SET Domain Protein Regulates S. pombe Cytokinesis Figure 9. set3D mutants are impaired in their ability to modulate the expression of CESR genes in response to LatA treatment. Volcano plot (left panels) and scatter plot (right panels) analysis of the expression of CESR genes in wild-type (A) or set3D (B) strains in response to LatA treatment. Horizontal green lines in volcano plots represent a p-value of 0.05. Vertical green lines in volcano plots represent threshold for a 1.5 fold change in expression. Red squares in volcano plots indicate differentially expressed genes. Diagonal green lines in scatter plots represent the threshold for a 1.5 fold change in expression. The color of the squares in scatter plots indicates the level of expression of that gene in DMSO treated wild-type (A) or set3D (B) cells. Genes differentially expressed upon LatA treatment in wild-type cells are shown as green squares in scatter plots. doi:10.1371/journal.pone.0031224.g009 NCOR2, and TBL1X have themselves been shown to play a role in cytokinesis in human cells. In their study, Kittler et al. (2007) conducted a genome-wide RNAi screen aimed at identifying genes with roles in cell division in cultured HeLa cells. They discovered that the knockdown of MLL5, TBL1X, or NCOR2 resulted in defects in furrow ingression, cytokinesis failure, and finally the generation of tetraploid intermediates with twice the normal number of centrosomes. While highly speculative it is of interest to note that MLL5 is found in a region of chromosome seven that is frequently deleted in myeloid malignancies, and furthermore that decreased MLL5 expression levels correlate with unfavourable outcomes in patients with acute myeloid leukemia [36,37]. Moreover, the down- regulation of the NCOR2 gene can induce transformation in certain immortalized cell lines [38]. While a direct role in tumour progression via cytokinesis failure has not been shown, it is PLoS ONE | www.plosone.org 11 February 2012 | Volume 7 | Issue 2 | e31224