muscle cells contain a highly ordered, threedimensional cytoskeletal network specialized for the generation and transmission of contractile forces. Myosincontaining thick filaments and actin-containing thin filaments are organized as interdigitating arrays that allow the cyclical interaction of myosin with actin, thus producing the force for work. The spatial arrangement of contractile myofilaments is dictated in part by two cross-linking structures, the M line and the Z band, whose variation in structure in part reflects tissue and/or fiber-specific differences in muscle properties (Squire, 1986; Schachat et al. 1985; Vigoreaux, 1994). The assembly and stability of the sarcomeric lattice results from diverse but poorly defined molecular interactions among structural proteins. Temporal scaffolding structures (e.g. sleeves of microtubules, Reedy and Beall, 1993) have been shown to participate in muscle fiber assembly but play no role in defining the structural stability of the actively contracting fiber. Contracting muscle cells undergo continuous changes in cell shape. A highly dynamic cytoskeleton well-suited to respond and adjust to internally derived tension and externally applied stress underlies these changes. Although the mechanism for generating contractile force has received a lot of attention, the ability of the muscle cell to contract and return to its original shape unscathed is often taken for granted. As a result, we know very little about the mechanism for preserving cellular integrity and of the molecular interactions that define the dynamic nature of the cytoskeleton. Genetic approaches have proved exceedingly useful for the analysis of muscle fiber assembly and muscle function (for reviews, see Epstein and Fischman, 1991; Bernstein et al. 1993). The indirect flight muscles (IFMs) of Drosophila melanogaster are well suited for genetic studies because the effects of a mutation can be studied in vivo as well as in situ using a combination of well-established functional, ultrastructural, mechanical and biochemical assays (Tohtong et al. 1995; Kreuz et al. 1996; Dickinson et al. 1997). Several mutations in contractile protein genes have been identified that appear to have little or no effect on myofibril assembly but which lead to rapid degeneration of the adult muscle. For example, Kronert et al. (1995) reported the characterization of three missense alleles of the myosin heavy chain gene that cause single amino acid changes in the light meromyosin region of the rod. None of the mutations appears to interfere with the normal assembly of myofibrils, but all three lead to sarcomeric degeneration as the adult ages (Kronert et al. 1995). An age-dependent degeneration of flight muscle has also been 2033
Myogenesis in Drosophila melanogaster: Dissection of Distinct Muscle Types for Molecular Analysis
Methods in Molecular Biology, 2018
Drosophila is a useful model organism for studying the molecular signatures that define specific muscle types during myogenesis. It possesses significant genetic conservation with humans for muscle disease causing genes and a lack of redundancy that simplifies functional analysis. Traditional molecular methods can be utilized to understand muscle developmental processes such as Western blots, in situ hybridizations, RT-PCR and RNAseq, to name a few. However, one challenge for these molecular methods is the ability to dissect different muscle types. In this protocol we describe some useful techniques for extracting muscles from the pupal and adult stages of development using flight and jump muscles as an example.