The Function of microRNA-204 in Embryonic Stem Cells and Multiple inter-kingdom horizontal gene transfer in the evolution of phosphoenolpyruvate carboxylase gene family
MicroRNA is a small molecular non-coding RNA existed in many plant and animal genomes. It functions mainly by inhibiting the translation or degradation of mRNAs through binding to its target site in the 3'UTR region of the target gene mRNAs, thus plays an important role in post-transcriptional regulation. miRNA is proved to play an important role in self-renew and differentiation of embryonic stem cells. However, whether it also plays a role during the differentiation of embryonic stem cells towards neuronal cell has not been investigated. In this thesis, by applying the microarray and quantitative real-time PCR techniques, we demonstrated for the first time that a microRNA (miRNA-204) plays an important role in differentiation of macaque's embryonic stem cells towards neuronal cells. We further discovered by in vitro assay that miRNA-204 probably functions via regulating the target gene TGFBR2 and NR4A2. In addition, we constructed lentivirous vector to over-express miRNA-204 and successfully infected human embryonic stem cells with infection rate over 30%. This provides an important resource to further investigate the function of miRNA-204 in differentiation of human embryonic stem cell. In addition, we also discovered lots of inter-kingdom horizontal gene transfers in the evolution of phosphate enolpyruvate carboxylase gene family. Further analysis of the phylogeny of this gene family supported our discovery and also corrected the previous view that bacterial type PEPC originated from plant PEPC. This finding indicates that horizontal gene transfer plays an important role in evolution, and a network rather than a tree may better represent the relationship of species in evolution.
修改评论