Although studies on unicellular yeast species have yielded considerable information on regulation of the cell cycle, multicellular organisms depend on additional regulatory mechanisms to determine the size of individual organs and the overall size of the organism. Björklund et al. combined RNA interference with flow cytometry to identify genes involved in regulating cell size, cytokinesis, cell death (or apoptosis or both), and progression through the cell cycle in Drosophila S2 cells. In addition to genes classically associated with cell cycle progression, unsupervised hierarchical clustering of genes associated with particular phenotypes implicated various other genes in regulation of the cell cycle, including genes associated with COP9 signalosome activity and with the Wnt, p38βMAPK, FRAP/TOR, and JAK/STAT signaling pathways. The authors conclude that their data will enable a systems biology analysis of cell cycle regulation in metazoans.
M. Björklund, M. Taipale, M. Varjosalo, J. Saharinen, J. Lahdenperä, J. Taipale, Identification of pathways regulating cell size and cell-cycle progression by RNAi. Nature 439, 1009-1013 (2006). [PubMed]