Transcriptomic analysis reveals abundant differential gene expression and alternative splicing events in the heart tissues of the Nile tilapia in response to acute hypoxia. Oreochromis niloticus

Using RNA-seq, we surveyed the differential expressed genes (DEG) and identified genes that undergo differential usage of exons and splice junctions events (DUES) in the heart of a hypoxia tolerant fish, Nile tilapia, Oreochromis niloticus following 12h hypoxia treatment. We detected 289 DEG and 89 DUES hypoxia responsive genes in the heart tissues. Functional analysis significantly associated these genes with the categories related to energy conservation, protein synthesis and immune response. Interestingly, we found different enrichment categories (GO, pathway and protein class) within and between the DEG and DUES categories. For example, the Isomerase activity (5.97 fold; P = 0.036), Oxidoreductase activity (3.08 fold; P = 0.00516) and Glycolysis (19.54 fold; P = 0.00926), Oxidative stress process (12.1 fold; P = 0.00195) were significantly enriched for the DEG gene dataset, but the Structural constituent of ribosome (16.02 fold; P = 1.06E-06) and Structural molecule activity (5.08 fold; P = 4.87E-06), Ribosomal protein (16.19 fold; P = 1.5E-07) and RNA binding protein (5.5 fold; P = 4.36E-05) were significantly enriched only for the DUES genes.