title: cimp1, a novel astacin family metalloproteinase gene from East African cichlids, is differentially expressed between species during growth.
abstract: Lake Victoria cichlid fishes are excellent examples of explosive adaptive radiation. Although Lake Victoria cichlids are believed to have arisen during a short period (approximately 14,000 years), they have various species-specific phenotypes. One important phenotype that distinguishes each species is the shape of the jaw, which has diverged to adapt to the wide variety of trophic habitats present in the lake. Here we demonstrate a new approach to investigate the diversification of cichlid jaw morphology at the genetic level by examining differentially expressed genes. We used a DNA chip to compare gene expression levels between closely related cichlid fishes. This analysis indicated that the expression of some genes differed in the larvae of two cichlid species. One such clone encodes a new astacin family metalloproteinase. The expression level of the isolated gene, named cimp1, was analyzed in more detail by real-time quantitative reverse transcription-polymerase chain reaction. A significant difference in cimp1 expression was observed between two Haplochromis cichlid species during development. Using in situ hybridization, we found that this gene is expressed only in head and gill epithelia. Biochemical analysis showed that cichlid metalloproteinase 1 (CiMP1) has proteolytic activity, a common attribute of all astacin family proteins. Because some astacin family proteins contribute to morphogenesis in animals, CiMP1 is expected to participate in species-specific head morphogenesis in cichlids. This is the first study to demonstrate that differentially expressed genes among cichlids can be identified using a DNA chip.
authors.affiliation: Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259-B21 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Teiya
authors.initials: T
authors.lastname: Kijimoto
authors.forename: Masakatsu
authors.initials: M
authors.lastname: Watanabe
authors.forename: Koji
authors.initials: K
authors.lastname: Fujimura
authors.forename: Masumi
authors.initials: M
authors.lastname: Nakazawa
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Murakami
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kuratani
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kohara
authors.forename: Takashi
authors.initials: T
authors.lastname: Gojobori
authors.forename: Norihiro
authors.initials: N
authors.lastname: Okada
mesh_terms: D000349:Africa; D000595:Amino Acid Sequence; D000818:Animals; D023681:Cichlids / Q000235:genetics* / Q000254:growth & development; D004848:Epithelium / Q000254:growth & development; D005786:Gene Expression Regulation / Q000502:physiology*; D005880:Gills / Q000254:growth & development*; D008666:Metalloendopeptidases / Q000235:genetics*; D008969:Molecular Sequence Data; D009024:Morphogenesis / Q000235:genetics*; D010802:Phylogeny; D013045:Species Specificity
chemical_list: D008666:Metalloendopeptidases; C071288:astacin