Proteomic Investigation on Longissimus Muscle during Pre- and Postnatal Development Stages Between Landrace and Lantang Pigs Using 2D-DIGE

Mammalian myogenesis is a prenatal process of mono-nucleated myoblasts, fusing into multi-nucleated myotubes and then myofibers. To understand the regulatory mechanisms leading to distinct muscle characteristics, 2D-DIGE proteomic analysis were undertaken to compare longissimus dorsi muscle across 6 ontogenetic stages from 35 days post coitus (dpc) to 2 days post natal (dpn) between two pig breeds differing in muscle characteristics, Landrace (LR) and Lantang (LT). From more than 1500 protein spots detected on each 2D-DIGE gel, we identified 124 proteins. These proteins were involved in the biological processes including muscle structure, cell proliferation and differentiation, etc. Moreover, most of these proteins presented similar expression profile in both breeds during stages with the number of up-regulated proteins greater in early embryos and newborn piglets. Of note, more significantly up-regulated proteins were found in prenatal LR than that in LT, except for 91 dpc. Conversely, more significantly down-regulated proteins were found in LT, except for 77 dpc. These findings suggested that myogenesis started earlier but progressed more slowly in LT than in LR, in line with morphological observation that fewer primary myofibers were first found in LT at 35 dpc, while more primary myofibers were first found in LR at 49 dpc. Totally 51 muscle differentiation associated DEPs between breeds at same stages were found. Through STRING analysis, we deduced that these breed-related DEPs (ATP5A, ENO3, TPM3, etc.) might be involved in regulating the differential timing of myogenesis. These findings provide comprehensive characterization of porcine myogenesis.