The Structure and Function of Retinal Pigment Epithelial Cells

1996 Fiscal Year Final Research Report Summary

• Project/Area Number: 07457003
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: General anatomy (including Histology/Embryology)
• Research Institution: The University of Tokyo
• Principal Investigator: HIROSAWA Kazushige The University of Tokyo, INSTITUTE OF MEDICAL SCIENCE,PROFESSOR, 医科学研究所, 教授 (30009980)
• Co-Investigator(Kenkyū-buntansha): SAGARA Hiroshi The University of Tokyo, INSTITUTE OF MEDICAL SCIENCE,PROFESSOR, 医科学研究所, 助手 (50145041)
• Project Period (FY): 1995 – 1996
• Keywords: retinal pigment epithelium / monoclonal antibody / EMMPRIN / Muller cell / immunoglobulin superfamily

Research Abstract

Monoclonal antibodies were raised against chick and bovine retinal pigment epithelial (RPE) cells using mice as immune animal. Among the monoclonal antibodies, S5D8 and RPE7 were analyzed their characters by means of molecular and cellular biological methods.
1) ; S5D8 : The antgen protein has molecular weight of 63kDa. The whole length of cDNA is 2510bp, open reading frame being 1599bp with 2 olyadenylation signals. Amino acid residues are 533 and their molecular size being 60.9kDa. The protein has 3 glycosylation sites. It has neither signal peptide nor membrane expanding region. The size of mRNA is about 2.9kbases. The open reading frame was transfected to cultured fibroblasts, the endoplasmic reticula of which were stained with S5D8.
2) ; PRE7 : The localization of RPE7 was on the plasma membranes of RPE and Muller cells of neural retina. This result seem to suggest the protein RPE7 is involved in the supporting function of the retina. The protein has molecular weight of 40-45kDa by Western blotting. RPE7 has an open reading frame of 271 amino acid residues, 3 glycosylation sitesand is found to have a membrane expanding hydrophobic region. Homology research of this cDNA sequences revealed that RPE7 protein belongs to a novel type of immunoglobulin superfamily, one of which has been named EMMPRIN.EMMPRIN is involved in the remodeling of extrcellular matrix and plays a role in the metastasis of cancer cells. Metalloproteinase activity was assayd with cultured bovine RPE by zymography. The culture supernatant contained gelatinaseA,the activity of which became higher when anti-RPE7 antibody was added to the culture medium. It is concluded, from this result, that RPE7 plays an important role in the phagocytosis of outer segment and mobilization of RPE at some pathlogical conditions.