Evidence For the Presence of A Cdc2-Like Protein Kinase In the Dinoflagellate Crypthecodinium Cohnii |
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Authors: | MARIVONNE RODRIGUEZ JEONG W. CHO HELMUT W. SAUER PETER J. RIZZO |
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Affiliation: | Department of Biology, Texas A&M University, College Station, Texas 77843-3258 |
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Abstract: | ABSTRACT. The unusual nature of mitosis and ancestral organization of the dinoflagellate nucleus prompted the question of whether the cdc 2-like histone H1 kinase, a presumed ubiquitous cell cycle regulator in eukaryotes, is present in these primitive organisms. Western blotting of Crypthecodinium cohnii protein extracts using antibody against the Pro-Ser-Thr-Ala-Ile-Arg-Glu (=PSTAIRE) amino acid sequence motif, conserved in all cdc 2 homologues known, revealed one prominent band corresponding to a protein with an apparent relative molecular weight ≈ 34,000, identical in mobility to that from HeLa cells and Physarum polycephalum , higher and lower eukaryotic controls, respectively. Incubation of C. cohnii cell lysates with p13 suc 1-sepharose beads, which preferentially, though not exclusively, bind p34 cdc 2, resulted in precipitation of a 34-kDa protein which was reactive with anti-PSTAIRE antibody, selectively competed for by the PSTAIRE peptide and able to phosphorylate histone H1 in vitro. We conclude that the dinoflagellate C. cohnii contains a protein very similar to the cdc 2 gene product from fission yeast and its homologues in all eukaryotes studied thus far. |
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Keywords: | Cell cycle regulation mitosis p13suc1 protein precipitation p34cdc2 protein kinase Pyrrophyta |
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