Cookies on this website
We use cookies to ensure that we give you the best experience on our website. If you click 'Continue' we'll assume that you are happy to receive all cookies and you won't see this message again. Click 'Find out more' for information on how to change your cookie settings.

Unlike early embryonic cleavage divisions in certain animals, cell-cycle progression in yeast and probably also in all metazoan somatic cells requires the periodic transcriptional activation of certain key genes. Thus far, the only clear examples are genes that encode a class of unstable 'cyclin' proteins, which bind and activate the cdc2/Cdc28 protein kinase: the G1-specific cyclins encoded by CLN1 and CLN2, a B-type cyclin implicated in DNA replication encoded by CLB5; and four B-type cyclins involved in mitosis encoded by CLB1, 2, 3, 4. CLN1, CLN2, and CLB5 are transcribed in late G1, as cells undergo Start. A transcription factor composed of Swi4 and Swi6 proteins (called SBF) activates CLN1 and CLN2 transcription via a positive feedback loop in which Cln proteins activate their own transcription. A different but related transcription factor called MBF seems responsible for the late G1-specific transcription of most DNA replication genes including CLB5. We have purified MBF and shown that it contains Swi6 and a 110-120 kDa protein distinct from Swi4 (p120) that contacts DNA. Thus, we propose that SBF and MBF share a common regulatory subunit (Swi6) but recognize their promoter elements via distinct DNA binding subunits.

Original publication

DOI

10.1098/rstb.1993.0078

Type

Journal article

Journal

Philos Trans R Soc Lond B Biol Sci

Publication Date

29/06/1993

Volume

340

Pages

351 - 360

Keywords

Base Sequence, CDC28 Protein Kinase, S cerevisiae, Cell Cycle, Cyclins, DNA Replication, Feedback, Fungal Proteins, Genes, Fungal, Molecular Sequence Data, Molecular Weight, Oligonucleotide Probes, Promoter Regions, Genetic, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Transcription Factors