J. Biochem, 2003, Vol. 134, No. 3 385-394
© 2003 Japanese Biochemical Society
BIOCHEMISTRY |
Differential Expression of Two Cathepsin Es during Metamorphosis-Associated Remodeling of the Larval to Adult Type Epithelium in Xenopus Stomach
1 Life Science Institute, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554; 2 Department of Biology, Faculty of Education, Utsunomiya University, 350 Mine, Utsunomiya 321-8505; and 3 Department of Biochemistry, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo 173-0015
Cathepsin E (CE) was purified from the foregut of Xenopus laevis tadpoles as a mature dimeric form. The purified enzyme was a typical CE among aspartic proteinases with respect to pH dependence of proteolytic activity, susceptibility to pepstatin, and having N-linked high-mannose type oligosaccharide chains. We isolated two cDNAs for the CE (CE1 and CE2) from adult stomach. The amino acid sequence of the N-terminal region of the purified CE coincided with the corresponding sequence predicted from CE1. Northern blot analysis and in situ hybridization were performed. The CE1 mRNA was highly expressed in surface mucous cells and gland cells constituting the larval epithelium of the foregut of pro-metamorphic tadpoles. As metamorphosis began and progressed, CE1 mRNA drastically decreased in amount, and subsequently both CE1 and CE2 mRNAs gradually increased. The increase in CE2 mRNA was detected shortly after the increase in CE1 mRNA. The decrease in CE1 expression correlated with degeneration of the larval type epithelium, while the increases in both CE1 and CE2 expression correlated with formation of the adult type epithelium. Thus, cathepsin E gene expression was differentially regulated during metamorphosis-associated remodeling of the larval to adult type epithelium in stomach.
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