Differential analysis of microRNAs in zebrafish gills under hypoxic stress

In order to study the biological function of microRNAs (miRNAs) in response to hypoxic stress, we perfomed high-throughput miRNAs sequencing in the gill tissues of zebrafish (Danio rerio) under hypoxic stress and normoxic condition, and analyzed the differences in miRNAs expression in the gill tissues of zebrafish. The results show that a total of 15 miRNAs are significantly differentially expressed in the gills of zebrafish under hypoxic stress and normoxic condition, among which 13 miRNAs were up-regulated significantly and 2 miRNAs were down-regulated significantly. Moreover, we performed a correlation analysis on miRNAs sequencing and zebrafish gill transcriptome, and predicted the target genes for 28 heat shock protein genes that were significantly differentially expressed under hypoxic stress and normoxic condition screened in the previous stage. The result shows that miR-455-3p, which was expressed significantly low under hypoxic stress, targeted to increase the expression of hspa14 and dnajb6b and enhance the adaptability to hypoxic stress. In addition, miR-194a and miR-155, which were highly expressed under hypoxic stress, targeted five heat shock protein genes (hspa12a, dnajc5aa, hspb7, hsp70.3, dnajb2) and four heat shock protein genes (hspa12a, hspg2, hspa13, dnajb2) to regulate zebrafish's adaptation to hypoxic condition.