Cyclin B (p56cdc13) localization in the yeast Schizosaccharomyces pombe: An ultrastructural and immunocytochemical study |
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Authors: | Muriel Audit Michle Barbier Marie-Odile Soyer-Gobillard Marie Albert Marie-Line Graud Gisle Nicolas Guy Lenaers |
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Institution: | Muriel Audit,Michèle Barbier,Marie-Odile Soyer-Gobillard,Marie Albert,Marie-Line Géraud,Gisèle Nicolas,Guy Lenaers |
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Abstract: | Summary— The eucaryote cell cycle is driven by a set of cyclin dependent kinases (CDKs) associated to cyclins, which confer not only the activity but also the substrate specificity and the proper localization of the kinase activity. In the fission yeast Schizosaccharomyces pombe, only one cyclin, the product of the cdc13 gene (p56cdc13), is required to be associated with p34cdc2, to control the complete cell cycle. Earlier studies have localized this complex mainly in the nucleus and its periphery. Using new improved electron microscopy (EM) technologies, based on high pressure freezing fixation, we refined previous studies, evidencing cytoplasmic localization of p56cdc13, in addition to the nuclear localization previously observed. Further immunofluorescence studies, performed on aldehydically fixed cells, confirmed our EM results, emphasizing the major cytoplasmic localization of p56cdc13 in interphase cells and the relocalization towards the nucleus in mitotic cells, suggesting that the S pombe cyclin B localization is cell cycle-regulated. |
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Keywords: | cyclin B (p56cdc13) localization Schizosaccharomyces pombe high pressure freezing fixation aldehydic fixation |
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