title: Salivary gland gene expression atlas identifies a new regulator of branching morphogenesis.
abstract: During organ development, local changes in gene expression govern morphogenesis and cell fate. We have generated a microanatomical atlas of epithelial gene expression of embryonic salivary glands. The mouse submandibular salivary gland first appears as a single mass of epithelial cells surrounded by mesenchyme, and it undergoes rapid branching morphogenesis to form a complex secretory organ with acini connected to an extensive ductal system. Using laser capture microdissection, we collected samples from 14 distinct epithelial locations at embryonic days 12.5, 13.5, 14, and 15, and characterized their gene expression by microarray analysis. These microarray results were evaluated by qPCR of biological replicates and by comparisons of the gene expression dataset with published expression data. Using this gene expression atlas to search for novel regulators of branching morphogenesis, we found a substantial reduction in mRNA levels of GSK3β at the base of forming clefts. This unexpected finding was confirmed by immunostaining, and inhibition of GSK3β activity enhanced salivary gland branching. This first microanatomical expression atlas of a developing gland characterizes changes in local gene expression during salivary gland development and differentiation, which should facilitate the identification of key genes involved in tissue morphogenesis.
authors.affiliation: Cell Biology Section, Laboratory of Cell and Developmental Biology, Division of Intramural Research, National Institute of Dental and Craniofacial Research, 30 Convent Drive, MSC 4370, Bethesda, MD 20892, USA. kurt.musselmann@gmail.com
authors.forename: K
authors.initials: K
authors.lastname: Musselmann
authors.forename: J A
authors.initials: JA
authors.lastname: Green
authors.forename: K
authors.initials: K
authors.lastname: Sone
authors.forename: J C
authors.initials: JC
authors.lastname: Hsu
authors.forename: I R
authors.initials: IR
authors.lastname: Bothwell
authors.forename: S A
authors.initials: SA
authors.lastname: Johnson
authors.forename: J S
authors.initials: JS
authors.lastname: Harunaga
authors.forename: Z
authors.initials: Z
authors.lastname: Wei
authors.forename: K M
authors.initials: KM
authors.lastname: Yamada
mesh_terms: D000818:Animals; D002874:Chromosome Mapping; D030541:Databases, Genetic; D015536:Down-Regulation; D004847:Epithelial Cells / Q000502:physiology; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D038362:Glycogen Synthase Kinase 3 / Q000235:genetics / Q000502:physiology*; D000071679:Glycogen Synthase Kinase 3 beta; D051379:Mice; D008813:Mice, Inbred ICR; D042282:Microdissection / Q000379:methods; D020411:Oligonucleotide Array Sequence Analysis; D009924:Organ Culture Techniques; D038081:Organogenesis / Q000235:genetics*; D015398:Signal Transduction; D013363:Submandibular Gland / Q000196:embryology*
chemical_list: D000071679:Glycogen Synthase Kinase 3 beta; C000605507:Gsk3b protein, mouse; D038362:Glycogen Synthase Kinase 3