Transcriptome analysis of discus fish (Symphysodon haraldi) skin and
brain to identify genes involved in ‘milk’ secretion during parental
care
Abstract
The discus fish Symphysodon spp., an Amazonian cichlid, employs an
unusual parental care behavior where free-swimming fry feed on parental
epidermal mucus after hatching. However, little is known about the
mechanism by which discus secrete ‘milk’ and the genes involved. In
order to study the unique behavior of discus fry feeding on parental
skin mucus on the molecular level, transcriptome sequencing was
performed on the skin and brain of female discus. Through the analysis
of skin transcriptome sequencing data, 228 differentially expressed
genes were obtained by comparing parental with non-parental fish,
including 126 up-regulated genes and 102 down-regulated genes. For the
brain, 86 differentially expressed genes were obtained including 71
up-regulated genes and 15 down-regulated genes. Through the analysis of
pathway in the skin, 7 metabolic pathways were obtained: arachidonic
acid metabolism pathway, adhesion pathway, apoptosis, steroid
biosynthesis, tuberculosis, P53 signaling pathway, serotonergic synapse,
which were related to 10 differentially expressed genes: JUNB, MRC,
DPP3, CASP3, PPID, ITGA11, ALOXE3, HBE, PTPRJ, GALE. Meanwhile, the
analysis of pathway in the brain, 20 metabolic pathways were obtained
e.g., estrogen signaling pathways, inflammatory medlator regulation of
TRP channels, non-small cell lung cancer, vascular smooth muscle
contraction, which were related to 9 differentially expressed genes:
PRKCD, H1-5, EDNRB, LAPTM, FOXB, OTX2, NRIF2, SOX1 and HBE.