Figure 6

Correlation between miRNAs with predicted effects on mRNA expression and miRNA expression levels detected by miRNA microarrays. miRNAs were divided into those with significantly lower than expected target mRNA expression (labeled 'low'), those with no detectable effect on their target expression (labeled 'mid') and those with significantly high target expression (labeled 'high'). The boxplots show the expression values (y-axis), determined by Thomson et al. [33], of the miRNAs in each group (x-axis). The expression of miRNAs with low target gene expression is significantly higher (t-test, p < 0.05) than that of those with mid or high target expression (in all tissues except heart). Thomson et al. [33] labeled the microRNAs from each tissue with Cy3 and used a reference oligonucleotide set corresponding to all mature microRNAs, labeled with Cy5 (red channel) in all hybridizations. This reference set provided an internal hybridization control for every probe on the array. The miRNA microarray expression values used in our analyses are median centered normalized log ratio Cy3/Cy5 values.