1997 Fiscal Year Final Research Report Summary
Expression and function of laminin isoforma during organogenesis
| Project/Area Number |
08670033
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
General anatomy (including Histology/Embryology)
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| Research Institution | KITASATO UNIVERSITY |
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Principal Investigator |
KADOYA Yuichi Kitasato Univ.School of Medicine Research Associate, 医学部, 助手 (10185887)
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| Project Period (FY) |
1996 – 1997
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| Keywords | basement membrane / laminin alpha2 / laminin-1 / morphogenesis / organ culture / synthetic peptide / submandibular gland / salivary gland |
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| Research Abstract |
Active sequences from the laminin alpha1 and alpha2 chain carboxyl-terminal globular domains (Gdomain)have been identified by screening overlapping synthetic peptides in a number of biological assays (Nomizu et al., J.Biol.Chem.270 : 20583-20590,1995 ; Nomizu et al., FEBS Lett.396 : 37-42,1996). We have tested the activity of these peptides in submandibular gland explants of embryonic day-13 mice to determine the functional sites involved in organ development. The laminin alpha1 chain peptide, RKRLQVQLSIRT (residues 2719-2730-and designated AG-73), significantly inhibited epithelial branching morphogenesis. In contrast, other cell adhesive laminin alpha1 chain peptides including the AASIKVAVSADR and NRWHSIYITRFG failed to inhibit the branching. MG-73, a homologue of AG-73 from the laminin alpha2 chain, did not inhibit the branching. The alpha2 chain peptide had no effect, which may be due to the low levels of this laminin chain in embryonic day 13 submandibular gland. Laminin alpha2 chain-specific monoclocal antibodies strongly reacted with the basement membranes of developed acini but only weakly stained embryonic day 13 submandibular epithelial basement membrane. The expression of E-cadherin and alpha6 integrin, as detected by immunofluorescence, were unchanged in both AG-73 and control scramble peptide treated epithelial cells of the explants. In contrast, immunostaining of nidogen/entactin showed that explants treated with AG-73 for 3 days had a discontinuous basement membrane. Explants treated for 3 days with control peptide showed a normal basement membrane. These results suggest that the region containing the AG-73 sequence of the laminin alpha1 chain is crucial for development of submandibular gland at early embryonic stages. The discontinuous basement membrane in AG-73-treated explants may indicate an important role for this region in basement membrane assembly.
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