Proteomic Analysis in the Cloned Porcine Extraembryonic Tissue.

Abstract

Although cloned animals have been successfully produced, a very low birth rate by SCNT embryos has been observed. Such low efficiency of cloning could possibly arise from abnormal or poorly developed placenta. In the present study, we present differentially regulated proteins in the extra embryonic tissue from SCNT embryos to understand the molecular nature of the tissue. Proteins expressed specifically or prominently on day 35 were identified in cloned porcine extraembryonic tissue using two-dimensional polyacrylamide gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF). The extraembryonic tissues were obtained from the recipients pregnant by natural mating (control) or SCNT embryos, respectively. The size and morphology of the samples looked similar in both groups. In the proteomic analysis, 33 proteins were identified as differentially regulated proteins in the SCNT extraembryonic tissue. Among these proteins, 30 were down-regulated, whereas the other 3 proteins were up-regulated. In the down-regulated proteins, cytokeratin 19 and vimentin were considered to be involved in regulation of early-implantation development and peroxiredoxin-2 and thioredoxin-like1 which is antioxidant enzyme reduce oxidative stress by scavenging reactive oxygen species (ROS). Among the up-regulated proteins, Hsp27, an apoptotic regulator that interacts with the key components of apoptotic signaling, was identified. These findings demonstrate that the extraembryonic embryonic tissue from SCNT embryos showed aberrant protein expression patterns during early pregnancy, although the morphology of the tissues looked normal and it can be suggested that the abnormal function of extraembryonic tissue in clone might be related negatively to placental formation and fetal development.