Identification of pathways regulating cell size and cell-cycle progression by RNAi.
Many high-throughput loss-of-function analyses of the eukaryotic cell cycle have relied on the unicellular yeast species Saccharomyces cerevisiae and Schizosaccharomyces pombe. In multicellular organisms, however, additional control mechanisms regulate the cell cycle to specify the size of the organism and its constituent organs. To identify such genes, here we analysed the effect of the loss of function of 70% of Drosophila genes (including 90% of genes conserved in human) on cell-cycle progression of S2 cells using flow cytometry. To address redundancy, we also targeted genes involved in protein phosphorylation simultaneously with their homologues. We identify genes that control cell size, cytokinesis, cell death and/or apoptosis, and the G1 and G2/M phases of the cell cycle. Classification of the genes into pathways by unsupervised hierarchical clustering on the basis of these phenotypes shows that, in addition to classical regulatory mechanisms such as Myc/Max, Cyclin/Cdk and E2F, cell-cycle progression in S2 cells is controlled by vesicular and nuclear transport proteins, COP9 signalosome activity and four extracellular-signal-regulated pathways (Wnt, p38betaMAPK, FRAP/TOR and JAK/STAT). In addition, by simultaneously analysing several phenotypes, we identify a translational regulator, eIF-3p66, that specifically affects the Cyclin/Cdk pathway activity.
Molecular and Cancer Biology Program, Biomedicum Helsinki, PO Box 63 (Haartmaninkatu 8), FI-00014 University of Helsinki, Finland.
Mikael
M
Björklund
Minna
M
Taipale
Markku
M
Varjosalo
Juha
J
Saharinen
Juhani
J
Lahdenperä
Jussi
J
Taipale
D021581:Active Transport, Cell Nucleus; D000818:Animals; D002453:Cell Cycle / Q000235:genetics*; D002460:Cell Line; D048429:Cell Size; D017124:Conserved Sequence / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology* / Q000235:genetics* / Q000378:metabolism; D015723:Gene Library; D017344:Genes, Insect / Q000235:genetics; D006801:Humans; D010641:Phenotype; D010766:Phosphorylation; D034622:RNA Interference; D015398:Signal Transduction
D029721:Drosophila Proteins