Regulatory Roles of Peroxisomal Metabolic Pathways Involved in Musk Secretion in Muskrats

Abstract

In this study, we analyzed the main components of muskrat musk by gas chromatography–mass spectrometry, the results showed that muskrat musk contained fatty acids (29.32%), esters (31.89%), cholesterol (4.38%), cyclic ketones (16.31%), alcohols (6.42%) and other compounds, among which 9-octadecenoic acid accounted for 4.89%. We also analyzed the genes of the metabolic pathway in the scent gland at the transcriptomic level during musk-secreting and non-secreting seasons by RNA-seq (RNA sequencing). We detected 21 genes in the peroxisomal metabolic pathways, including PEX14(peroxin-14) and ACOX3(acyl-CoA oxidase), which exhibited significant differential expression between the musk-secreting season and the non-secreting season (p < 0.05). The RNA-seq results for these genes were validated by reverse transcription PCR(RT-PCR) for both seasons. In addition, we examined changes in the composition of muskrat musk from the glandular cells of scent glands cultured in vitro after RNA interference-mediated silencing of 2 differentially expressed genes, ACOX3 and HSD17B4(D-bifunctional protein, DBP). The 9-Octadecenoic acid content in muskrat musk decreased significantly following the silencing of ACOX3 and HSD17B4(D-bifunctional protein, DBP). These results suggest that peroxisomal metabolic pathways play important roles in the regulation of musk secretion in scent glands in the muskrat.