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Dual function of the region-specific homeotic gene spalt during Drosophila tracheal system development

1996; The Company of Biologists; Volume: 122; Issue: 7 Linguagem: Inglês

10.1242/dev.122.7.2215

1477-9129

Ronald P. Kühnlein, Reinhard Schuh,

Wnt/β-catenin signaling in development and cancer

ABSTRACT We report that the region-specific homeotic gene spalt affects the Drosophila tracheal system at two different stages of embryonic development. Both lack-of-function and gain-of-function experiments show that blastodermal spalt activity restricts tracheal development to 10 bilaterally positioned pairs of tracheal placodes in the trunk region by repressing placode formation in parasegments 2, 3 and 14. The results suggest that the activity of the zinkfinger type transcription factor encoded by spalt suppresses the molecular pathway that establishes tracheal development. spalt function is also necessary for the directed migration of the dorsal trunk cells, a distinct subset of tracheal cells. This process is a prerequisite for the formation of the dorsal trunk generated by fusion of adjacent tracheal metameres into a common tubular structure. The directed cell migration, in which spalt gene function participates, seems to be independent of branch fusion and general tracheal cell migration processes.