Regassa et al. BMC Genomics 2011, 12:57 http://www.biomedcentral.com/1471-2164/12/57 Page 11 of 20 Figure 12 Hierarchical clustering and heat map of some of the top differentially expressed genes between GVCCs (A) and MIICCs (B) with a fold change of more than 256. Abbreviations, GVCCs and MIICCs stand for germinal vesicle and metaphase II CCs respectively. Numbers (1, 2 and 3) indicate the three biological replicates that were used for microarray hybridization. growth and maturation have been widely addressed [2,60,61] we are not going to discuss them here. The c-mos proto-oncogene product MOS is believed to be an active component of the cytostatic factor that stabilizes and sustains the activity of maturation-promoting factor (MPF). Notable interspecies differences exist among different vertebrates regarding the physiological effects of MOS on oocyte maturation. Its higher expression in oocytes both at GV and MII stages in the current study supports previous claims that MOS is required both for the activation of MPF during meiosis I and II and for the meiotic arrest at meiotic MII [62,63]. Figure 13 The top significantly changed GO terms (biological processes) with the proportion of transcripts involved among these over expressed in GV and MIICCs relative to each other. The proportion of transcripts in a GO term was calculated as the number of genes over expressed in one sample divided by the total number of genes that are involved in that given GO term multiplied by 100 (P < 0.001). Figure 14 The top significantly changed GO terms (cellular and molecular functions) with the proportion of transcripts involved among these over expressed in GV and MII CCs relative to each other. The proportion of transcripts in a GO term was calculated as the number of genes over expressed in one sample divided by the total number of genes that are involved in that given GO term multiplied by 100 (P < 0.001).