Expression profiles of the duplicated matrix metalloproteinase-9 genes suggest their different roles in apoptosis of larval intestinal epithelial cells during Xenopus laevis metamorphosis.
Matrix metalloproteinases (MMPs) play a pivotal role in development and/or pathogenesis through degrading extracellular matrix (ECM) components. We have previously shown that Xenopus MMP-9 gene is duplicated. To assess possible roles of MMP-9 and MMP-9TH in X. laevis intestinal remodeling, we here analyzed their expression profiles by in situ hybridization and show that their expression is transiently up-regulated during thyroid hormone-dependent metamorphosis. Of interest, MMP-9TH mRNA is strictly localized in the connective tissue and most highly expressed just beneath the larval epithelium that begins to undergo apoptosis. On the other hand, cells expressing MMP-9 mRNA become first detectable in the connective tissue and then, after the start of epithelial apoptosis, also in the larval epithelium. These results strongly suggest that MMP-9TH is responsible in the larval epithelial apoptosis through degrading ECM components in the basal lamina, whereas MMP-9 is involved in the removal of dying epithelial cells during amphibian intestinal remodeling.
Hasebe
Takashi
T
Department of Biology, Nippon Medical School, Nakahara-ku, Kawasaki, Kanagawa, Japan.
Kajita
Mitsuko
M
Fujimoto
Kenta
K
Yaoita
Yoshio
Y
Ishizuya-Oka
Atsuko
A
D000818:Animals; D017209:Apoptosis; D004625:Embryo, Nonmammalian; D004847:Epithelial Cells; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D007422:Intestines; D007814:Larva / Q000166:cytology*; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000502:physiology*; D008675:Metamorphosis, Biological / Q000235:genetics*; D014982:Xenopus laevis / Q000502:physiology*
D020780:Matrix Metalloproteinase 9