title: Progenitor outgrowth from the niche in Drosophila trachea is guided by FGF from decaying branches.
abstract: Although there has been progress identifying adult stem and progenitor cells and the signals that control their proliferation and differentiation, little is known about the substrates and signals that guide them out of their niche. By examining Drosophila tracheal outgrowth during metamorphosis, we show that progenitors follow a stereotyped path out of the niche, tracking along a subset of tracheal branches destined for destruction. The embryonic tracheal inducer branchless FGF (fibroblast growth factor) is expressed dynamically just ahead of progenitor outgrowth in decaying branches. Knockdown of branchless abrogates progenitor outgrowth, whereas misexpression redirects it. Thus, reactivation of an embryonic tracheal inducer in decaying branches directs outgrowth of progenitors that replace them. This explains how the structure of a newly generated tissue is coordinated with that of the old.
authors.affiliation: Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305-5307, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: Chen
authors.forename: Mark A
authors.initials: MA
authors.lastname: Krasnow
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology*; D004331:Drosophila melanogaster / Q000196:embryology*; D005346:Fibroblast Growth Factors / Q000235:genetics / Q000502:physiology*; D055785:Gene Knockdown Techniques; D008675:Metamorphosis, Biological; D017468:Receptors, Fibroblast Growth Factor / Q000235:genetics / Q000502:physiology; D055153:Stem Cell Niche / Q000502:physiology*; D014132:Trachea / Q000196:embryology*
chemical_list: D029721:Drosophila Proteins; D017468:Receptors, Fibroblast Growth Factor; C102644:bnl protein, Drosophila; D005346:Fibroblast Growth Factors