Identifying Muscle Growth-Related Genes of Mandarin Fish (Siniperca chuatsi) by Transcriptome, and Exploring the Expression in Different Sizes and Compensatory Growth

Abstract BackgroundHow organisms display many different biochemical, physiological processes through genes expression and regulatory mechanisms affecting muscle growth is a central issue in growth and development. In Siniperca chuatsi, the growth-related genes and underlying relevant mechanisms are poorly understood, especially for difference of body sizes and compensatory growth performance. ResultsThe muscle from different sizes of individuals was subjected to transcriptome analysis by RNA-sequencing. Results showed that 8,942 different expression genes (DEGs) were identified after calculating the RPKM. The DEGs involved in GH-IGF pathways, protein synthesis, ribosome synthesis and energy metabolisms, which were expressed at higher level in small individuals (S), whereas in the large fish (L) little expression was found. In repletion feeding and compensatory growth experiments, 8 more significant DEGs were used for further research (GHR2, IGFR1, 4ebp, Mhc, Mlc, Myf6, MyoD, troponin), and this research revealed different temporal and spatial expression patterns of these genes. When food was plentiful, 8 genes participated in and promoted the growth and muscle synthesis, respectively. Starvation can be shown to inhibit the expression of Mhc, Mlc and troponin, and high expression of GHR2, IGFR1 and 4ebp inhibited growth. MyoD can sense and regulate the hunger and work with Mhc and Mlc to accelerate the compensatory growth of S.chuatsi. ConclusionsThis study is helpful to understand the regulation mechanisms of muscle growth-related genes. The elected genes will contribute to the selective breeding in future as candidate genes.