Production of artificial synthetic spidroin gene 4S-transgenic cloned sheep embryos using somatic cell nuclear transfer.

Spider silk, which has remarkable characteristics, has wide application prospects in many fields. Many researchers have explored potential methods for directly producing spider silk proteins and spidroins with mechanical properties or obtaining recombinant spider silk fibers by genetic engineering methods. However, there are still some shortcomings with these methods, such as inability to simulate the fibrosis process of spider silk.

Endo-siRNA deficiency results in oocyte maturation failure and apoptosis in porcine oocytes.

Both microRNAs (miRNAs) and endogenous small interfering RNAs (endo-siRNAs) play key regulatory roles in gene expression. Some studies have demonstrated that the function of miRNA is suppressed in mouse oocytes, suggesting that endo-siRNA, not miRNA, is essential for female meiosis. This finding has yet to be confirmed in other species.

Discovery of porcine maternal factors related to nuclear reprogramming and early embryo development by proteomic analysis.

Background: Differentiated cell nuclei can be reprogrammed to a pluripotent state in several ways, including incubation with oocyte extracts, transfer into enucleated oocytes, and induced pluripotent stem cell technology. Nuclear transfer-mediated reprogramming has been proven to be the most efficient method. Maternal factors stored in oocytes have critical roles on nuclear reprogramming and early embryo development, but remain elusive.

[Mammalian DNA methylation and its roles during the induced re-programming of somatic cells].

The technology of induced pluripotent stem cell (iPS) provides the possibility to reverse the terminal differentiated cells to pluripotent stem cells, and is therefore of great importance in both the theoretical research of stem cells and regenerative medicine. However, the efficiency of current induced reprogramming methods is extremely low, and the incomplete reprogramming often happens. It has been reported that some epigenetic memory of the somatic cells exists in these incomplete reprogrammed iPS cells, and DNA methylation, as a relative long-term and stable epigenetic modification, is one of the important factors that influence the efficiency of reprogramming and differentiative capacity of iPS cells.

[Regulation of differentiation of mesenchymal stem cells by the Hippo pathway effectors TAZ/YAP].

Mesenchymal stem cells (MSCs) are pluripotent cells which can differentiate into several distinct lineages, such as chondrocytes, adipocytes and myofibers. It has been reported that the lineage-specific transcriptional factors including Runt related transcription factor 2 (RUNX2), Peroxisome proliferator-activator receptor gamma (PPARgamma) and Myogenic differentiation 1 (MyoD) may play key regulatory roles among the differentiation of MSCs. Recently, researches have confirmed that the Hippo pathway impacts the differentiation fates of MSCs through regulating the activity of line- age-specific transcription factors by the Hippo pathway effectors Tafazzin (TAZ) and/or Yes-associated protein (YAP).

[Role of microRNA in induced pluripotent stem cell].

MicroRNAs are ~22 nt long small noncoding RNA molecules that silence post-transcription gene expression. It has proven that microRNAs are widely expressed in eukaryotes and play an important role in the regulation of cell differentiation and development, growth metabolism, and many other cell activities. Induced pluripotent stem cells (iPS) are a type of pluripotent stem cells reprogrammed from somatic cells and exhibit the essential characteristics of embryonic stem cells.

The type and extent of injuries in vitrified mouse oocytes.

To improve the vitrification of mouse oocytes using straws, we attempted to estimate the type and extent of injuries during vitrification with a vitrification solution EAFS10/10. Injuries in oocytes were assessed based on cellular viability, the integrity of the plasma membrane, the status of the meiotic spindle/chromosomes, and morphological appearance. For morphologically normal oocytes, the ability to be fertilized and to develop into blastocysts was examined.

[Cell lineage tracing of regenerating cells after partial pancreatectomy using pseudo-type retrovirus].

Pancreas is an important mixed gland having both endocrine and exocrine functions, and has been proven regeneration after injury. To explore the cell lineage tracing methods in pancreas in vivo and the regenerate cells source, we used pseudo-type retrovirus to transfect adult mouse pancreas which had been partially pancreatectomized by rubbing the kerf using a cotton stick saturated with retrovirus suspension then injecting 100 microL retrovirus suspension into pancreas, injecting 100 microL retrovirus by caudal vein, or interperitoneally injecting retrovirus respectively. The results showed that the method of rubbing the kerf then injection of retrovirus suspension into pancreas could more effectively mark the pancreatic cells than the caudal vein injection and the intraperitoneal injection did in vivo.