Amino acid sequence of mouse tenascin and differential expression of two tenascin isoforms during embryogenesis.
We have isolated cDNA clones for mouse tenascin and analyzed expression of tenascin mRNAs during embryonic development of the kidney and gut. The deduced amino acid sequence of the mouse tenascin cDNAs shows a modular structure of repeats similar to chicken and human tenascin. In mouse there are 14.5 cysteine-rich repeats with similarity to the EGF repeat, followed by several repeats with similarity to the type III repeat of fibronectin. A longer variant contains 13 fibronectin type III repeats, whereas a shorter splice variant of mouse tenascin lacks the 5 type III repeats that occur directly after the fifth repeat in the longer variant. Contrary to the chicken and human sequences, mouse tenascin does not contain an RGD sequence in the third type III repeat implicated in cell attachment, or in any other positions. In Northern hybridizations to RNA from primary embryonic fibroblasts, the cDNA clone M 20/1 detects two mRNAs with sizes close to 6 and 8 kb. This, and the other data presented here suggest that the two major mouse tenascin polypeptides arise through an alternative RNA splicing. The two major mRNAs are differentially expressed during development. The 8-kb mRNA is more prominent than the 6-kb mRNA throughout prenatal kidney development, but during postnatal development the ratio of the two mRNAs changes. A different expression pattern is seen in the developing gut where the 6-kb mRNA predominates during embryogenesis with the 8-kb mRNA appearing later. The mRNA data of the developing gut correspond with previous protein data, which showed that the shorter Mr 210,000 polypeptide predominates during earlier developmental stages and the larger Mr 260,000 polypeptide appears later in the embryonic gut (Aufderheide, E., and P. Ekblom. 1988. J. Cell Biol. 107:2341-2349).
Friedrich-Miescher-Laboratorium der Max-Planck-Gesellschaft, Tübingen, Germany.
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Weller
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Beck
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Ekblom
D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D015816:Cell Adhesion Molecules, Neuronal / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D005314:Embryonic and Fetal Development / Q000235:genetics; D004815:Epidermal Growth Factor / Q000737:chemistry / Q000235:genetics; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D005353:Fibronectins / Q000737:chemistry / Q000235:genetics; D005786:Gene Expression Regulation; D006031:Glycosylation; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000196:embryology* / Q000254:growth & development; D007668:Kidney / Q000196:embryology* / Q000254:growth & development / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009842:Oligopeptides; D021382:Protein Sorting Signals / Q000737:chemistry / Q000235:genetics; D012326:RNA Splicing; D012091:Repetitive Sequences, Nucleic Acid; D012689:Sequence Homology, Nucleic Acid; D019063:Tenascin
D015816:Cell Adhesion Molecules, Neuronal; D016326:Extracellular Matrix Proteins; D005353:Fibronectins; D009842:Oligopeptides; D021382:Protein Sorting Signals; D019063:Tenascin; D004815:Epidermal Growth Factor; C047981:arginyl-glycyl-aspartic acid