Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

In budding yeast genes that encode G1 cyclins and proteins involved in DNA synthesis are transcriptionally activated in late G1. A transcription factor, called SBF, is composed of Swi4 and Swi6 proteins and activates transcription of G1 cyclin genes. A different, but related, complex called MBF binds to MCB elements (Mlu I cell cycle box) found in the promoter of most DNA synthesis genes. MBF contains Swi6 and a 120-kilodalton protein (p120). MBF was purified and the gene encoding p120 (termed MBP1) was cloned. A deletion of MBP1 was not lethal but led to deregulated expression of DNA synthesis genes, indicating a direct regulatory role for MBF in MCB-driven transcription. Mbp1 is related to Swi4. Strains deleted for both MBP1 and SWI4 were inviable, demonstrating that transcriptional activation by MBF and SBF has an important role in the transition from G1 to S phase.


Journal article



Publication Date





1551 - 1557


Amino Acid Sequence, Base Sequence, CDC28 Protein Kinase, S cerevisiae, Cloning, Molecular, Cyclins, DNA, Fungal, DNA-Binding Proteins, Fungal Proteins, G1 Phase, Gene Expression Regulation, Fungal, Genes, Fungal, Molecular Sequence Data, Mutation, Promoter Regions, Genetic, S Phase, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Sequence Alignment, Transcription Factors