PSXIII-11 Large-scale profiling of non-conventional peptides in several tissues of Yak (<i>Bos mutus</i>) by peptidogenomic pipeline

Abstract Wild Yak (Bos Mutus) has great research value in understanding ruminant animal physiology and biomedicine as a model of plateau hypoxia adaptation. Non-conventional peptides (NCPs), including small open reading frame-encoded peptides, have been found to have a key role in basic plant and animal biological processes. In this study, we first developed an integrated peptidogenomic pipeline, used high-throughput mass spectrometry to probe a customized six-frame translation database, combined genome, transcriptome and translatome analysis, and applied it to large-scale identification of NCPs in several important tissues related to metabolism, immunity, digestion and reproduction in yaks. Here we report that 9,550, 7,016, 7,958, 7,537, 7,921 and 13,973 NCPs were identified in liver, lung, spleen, muscle, testis and small intestine, respectively. These NCPs have distinct characteristics and differences from conventional peptides in which they are derived from introns, 3 ‘UTR, 5’ UTR, out-of-frame exons, and intergenic regions (IGRs). In addition, although NCPs were identified in a wide range and existed in various tissues of yaks, they also showed differences in tissue expression. Interestingly, we also found that the number of hydrophobic amino acids in NCPs was greater than that of hydrophilic amino acids in different tissues of yaks, but the result of CPs was opposite. These results indicate that they may be related to the maintaining protein stability and anti-oxidative stress. The physiological functions were further verified by the in vitro antioxidant activity of 20 candidate peptides, but the specific physiological mechanisms remain to be further investigated. In summary, our study developed an integrated peptidogenomic pipeline for the first time to extensively identify NCPs in wild yaks, indicating that a large portion of yak genome can be translated into molecules with biological functions, which is of great significance for functional genomic studies and provides a reference for the discovery of new functional genes for environmental adaptability of ruminant animals.