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EGF‐dependent lobule formation and FGF7‐dependent stalk elongation in branching morphogenesis of mouse salivary epithelium in vitro
Author(s) -
Morita Kuniharu,
Nogawa Hiroyuki
Publication year - 1999
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/(sici)1097-0177(199906)215:2<148::aid-dvdy7>3.0.co;2-v
Subject(s) - biology , morphogenesis , epithelium , microbiology and biotechnology , mesenchyme , fibroblast growth factor , elongation , epidermal growth factor , stalk , fgf10 , explant culture , anatomy , in vitro , cell culture , embryo , biochemistry , receptor , genetics , materials science , ultimate tensile strength , gene , horticulture , metallurgy
When supplemented with appropriate growth factors, salivary gland epithelial explants isolated from mouse embryos undergo branching morphogenesis in vitro in the absence of mesenchyme. Epidermal growth factor (EGF) induces lobule formation, while fibroblast growth factor 7 (FGF7) promotes stalk elongation. A mixture of EGF and FGF7 produces an intermediate morphology, which resembles the branching pattern of salivary epithelium observed in vivo. To investigate how lobule formation and stalk elongation are related to the pattern of epithelial cell proliferation induced by EGF and FGF7, we performed a bromodeoxyuridine labeling study in whole‐mount preparations. During the initial steps of lobule formation in EGF cultures, cleft and non‐cleft regions had similar proliferative activity. However, once clefts had fully deepened, cells with low proliferative activity appeared at the bottom of the clefts. In contrast, during stalk elongation in FGF7 cultures, distal regions of the explants always showed higher proliferative activity than proximal regions. These results suggest that stalk elongation, but not cleft formation, may result from differential cell proliferation. Dev Dyn 1999;215:148–154 . © 1999 Wiley‐Liss, Inc.