The Saccharomyces cerevisiae Start-Specific Transcription Factor Swi4 Interacts through the Ankyrin Repeats with the Mitotic Clb2/Cdc28 Kinase and through Its Conserved Carboxy Terminus with Swi6
Open Access
- 1 June 1996
- journal article
- Published by Taylor & Francis in Molecular and Cellular Biology
- Vol. 16 (6) , 2647-2655
- https://doi.org/10.1128/mcb.16.6.2647
Abstract
At a point in late G1 termed Start, yeast cells enter S phase, duplicate their spindle pole bodies, and form buds. These events require activation of Cdc28 kinase by G1 cyclins. Swi4 associates with Swi6 to form the SCB-binding factor complex which activates G1 cyclin genes CLN1 and CLN2 in late G1. In G2 and M phases, the transcriptional activity of SCB-binding factor is repressed by the mitotic Clb2/Cdc28 kinase. Mbp1, a transcription factor related to Swi4, forms the MCB-binding factor complex with Swi6, which activates DNA synthesis genes and S-phase cyclin genes CLB5 and CLB6 in late G1. Clb2/Cdc28 kinase is not required for the repression of MCB-binding factor transcriptional activity in G2 and M phase. We show here that the Swi4 carboxy terminus is sufficient for interaction with Swi6 in vitro. A carboxy-terminal domain of Swi6 is required and sufficient for interaction with Swi4. The carboxy terminus of Mbp1 is sufficient for interaction with Swi6, and the carboxy terminus of Swi6 is required for interaction with Mbp1. By coimmunoprecipitation, we show that Swi4 but not Mbp1 interacts with Clb2/Cdc28 kinase in vivo during the G2 and M phases of the cell cycle. We demonstrate that the ankyrin repeats of Swi4 mediate the interaction with Clb2/Cdc28 kinase. The ankyrin repeats constitute a domain by which a cell cycle-specific transcription factor can interact with cyclin-dependent kinase complexes, thus enabling it to link its transcriptional activity to cell cycle progression.Keywords
This publication has 64 references indexed in Scilit:
- Switching transcription on and off during the yeast cell cycle: Cln/Cdc28 kinases activate bound transcription factor SBF (Swi4/Swi6) at start, whereas Clb/Cdc28 kinases displace it from the promoter in G2.Genes & Development, 1996
- A new regulatory motif in cell-cycle control causing specific inhibition of cyclin D/CDK4Nature, 1993
- The fission yeast cdc18+ gene product couples S phase to START and mitosisCell, 1993
- Characterization of four B-type cyclin genes of the budding yeast Saccharomyces cerevisiae.Molecular Biology of the Cell, 1992
- A central role for SWI6 in modulating cell cycle Start-specific transcription in yeastNature, 1992
- Control of DNA synthesis genes in fission yeast by the cell-cycle gene cdclO+Nature, 1992
- Changes in a SWI4,6-DNA-binding complex occur at the time of HO gene activation in yeast.Genes & Development, 1991
- Transcriptional activation of CLN1, CLN2, and a putative new G1 cyclin (HCS26) by SWI4, a positive regulator of G1-specific transcriptionCell, 1991
- Single-step purification of polypeptides expressed in Escherichia coli as fusions with glutathione S-transferaseGene, 1988
- A repetitive DNA sequence that confers cell-cycle START (CDC28)-dependent transcription of the HO gene in yeastCell, 1985