Nuclear NonO/p54nrb Protein Is a Nonclassical Carbonic Anhydrase
Copyright policy )Nuclear NonO/p54nrb Protein Is a Nonclassical Carbonic Anhydrase
The growing carbonic anhydrase (CA) gene family includes 11 enzymatically active isozymes in mammals. Each of them has a characteristic cellular and subcellular distribution pattern. In this report, we demonstrate for the first time a nuclear protein with CA activity. A polypeptide recognized by CA II antibodies was purified from several rat tissues using CA inhibitor affinity chromatography. This polypeptide of apparent 66 kDa mass was characterized using amino acid sequencing and CA activity measurements. It appeared to be identical to nonO/p54(nrb), a previously cloned and characterized RNA and DNA binding nuclear factor. Recombinant nonO generated in baculovirus bound to the CA inhibitor affinity chromatography matrix and revealed detectable CA activity (25 units/mg). Hansson's histochemical staining of rat lymph nodes followed by light and electron microscopy showed nuclear CA activity in lymphocytes, suggesting that the nuclear nonO protein is catalytically active in vivo. These results demonstrate that a previously known transcription factor is a novel, nonclassical CA. Through its CA activity, the nonO may function in the maintenance of pH homeostasis in the nucleus.
- The University of Texas at Austin United States
- University of Mary United States
- University of Oulu Finland
- Saint Louis University United States
- Oulu University Hospital Finland
Male, Blotting, Western, Nuclear Proteins, RNA-Binding Proteins, Hydrogen-Ion Concentration, Immunohistochemistry, Chromatography, Affinity, Recombinant Proteins, Rats, DNA-Binding Proteins, Isoenzymes, Microscopy, Electron, Nuclear Matrix-Associated Proteins, Sequence Analysis, Protein, Testis, Tumor Cells, Cultured, Animals, Octamer Transcription Factors, Lymph Nodes, Carbonic Anhydrases
Male, Blotting, Western, Nuclear Proteins, RNA-Binding Proteins, Hydrogen-Ion Concentration, Immunohistochemistry, Chromatography, Affinity, Recombinant Proteins, Rats, DNA-Binding Proteins, Isoenzymes, Microscopy, Electron, Nuclear Matrix-Associated Proteins, Sequence Analysis, Protein, Testis, Tumor Cells, Cultured, Animals, Octamer Transcription Factors, Lymph Nodes, Carbonic Anhydrases
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