The roles of vestigial and scalloped in the embryonic muscle development of Drosophila melanogaster

• Author / Creator

  Deng, Hua

• Vertebrate development requires the activity of multiple members of the myocyte enhancer factor 2 (mef2) gene family for muscle cell specification and subsequent differentiation. Additionally, it is thought that several muscle-specific functions of MEF2 family proteins require binding additional co-factors including members of the Transcription Enhancing Factor-1 (TEF-1) and Vestigial-like protein families. In Drosophila there is a single mef2 (Dmef2) gene as well single homologues of TEF-1 and vestigial-like; sd and vg, respectively. To help clarify the role(s) of these factors, we examined the requirements for Vg and Sd during Drosophila muscle specification. Analysis of loss of Vg or Sd function mutations confirms that both are required for muscle differentiation, as loss of sd or vg leads to a reproducible loss of a subset of cardiac or somatic muscle cells in developing embryos. However, the requirement for Sd or Vg is cell specific, as over-expression of each of these proteins in other muscle cells also has a deleterious effect on muscle differentiation. Finally, I determined that Sd, Vg and Dmef2 can interact directly. Thus, the muscle specific phenotypes associated with loss or ectopic Vg or Sd expression may be a consequence of alternative binding of Vg and Sd to Dmef2 to form alternative protein complexes that modify Dmef2 activity.
  The somatic muscles of Drosophila develop in a complex pattern that is repeated in each embryonic hemi-segment. Initial communication between somatic muscles and the epidermal tendon cells is critical for formation of this muscle pattern. However, later establishment of attachments between longitudinal muscles at the segmental borders is largely independent of the muscle-epidermal attachment signals, and relatively little is known about how this event is regulated. Here I show that expression of the transcription factor Vg is required in ventral longitudinal muscles (VL1-4) to make them competent to form stable inter-muscular attachments. Further, the cell-specific differentiation events induced by Vg in two muscles fated to form attachments appear to be coordinated by Drosophila Epidermal Growth Factor (DER) signalling.

• Subjects / Keywords

  • Muscles
  • Scalloped
  • Drosophila
  • Vestigial

• Graduation date

  Fall 2010

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3X61P

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.