Molecular cloning of matrin 3. A 125-kilodalton protein of the nuclear matrix contains an extensive acidic domain.
We report here the cloning and sequencing of matrin 3, an acidic internal matrix protein, from a rat insuloma cDNA library. The nucleotide sequence has a single open reading frame encoding a polypeptide of 845 amino acids. The Genbank and National Biomedical Research Foundation databases did not contain any sequences similar to that of matrin 3. The primary structure consists of 33% charged residues and is generally hydrophilic. The amino-terminal region (residues 1-120) is positively charged and contains a large number of amino acids with free hydroxyl groups (26 of the first 100 residues) as in the lamins and several non-lamin intermediate filament proteins. A highly acidic domain (approximately 170 amino acids) near the carboxyl terminus, in which 32% of the amino acid residues are acidic (Glu or Asp), is a characteristic found in other nuclear proteins (Earnshaw, W. C. (1987) J. Cell Biol. 105, 1479-1482). A putative nuclear targeting signal sequence (Ser-Lys-Lys-Lys-Leu-Lys-Lys-Val-Glu) is located in the middle of the highly acidic domain. The corresponding human deduced partial amino acid sequence is 96% identical to the rat sequence, indicating that matrin 3 is a highly conserved protein.
Belgrader
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Department of Biological Sciences, State University of New York, Buffalo 14260.
Dey
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Berezney
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D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies; D034961:Antigens, Nuclear; D001483:Base Sequence; D015152:Blotting, Northern; D015153:Blotting, Western; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D005455:Fluorescent Antibody Technique; D006367:HeLa Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D012333:RNA, Messenger / Q000032:analysis; D016601:RNA-Binding Proteins; D051381:Rats; D012689:Sequence Homology, Nucleic Acid; D014407:Tumor Cells, Cultured
D000906:Antibodies; D034961:Antigens, Nuclear; D009687:Nuclear Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; C068873:matrin 3, rat; D004247:DNA