Qualitative Analyses of Protein Phosphorylation in Bovine Pluripotent Stem Cells Generated from Embryonic Fibroblasts

Pluripotent stem cells (PSCs) generated from somatic cells via ectopic expression of specific transcription factors provide an unlimited cell resource for regenerative medicine and transgenic breeding. Here, we describe the successful generation of bovine induced PSCs (biPSCs) from foetal fibroblasts by lentivirus-mediated delivery of bovine pluripotency reprogramming factors (PRFs) OCT3/4, SOX2, KLF4, c-MYC, NANOG and LIN28. The generated biPSCs resembled embryonic stem cells (ESCs) in their gene expression profiles, self-renewal capabilities and proliferation, as well as maintenance of a normal karyotype and differentiation into diverse cell types of all three germ layers both in vitro and in vivo. Qualitative phosphoproteomics of biPSCs revealed a large number of phosphorylated proteins, which might be related to the control of biPSCs status. The successful generation of biPSCs and the analysis of their phosphoproteome would further our understanding of the epigenetic mechanisms underlying iPSC pluripotency, thus promoting their application in bovine transgenic breeding and marking avenues for future research.