Figure 3

    This figure displays the degree of differential alternative splicing of genes in PAH and PHH models using data from acquired through RNA-seq, and verifies these findings through RT-PCT.

    Part A mirrors figure 2B in construction, but for eight genes (some of which are from the set of 33 shown in table 1) known to be alternatively spliced in PAH and PHH models. The red asterisks indicate the positions of the particular exons (blue boxes on blue lines under each histogram) that are alternatively spliced in hypertrophy models. The y axes in panels of A correspond to numbers of reads of segments acquired from RNA-seq, which are used as the raw data for the histograms in part B.

    Bar clusters in the histograms of part B correspond to gene isoforms shown under adjacent graphs in part A. Individual bars show the expression level for each of these gene isoforms as labeled. Error bars indicate standard error. This series of graphs reveals a range of expression levels for certain splice variants between PAH and PHH (TAC vs. exercise for Egf17-1) and between TAC and sham groups.

    Part C shows the results of reverse transcriptase polymerase chain reaction (RT-PCR) amplifying the cDNA corresponding to certain transcript regions to verify AS. This procedure confirmed the proposed AS for these genes in PAH and PHH models by confirming the presence of key exons in these splice variants. Density of bands in C correlates generally with degree of expression in B for given isoforms containing the exons listed to the right of blots in C (Rcan1 provides a clear example of this).

    Overall this figure shows confirmation of the differential alternative splicing – featuring both inclusion and exclusions of exons – of genes between PAH and PHH models, and validifies RNA-seq as a  tool for visualizing this data. This figure's data corroborates with data in table 1 and suggests possible changes in domain presence, activity and localization of different specific gene products between PAH and PHH models, even when gene expression in general may be similar. In order to facilitate a qualitative, intuitive understanding of data form this and previous figures, however, some larger patterns relating to these genes functions must be clarified as well; this is introduced in figure 4.

References 

Song, H. K., Hong, S. E., Kim, T., Kim D. H., et al. (2012). Deep RNA sequencing reveals novel cardiac transcriptomic signatures for physiological and pathological hypertrophy. PLoS One, 7, e35552.

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