Index-tagged cDNA libraries were constructed from total RNA (1 μg) with the TruSeq RNA sample preparation v2 kit (Illumina). Four biological replicates consisting of three pooled hearts were used per sample. Quality, quantity, and size distribution of the Illumina libraries were determined using the DNA-1000 kit (Agilent Bioanalyzer). Libraries were sequenced (single-end mode and length of 75 bp) on the Genome Analyzer IIx system using the standard RNA sequencing protocol in the TruSeq SBS kit v5. Fastq files containing reads for each library were extracted and demultiplexed using Casava v1.8.2 pipeline.