A dinoflagellate CDK5-like cyclin-dependent kinase.
BACKGROUND
Mitosis during the dinoflagellate cell cycle is unusual in that the nuclear envelope remains intact and segregation of the permanently condensed chromosomes uses a cytoplasmic mitotic spindle. To examine regulation of the dinoflagellate cell cycle in the context of these unusual nuclear features, it is necessary to isolate and characterize cell cycle regulators such as CDK (cyclin-dependent kinase).


RESULTS
We report the characterization of a CDK from the dinoflagellate Lingulodinium polyedrum. This CDK reacts with an anti-PSTAIRE antibody and was identified by protein microsequencing after partial purification. The protein microsequence shows homology toward the Pho85/CDK5 clade of CDKs. Neither the amount nor the phosphorylation state changed over the course of the cell cycle, in agreement with results reported for CDK5 family members in other systems.


CONCLUSIONS
We conclude we have probably isolated a dinoflagellate CDK5-like protein. The data reported here support the identification of this protein as a CDK5 homologue, and suggest that dinoflagellates may contain several CDK families.
Bertomeu
Thierry
T
Institut de Recherche en Biologie Végétale, Département de Sciences Biologiques, Université de Montréal, Montréal, Québec, Canada.
Rivoal
Jean
J
Morse
David
D
D000818:Animals; D015153:Blotting, Western; D002453:Cell Cycle; D051360:Cyclin-Dependent Kinase 5 / Q000737:chemistry* / Q000145:classification / Q000302:isolation & purification; D018844:Cyclin-Dependent Kinases / Q000737:chemistry; D004141:Dinoflagellida / Q000737:chemistry*; D005434:Flow Cytometry; D010802:Phylogeny; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry; D017385:Sequence Homology
D029701:Saccharomyces cerevisiae Proteins; D051360:Cyclin-Dependent Kinase 5; D018844:Cyclin-Dependent Kinases; C058605:PHO85 protein, S cerevisiae