37th Annual Drosophila Research Conference San Diego, California 27 April–1 May 1996
✍ Scribed by Richard M. Cripps
- Publisher
- Springer Netherlands
- Year
- 1996
- Tongue
- English
- Weight
- 209 KB
- Volume
- 17
- Category
- Article
- ISSN
- 0142-4319
No coin nor oath required. For personal study only.
✦ Synopsis
kicked off the slide session by describing how the early specification of a subset of muscle cells is regulated by a complex network of intercellular signalling molecules. Some somatic muscle founder cells and a subset of pericardial cells express the even-skipped (eve) gene. In these cells, eve expression requires both the TGF~ homologue decapentaplegic (dpp) and the wnt family member wingless (wg). Only where the expression domains of these proteins intersect is an "equivalence group" generated, within which ras is initially activated in all cells. Subsequently lateral inhibition via Delta, a cell-surface molecule, results in the identification of single muscle precursor cells within each equivalence group.
Intercellular signalling was one of the major themes this year as Alan Michelson and Talila Volk (Weizmann Institute of Science, Israel) both described their analyses of the gene heartless (htl). In heartless mutants, mesodermal cells do not migrate dorsally after gastrulation. This results in fewer cells receiving the dorsally-derived dpp signal which is essential for the specification of the dorsal mesoderm into heart and gut musculature. Both Alan and Talila demonstrated that the htl product is an FGF receptor which is expressed in the entire mesoderm from gastrulation onwards. Talila also showed that the htl protein persists in mesodermal derivatives at later stages, and postulated that it may be required for later cell migration and arrangement events.
Eugene Buff (Harvard University School of Medicine) discussed the role of another receptor, the EGF receptor, in somatic muscle cell determination. A reduction in EGFR activity results in the absence of several muscle founder cells.