title: Transcriptional regionalization of the fruit fly's airway epithelium.
abstract: Although airway epithelia are primarily devoted to gas exchange, they have to fulfil a number of different tasks including organ maintenance and the epithelial immune response to fight airborne pathogens. These different tasks are at least partially accomplished by specialized cell types in the epithelium. In addition, a proximal to distal gradient mirroring the transition from airflow conduction to real gas exchange, is also operative. We analysed the airway system of larval Drosophila melanogaster with respect to region-specific expression in the proximal to distal axis. The larval airway system is made of epithelial cells only. We found differential expression between major trunks of the airways and more distal ones comprising primary, secondary and terminal ones. A more detailed analysis was performed using DNA-microarray analysis to identify cohorts of genes that are either predominantly expressed in the dorsal trunks or in the primary/secondary/terminal branches of the airways. Among these differentially expressed genes are especially those involved in signal transduction. Wnt-signalling associated genes for example are predominantly found in secondary/terminal airways. In addition, some G-protein coupled receptors are differentially expressed between both regions of the airways, exemplified by those activated by octopamine or tyramine, the invertebrate counterparts of epinephrine and norepinephrine. Whereas the OAMB is predominantly found in terminal airway regions, the oct3βR has higher expression levels in dorsal trunks. In addition, we observed a significant association of both, genes predominantly expressed in dorsal trunks or in primary to terminal branches branches with those regulated by hypoxia. Taken together, this observed differential expression is indicative for a proximal to distal transcriptional regionalization presumably reflecting functional differences in these parts of the fly's airway system.
authors.affiliation: University of Kiel, Dept. Molecular Physiology, Kiel, Germany.
authors.forename: Muhammad N
authors.initials: MN
authors.lastname: Faisal
authors.affiliation: University of Kiel, Dept. Molecular Physiology, Kiel, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Hoffmann
authors.affiliation: University of Kiel, Dept. Molecular Physiology, Kiel, Germany.
authors.forename: Samar
authors.initials: S
authors.lastname: El-Kholy
authors.affiliation: University of Kiel, Dept. Molecular Physiology, Kiel, Germany; Research Center Borstel, Priority Area Allergy and Asthma, Borstel, Germany.
authors.forename: Kimberley
authors.initials: K
authors.lastname: Kallsen
authors.affiliation: Research Center Borstel, Priority Area Allergy and Asthma, Borstel, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Wagner
authors.affiliation: Bernhard-Nocht Institute for Tropical Medicine, Dept. Molecular Parasitology, Hamburg, Germany.
authors.forename: Iris
authors.initials: I
authors.lastname: Bruchhaus
authors.affiliation: University of Kiel, Dept. Molecular Physiology, Kiel, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Fink
authors.affiliation: University of Kiel, Dept. Molecular Physiology, Kiel, Germany; German Center for Lung Research (DZL), Airway Research Center North (ARCN), Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Roeder
mesh_terms: D000818:Animals; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics* / Q000254:growth & development; D004848:Epithelium / Q000378:metabolism; D015870:Gene Expression; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D007814:Larva / Q000033:anatomy & histology / Q000235:genetics / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism; D012137:Respiratory System / Q000378:metabolism; D015398:Signal Transduction; D060449:Wnt Signaling Pathway
chemical_list: D029721:Drosophila Proteins; D043562:Receptors, G-Protein-Coupled