The regulatory network around these cyclins, particularly in G1, has been interpreted as a size control network in budding yeast , and cell size as being decisive for the START transition.

Cell sizes emerge in the model, which predicts that a single CDK-cyclin pair per growth phase suffices for size control in budding yeast , despite the necessity of the cell cycle network around the cyclins to integrate other cues.

Recent evidence strongly suggests that also in budding yeast size control is likely to be exerted outside of G1 [9, 10].

The fission yeast Schizosaccharomyces pombe has a size control checkpoint at the G2/M boundary and many of its components are conserved in budding yeast [11, 12].

The observation that the budded phase duration responds to growth media and the high degree of conservation between the two yeasts prompts the question, whether a size control mechanism guards mitotic entry in budding yeast as well [13—16].

Budding yeast grows and divides asymmetrically and, therefore, growth of the mother and the bud is considered separately [39].

Using a simplified budding yeast cell cycle model perturbed by intrinsic noise, we systematically explore these issues from an energy landscape point of view by constructing an energy landscape for the considered system based on large deviation theory.

We performed a careful study of the budding yeast cell cycle process from an energy-landscape point of view.

The energy landscape of the budding yeast cell cycle is mainly comprised of two parts on a global scale: a deep pit that holds a cell in its G1 state when the environment is not suitable for division, and one unidirectional flat canal that performs a robust and accurate cell cycle progress once the system is excited (as summarized in Fig.

Even with such limitations, we believe our meticulous study of the energy landscape of the simplified budding yeast cell cycle model is of general interest to those studying other complicated cell cycle dynamics.

Using the described method, we constructed the energy landscape S(x) for a budding yeast cell cycle network.

Using a simplified budding yeast cell cycle model driven by intrinsic noise, we systematically explore the above issues from an energy landscape point of view by constructing a global quasi-potential energy landscape for the budding yeast cell cycle model.

Overall, our energy landscape study shows that the budding yeast cell cycle is a robust, adaptive and multistage dynamical process.

We first assume that the DNA replication triggers the mitosis as a “domino” mechanism in the budding yeast cell cycle.

Based on the key regulatory network [17] and our previous study on budding yeast [22] , the cell cycle regulatory network can be simplified and separated into G1 /S, early M and late M modules, as shown in Fig.

The three-node Budding Yeast Cell Cycle Model, 11.

The regulatory network of cell-cycle process in budding yeast .

Our in silico analysis carried out genome-wide via the StabFIex algorithm, shows the conserved presence of highly flexible regions in budding yeast genome as well as in genomes of other Saccharomyces sensu stricto species.

Here, we study DNA flexibility in budding yeast chromosomes.

In budding yeast , the ability of genes to respond to environmental changes has been related to nucleosome occupancy in 5’ ends and 3’ - ends [42, 43].

In this paper we approach the problem of biological meaning of DNA helix flexibility by analysing budding yeast chromosome sequences.