Casein Kinase II Is Required for Cell Cycle Progression during G and G/M in Saccharomyces cerevisiae

doi:10.1074/jbc.270.43.25905

Casein Kinase II Is Required for Cell Cycle Progression during G and G/M in Saccharomyces cerevisiae(*)

From the Department of Biochemistry and Molecular Biology, The University of Georgia, Athens, Georgia 30602-7229

^§To whom correspondence should be addressed. Tel.: 706-542-1769; Fax: 706-542-1738; glover{at}bscr.uga.edu.

Abstract

The catalytic subunit of Saccharomyces cerevisiae casein kinase II (Sc CKII) is encoded by the CKA1 and CKA2 genes, which together are essential for viability. Five independent temperature-sensitive alleles of the CKA2 gene were isolated and used to analyze the function of CKII during the cell cycle. Following a shift to the nonpermissive temperature, cka2 strains arrested within a single cell cycle and exhibited a dual arrest phenotype consisting of 50% unbudded and 50% large-budded cells. The unbudded half of the arrested population contained a single nucleus and a single focus of microtubule staining, consistent with arrest in G. Most of the large-budded fraction contained segregated chromatin and an extended spindle, indicative of arrest in anaphase, though a fraction contained an undivided nucleus with a short thick intranuclear spindle, indicative of arrest in G and/or metaphase. Flow cytometry of pheromone-synchronized cells confirmed that CKII is required in G, at a point which must lie at or beyond Start but prior to DNA synthesis. Similar analysis of hydroxyurea-synchronized cells indicated that CKII is not required for completion of previously initiated DNA replication but confirmed that the enzyme is again required for cell cycle progression in G and/or mitosis. These results establish a role for CKII in regulation and/or execution of the eukaryotic cell cycle.

Footnotes

↵* This was work was supported by National Institutes of Health Grant GM33237 and American Cancer Society Grant VM-19 (to C. V. C. G.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¹ The abbreviations used are:

CKII

casein kinase II

CDK

cyclin-dependent protein kinase

SMM

supplemented minimal medium

PBS

phosphate-buffered saline

5-FOA

5-fluoroorotic acid

DAPI

4′, 6′ -diamidino-2-phenylindole.
↵² D. E. Hanna and C. V. C. Glover, unpublished observation.
↵³ R. O. McCann, D. E. Hanna, and C. V. C. Glover, unpublished observations.
↵⁴ R. O. McCann and C. V. C. Glover, unpublished observations.
↵⁵ A. Rethinaswamy and C. V. C. Glover, unpublished observations.
- Received July 6, 1995.