Transcriptional Regulation in the G1-S Cell Cycle Stage in Fungi: Insights through Computational Analysis

Viktor Martyanov1, Robert H. Gross2, *
1 Department of Genetics, Dartmouth Medical School, Hanover, NH 03755, USA
2 Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA

© 2012 Martyanov and Gross

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA; Tel: 603-646-2059; Fax: 603-646-1347; E-mail:


The transcription factor complexes Mlu1-box binding factor (MBF) and Swi4/6 cell cycle box binding factor (SBF) regulate the cell cycle in Saccharomyces cerevisiae. They activate hundreds of genes and are responsible for nor-mal cell cycle progression from G1 to S phase. We investigated the conservation of MBF and SBF binding sites during fungal evolution. Orthologs of S. cerevisiae targets of these transcription factors were identified in 37 fungal species and their upstream regions were analyzed for putative transcription factor binding sites. Both groups displayed enrichment in specific putative regulatory DNA sequences in their upstream regions and showed different preferred upstream motif loca-tions, variable patterns of evolutionary conservation of the motifs and enrichment in unique biological functions for the regulated genes. The results indicate that despite high sequence similarity of upstream DNA motifs putatively associated with G1-S transcriptional regulation by MBF and SBF transcription factors, there are important upstream sequence feature differences that may help differentiate the two seemingly similar regulatory modes. The incorporation of upstream motif sequence comparison, positional distribution and evolutionary variability of the motif can complement functional infor-mation about roles of the respective gene products and help elucidate transcriptional regulatory pathways and functions.

Keywords: G1-S transition, cell-cycle, fungal evolution, motif finding, transcriptional regulation, regulons, TFBS, gene regulation.