Study on Branch-specific Genes in Mouse Salivary Gland Morphogenesis

Research Project

Project/Area Number	13640660
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	生物形態・構造
Research Institution	Chiba University
Principal Investigator	NOGAWA Hiroyuki Chiba Univ., Fac. Science, Associate Prof., 理学部, 助教授 (40143250)
Project Period (FY)	2001 – 2002
Project Status	Completed (Fiscal Year 2002)
Budget Amount *help	¥2,500,000 (Direct Cost: ¥2,500,000) Fiscal Year 2002: ¥700,000 (Direct Cost: ¥700,000) Fiscal Year 2001: ¥1,800,000 (Direct Cost: ¥1,800,000)
Keywords	Mouse / Salivary Gland / Branching Morphogenesis / Mesenchyme-free Culture / Growth Factors / Branch-specific Genes / Subtraction Screening
Research Abstract	To understand the mechanisms of salivary branching morphogenesis at the molecular level, we searched the genes which were specifically involved in epithelial branching morphogenesis. When mouse salivary epithelium was cultured in the absence of mesenchyme in vitro, a combination of EGF and horse serum induced epithelial branching, but FGF induced epithelial elongation without branching. The genes differentially expressed between these distinct groups were screened by the subtraction method. After cloning and sequencing, the 9 genes were detected highly expressed in the branching epithelium in vitro. Next, it was examined whether these genes were expressed in correlation to branching morphogenesis in vivo as well as in vitro. The normal E13-day and E14-day salivary rudiments were separated into the distal lobular part (branching) and the proximal stalk part (non-branching), and the transcripts of the genes in each part were estimated by the semi-quantitative RT-PCR technique. The results however showed that none of them were more highly expressed in the lobular part than in the stalk part, suggesting that the genes selected in vitro might not be specifically involved in branching morphogenesis in vivo. It remains to be solved whether salivary branching morphogenesis is achieved under the control of some specific genes.