Figure 2
Common gene expression responses to CR in the laboratory mouse. Common gene expression responses to CR are ranked according to the number of tissue types in which genes were (A) significantly up regulated by CR or (B) significantly down regulated by CR. Additional File 5 provides a more comprehensive list of genes significantly regulated by CR across tissues, with genes ranked by p-values generated from Fisher's method. Genes shown in part (C) were not identified as common responses to CR, but have previously been associated with the mammalian CR response. Symbols shown within the grid reflect results of differential expression analyses for individual genes and tissues, given a comparison-wise type I error rate of 0.05 (i.e., no p-value adjustment for multiple testing of hypotheses). Filled circles indicate that a gene was significantly up regulated by CR (red circle) (P u < 0.05) or significantly down regulated by CR (green circle) (P d < 0.05) within a given tissue. The dash symbol is used to indicate cases in which the effects of CR are non-significant, although colored dash symbols indicate that expression is marginally increased by CR (red dash) (0.05 < P u < 0.10), or marginally decreased by CR (green dash) (0.05 < P d < 0.10). The asterisk symbol (✴) is used to designate instances where CR has significant effects, but there exists conflict among datasets. This may arise if at least two experiments exist, with at least one showing significant up regulation by CR (P u < 0.05), and at least one demonstrating significant down regulation by CR (P d < 0.05). Additionally, the asterisk is used when p-values, generated by combining results across experiments (Fisher's method), yield conflicting results in terms of whether a gene is up or down regulated (i.e., both P u < 0.05 and P d < 0.05). Asterisk symbols are colored red if there is stronger evidence that the gene is up regulated by CR (i.e., P u < 0.05 and P u < P d ), and are colored green if there is stronger evidence that the gene is down regulated by CR (i.e., P d < 0.05 and P d < P u ). The multiplication symbol (×) is used for cases in which no information was available regarding the effects of CR within a given tissue.