Cyclin cell cycle regulation

Cell Cycle Control. Figure 1 Cell cycle regulation by Cyclin dependent kinases (CDKs). Different cyclins bound to different CDKs promote the transition from one cell cycle phase into another. CDK-dependent phosphorylation of Rb is required to release active E2F transcription factors, which promotes entry into S phase. 

Nasmyth MCM is not a cell cycle-regulated gene. If this were the case, then cyclins would be good markers, but they are lousy markers. 

FIG. 2. Schematic representation of the switch from a maternal to a zygotic programme taking place in Xenopus between the MBT and the onset of gastrulation. This switch has been shown to operate for cell cycle regulators such as cyclin E and MCM proteins. We propose that maternal regulator(s) of apoptosis such as X-IAP 1 are also expressed in this kind of pattern and could explain the apoptotic program we have uncovered. 

Cell Cycle Regulation by Cyclin-Dependent Kinases... 

Hengst, L., Dulic, V., Slingerland, J., Lees, E., and Reed, S. (1994). A cell cycle regulated inhibitor of cyclin-dependent kinases, Proc Natl Acad Sci USA 91, 5291-5295. 

The cyclosome (or APC) is a high molecular weight complex that degrades proteins containing a specific recognition sequence, the destruction box (see chapter 13.2.4). Substrates are cell cycle regulators as e.g. cyclins, kinase inhibitors and spindle-associated proteins. Importantly, some forms of the cyclosome require phosphorylation in order to be active (fig. 2.15B). It is still unclear which of the many subunits carries the E3 enzyme activity. 

These four control mechanisms modulate the activity of specific CDKs that, in turn, control whether a cell will divide, differentiate, become permanently quiescent, or begin a new cycle of division after a period of quiescence. The details of cell cycle regulation, such as the number of different cyclins and kinases and the... 

Sielecki, T.M., Boylan, J.F., Benfield, P.A., Trainor, G.L. Cyclin-dependent kinase inhibitors useful targets in cell cycle regulation. Journal of Medicinal Chemistry 2000, 43, 1-18. 

J. Zwicker, F. C. Lucibello, L. A. Wolfraim, C. Gross, M. Truss, K. Engeland, and R. Muller, Cell cycle regulation of the cyclin A, cdc25C and cdc2 genes is based on a common mechanism of transcriptional repression, EMBO J. 74 4514 (1995). 

Recently considerable attention has been focused on the metabolites belonging to bisindolylmaleimides such as staurosporine (28) [12], UCN-01 (29) [13], rebeccamycin (30) [14], which were produced by the family of Streptomyces, Actinomycetes, and Saccharothrixes. These metabolites cause topoisomerase I mediated DNA cleavage, potent inhibition of protein kinase C and cell-cycle-regulating cyclin-dependent kinase (CDK), and cell-cycle checkpoint inhibition [15]. It seems interesting that myxomycetes also contain the bisindole metabolites having related structures to 28 - 30. 

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