Structural analysis of mouse tenascin-X: evolutionary aspects of reduplication of FNIII repeats in the tenascin gene family.
Tenascin-X (TNX) is an extracellular matrix glycoprotein involved in both primary structural functions and modulating cellular activities in multicellular organisms. We determined the 67977bp nucleotide sequence of the entire mouse tenascin-X (Tnx) gene, which also includes the last exon of Creb-rp and Cyp21. We compared it with the orthologous human locus. Conservation of both position and orientation of the three functionally unrelated genes at this position was found. Comparison also revealed that introns 1, 4 and 6 of Tnx are highly conserved between species. The sequence showed that mouse Tnx contains 43 exons separated by 42 introns. The deduced amino-acid sequence (4114 residues) revealed that mouse Tnx has a primary structure characteristic of tenascins, which consists of a signal peptide and four heptad repeats followed by 18.5 epidermal growth factor-like (EGF) repeats, 31 fibronectin type III-like (FNIII) repeats, and a region homologous to fibrinogen. cDNA clones generated by alternative splicing of eight consecutive FNIII repeats (M15-M22) as well as a proximal FNIII repeat (M3) were also identified. The FNIII motifs that were subject to alternative splicing were assigned to the group of recently reduplicated FNIII repeats because they have a high level of amino-acid sequence similarity. We also analyzed the evolution of FNIII repeats in TNX.
Ikuta
T
T
Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Hokkaido 060-0812, Japan.
Sogawa
N
N
Ariga
H
H
Ikemura
T
T
Matsumoto
K
K
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D017124:Conserved Sequence; D003433:Crosses, Genetic; D019143:Evolution, Molecular; D005091:Exons; D020440:Gene Duplication; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008969:Molecular Sequence Data; D010802:Phylogeny; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013234:Stem Cells / Q000378:metabolism; D019063:Tenascin / Q000737:chemistry / Q000235:genetics*; D014157:Transcription Factors / Q000378:metabolism
D020033:Protein Isoforms; D019063:Tenascin; D014157:Transcription Factors; C081865:tenascin X