Salivary duct determination in Drosophila: roles of the EGF receptor signaling pathway and the transcription factors Fork head and Trachealess

Citations Over TimeTop 10% of 1996 papers

Abstract

Organogenesis in Drosophila embryos begins at 4-5 hours of development as the expression of organ-specific genes is initiated. The salivary primordium, which occupies the ventral epidermis of parasegment 2, is among the earliest to be defined. It is soon divided into two distinct regions: the more dorsal pregland cells and the more ventral preduct cells. We show that it is the opposing activities of the Drosophila EGF receptor (DER) signaling pathway and the Fork head transcription factor that distinguish these cell types and set up the boundary between them. DER signaling acts ventrally to block fork head expression in the preduct cells, thereby restricting gland identity to the more dorsal cells. Fork head in turn blocks expression of duct-specific genes in the pregland cells, thereby restricting duct identity to the more ventral cells. A third regulatory activity, the Trachealess transcription factor, is also required to establish the identity of the preduct cells, but we show that it acts independently or downstream from the DER:fork head confrontation. In trachealess mutants, subdivision of the salivary primordium occurs normally and the dorsal cells form glands, but the ventral cells are undetermined. We present a model proposing that trachealess is the crucial duct-specific gene that Fork head represses to distinguish pregland from preduct cells.

Related Papers

• → Transcription Factors WOX11/12 Directly Activate WOX5/7 to Promote Root Primordia Initiation and Organogenesis(2016)279 cited
• → Photoinduction of Flower Identity in Vegetatively Biased Primordia(1998)52 cited
• → Developmental programmes in floral organ formation(2001)24 cited
• → DEVELOPMENTAL POTENTIALITIES OF LEAF PRIMORDIA OF OSMUNDA CINNAMOMEA: THE INFLUENCE OF DETERMINED LEAF PRIMORDIA ON UNDETERMINED LEAF PRIMORDIA(1967)14 cited