The fully developed and functional Drosophila midgut comprises two layers, the visceral mesoderm and the endoderm. The visceral muscle of the midgut is formed by the fusion of founder cells with fusion competent cells to create the muscle syncytia. The specification of those cells and therefore the fusion and the forming of the midgut muscle would depend on the Receptor tyrosine kinase (RTK) Alk (Loren et al., 2003). The endoderm underlies the visceral muscle and is formed from cells that result from the anterior and the posterior areas of the embryo. These cells make use of the visceral mesoderm as a substrate because of their migration. Using Alk mutant animals, we now have studied endoderm migration throughout embryonic development. As the initial migration of the endoderm isn’t affected in the lack of the visceral mesoderm, we realize that the later dorsal-ventral endodermal migration does maybe not occur. The development of the visceral muscle and its own reliance on the endoderm is badly comprehended. We now have analysed gürtelchen (gurt) mutant animals, originally identified in a genetic screen for mutations affecting visceral muscle formation. Gurt mutants are so named because of their belt-like phenotype of the visceral muscle (gürtelchen is German for belt)….
Contents: Midgut and muscle development in Drosophila melanogaster
INTRODUCTION
Drosophila as a model system to study midgut development
Genetic tools in Drosophil
How it all starts – Drosophila gastrulation
Endoderm development in Drosophila
Formation of the midgut endoderm
Molecular signals driving the midgut endoderm formation
Formation of the midgut visceral muscles
The Receptor Tyrosine kinase Alk and its role in cell specification in the visceral
Mesoderm
Molecular targets of the RTK ALK in the embryonic midgut
Alk in human disease
Development of the somatic muscles in Drosophila
Architecture of the larval somatic muscle and muscle attachment sites
The sarcomeric structure of muscles
Guanine exchange factors and their role as regulators of small GTPases
Rap GTPases and their effectors
AIMS
RESULTS AND DISCUSSION…
Source: Umea University