Article

Myogenesis: A View from Drosophila

University of Cambridge, Cambridge, England, United Kingdom
Cell (Impact Factor: 32.24). 07/1998; 93(6):921-7. DOI: 10.1016/S0092-8674(00)81198-8
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Available from: Mary Baylies, Aug 28, 2015
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    • "In Drosophila larva, a repeated pattern of 30 unique muscle fibers is present in each abdominal hemi-segment (Bate, 1990), which are innervated by 36 motor neurons (Landgraf et al. 2003). Each muscle fiber is distinguishable by size, shape, orientation, number of nuclei, innervation, and tendon attachment sites (Baylies et al. 1998). Throughout development, internal and external cues guide muscles to adopt specific properties that allow them to perform particular functions. "
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    ABSTRACT: Drosophila Nedd4 (dNedd4) is a HECT ubiquitin ligase with two main splice isoforms: dNedd4 short (dNedd4S) and long (dNedd4Lo). DNedd4Lo has a unique N-terminus containing a Pro-rich region. We previously showed that while dNedd4S promotes neuromuscular synaptogenesis, dNedd4Lo inhibits it and impairs larval locomotion. To delineate the cause of the impaired locomotion, we searched for binding partners to the N-terminal unique region of dNedd4Lo in larval lysates using mass-spectrometry and identified Amphiphysin (dAmph). dAmph is a postsynaptic protein containing SH3-BAR domains, which regulates muscle transverse tubule (T-tubule) formation in flies. We validated the interaction by coimmunoprecipitation and showed direct binding between dAmph-SH3 domain and dNedd4Lo-N-terminus. Accordingly, dNedd4Lo was colocalized with dAmph postsynaptically and at muscle T-tubules. Moreover, expression of dNedd4Lo in muscle during embryonic development led to disappearance of dAmph and to impaired T-tubule formation, phenocopying amph null mutants. This effect was not seen in muscles expressing dNedd4S or a catalytically-inactive dNedd4Lo(C->A). We propose that dNedd4Lo destabilizes dAmph in muscles, leading to impaired T-tubule formation and muscle function.
    Preview · Article · Jan 2016 · Molecular Biology of the Cell
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    • "Given the complexity of the Drosophila larval muscle pattern, myoblast fusion is a highly regulated process (reviewed in (Abmayr and Pavlath, 2012)). Characterization of selected muscle lineages has established that muscle identity -orientation, shape, size/number of nuclei, epidermal attachment sites characteristic of each muscle -, reflects the expression and function in each PC and FC of a specific combination of muscle identity transcription factors (iTFs) (Baylies et al., 1998; de Joussineau et al., 2012; Enriquez et al., 2012; Frasch, 1999). The A2-A7 segments present roughly the same pattern of body wall muscles. "
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    ABSTRACT: The body plan of arthropods and vertebrates involves the formation of repetitive segments, which subsequently diversify to give rise to different body parts along the antero-posterior/rostro-caudal body axis. Anatomical variations between body segments are crucial for organ function and organismal fitness. Pioneering work in Drosophila has established that Hox transcription factors play key roles both in endowing initially identical segments with distinct identities and organogenesis. The focus of this review is on Alary Muscles (AMs) and the newly discovered Thoracic Alary-Related Muscles (TARMs). AMs and TARMs are thin muscles which together connect the circulatory system and different midgut regions to the exoskeleton, while intertwining with the respiratory tubular network. They were hypothesized to represent a new type of muscles with spring-like properties, maintaining internal organs in proper anatomical positions during larval locomotion. Both the morphology of TARMs relative to AMs, and morphogenesis of connected tissues is under Hox control, emphasizing the key role of Hox proteins in coordinating the anatomical development of the larva. Copyright © 2015. Published by Elsevier Ireland Ltd.
    Full-text · Article · Jul 2015 · Mechanisms of development
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    • "FCs are born from the asymmetric division of progenitor cells (PCs) specified at precise positions and times within the somatic mesoderm. Detailed characterization of a few somatic muscle lineages has established that muscle identity (specific shape, size, orientation) reflects the expression of specific muscle identity transcription factors (iTFs) in each FC that act in a combinatorial manner (Baylies et al., 1998; Frasch, 1999; de Joussineau et al., 2012; Enriquez et al., 2012). "
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    ABSTRACT: The T-box transcription factor Tbx1 and the LIM-homeodomain transcription factor Islet1 are key components in regulatory circuits that generate myogenic and cardiogenic lineage diversity in chordates. We show here that Org-1 and Tup, the Drosophila orthologs of Tbx1 and Islet1, are co-expressed and required for formation of the heart-associated alary muscles (AMs) in the abdomen. The same holds true for lineage-related muscles in the thorax that have not been described previously, which we name thoracic alary-related muscles (TARMs). Lineage analyses identified the progenitor cell for each AM and TARM. Three-dimensional high-resolution analyses indicate that AMs and TARMs connect the exoskeleton to the aorta/heart and to different regions of the midgut, respectively, and surround-specific tracheal branches, pointing to an architectural role in the internal anatomy of the larva. Org-1 controls tup expression in the AM/TARM lineage by direct binding to two regulatory sites within an AM/TARM-specific cis-regulatory module, tupAME. The contributions of Org-1 and Tup to the specification of Drosophila AMs and TARMs provide new insights into the transcriptional control of Drosophila larval muscle diversification and highlight new parallels with gene regulatory networks involved in the specification of cardiopharyngeal mesodermal derivatives in chordates.
    Full-text · Article · Oct 2014 · Development
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