Int J Biol Sci 2006; 2(3):125-132. doi:10.7150/ijbs.2.125 This issue Cite
1. Laboratoire de Biologie Moléculaire de la Cellule, UMR 5161 CNRS/ENS de Lyon, Ecole Normale Supérieure de Lyon, IFR128 BioSciences Lyon-Gerland, 46, Allée d'Italie, 69364 Lyon Cedex 07, France.
2. Laboratoire Arago, UMR 7628, CNRS and University Pierre and Marie Curie, BP 44, F-66651 Banyuls sur Mer, France.
3. Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093, USA
The proprotein convertases (PCs) comprise a family of subtilisin-like endoproteases that activate precursor proteins (including, prohormones, growth factors, and adhesion molecules) during their transit through secretory pathways or at the cell surface. To explore the evolution of the PC gene family in chordates, we made a phylogenetic analysis of PC genes found in databases, with special attention to three PC genes of the cephalochordate amphioxus, the closest living invertebrate relative to the vertebrates. Since some vertebrate PC genes are essential for early development, we investigated the expression pattern of the C isoform of the amphioxus PC6 gene (aPC6C). In amphioxus embryos and larvae, aPC6C is expressed at places where epithelia fuse. Several kinds of fusions occur: ectoderm-to-ectoderm during neurulation; mesoderm-to-ectoderm during formation of the preoral ciliated pit; and endoderm-to-ectoderm during formation of the mouth, pharyngeal slits, anus, and external opening of the club-shaped gland. Presumably, at all these sites, aPC6C is activating proteins favoring association between previously disjunct cell populations.
Keywords: amphioxus, gene expression pattern, prohormone convertases, PC6