Biomedical subjects

Xiao-Rong An

Publications and source records attributed to Xiao-Rong An.

6 recordsLinked to original sources

PubMed2006

Expression of basic fibroblast growth factor results in the decrease of myostatin mRNA in murine C2C12 myoblasts.

During the development and regeneration of skeletal muscle, many growth factors, such as basic fibroblast growth factor (bFGF, FGF-2) and myostatin, have been shown to play regulating roles. bFGF contributes to promote proliferation and to inhibit differentiation of skeletal muscle, whereas myostatin plays a series of contrasting roles. In order to elucidate whether the expression of bFGF has any relationship with the expression of myostatin in skeletal muscle cells, we constructed a eukaryotic expression vector for the expression of exogenous bFGF in murine C2C12 myoblasts. Quantitative RT-PCR assays indicated that with the increase of the expression of exogenous bFGF gene, the expression of endogenous myostatin gene was suppressed at mRNA level and protein level.

Animals↗

PubMed2006

[Transgenic mice produced by intracytoplasmic sperm injection].

In our previous study, normal and fertile mice were successful produced from oocytes following intracytoplasmic sperm injection (ICSI). In the present study, the possibility of producing transgenic embryos and offspring with this procedure was evaluated. After freezing-thawed once using HEPES-CZB medium without cryoprotectants, the cauda sperm from KM fertile male were exposed to the circular or linear pEGFP-N1 DNA for 1 min and then co-injected into metaphase II oocytes of B6D2F1 strain. When the zygotes with two pronuclei were cultured in CZB medium to day 3.5, 39.1% (9/23) of them, derived from oocytes co-injected with sperm head and pEGFP-N1 plasmid DNA, were expressed GFP protein. After transfer of the ICSI embryos with two pronuclei from co-injection of sperm head and foreign DNA, seven recipients delivered 30 pups (23.8%, 30/126). Southern blot results revealed that three of sixteen offspring integrated with GFP and neomycin genes together (18.8 %). Interestingly, all of them were produced from oocytes co-injected sperm head and linear DNA (33.3%, 3/9), while none of seven ICSI offspring integrated either GFP or neomycin gene in the group of co-injection of sperm head and circular plasmid DNA. These results indicated that the high efficiency of transgenic mouse could be produced by ICSI. It may be shown that linear DNA is more easily to integrate into host genome than circular DNA when ICSI was used to produce transgenic animals.

Animals↗

PubMed2005

Cloning and sequence analysis of myostatin promoter in sheep.

To better understand the structure and function of the myostatin's gene promoter region in sheep, we cloned and sequenced a 1.517 kb fragment containing the 5'-regulatory region of the sheep myostatin gene (GenBank accession number is AY918121). The promoter sequence consists of three TATA boxes, one CAAT box, and eight putative E-boxes. Some putative muscle growth response elements for Octamer-binding factor 1(Octamer), Activator protein 1(AP1), Growth factor independence 1 zinc finger protein (Gfi-1B), Myocyte enhancer factor 2 (MEF2), Muscle-specific Mt binding site (MTBF), Glucocorticoid response elements (GRE) and Progesterone receptor binding site (PRE) were detected. Some of the motifs are conserved as compared to with that in the goat, bovine and porcine myostatin promoters. However, some differences were also found.

Animals↗

PubMed2005

[Normal mice derived from oocytes following intracytoplasmic sperm injection (ICSI)].

This paper describes the use of piezo-driven micropipette for intracytoplasmic sperm injection of mice eggs. The head of fresh spermatozoa from KM (Kunming) fertile mice was individually injected into mature oocytes of hybrid mice B6D2F1. Approximately eighty three percent of sperm-injected oocytes survived, and 84.0% of them fertilized normally (extrusion of the second polar body and formation of male and female pronuclei). The eggs fertilized by sperm injection could develop in vitro to 2-cell (98% vs 94.7%), 4-cell (89.5% vs 92.1%) stages, no significantly (P > 0.05) different from embryos fertilized in vivo but there were significantly (P < 0.01) few morulae (63.8% vs 84.2%) and blastocysts (25.7% vs 68.4%) developed in vitro after further culture in vitro in the group of ICSI. When 120 embryos at the pronuclear stage were transferred to seven pseudopregnant KM female, 23.3% of the embryos (0 - 50%, depending on the host) reached the full term. Except for three that were cannibalized soon after birth, all of the young (25 pups) developed into normal and fertile adult. Here we report the first birth of mouse offspring following ICSI in China. These studies may increase understanding of the fertilization process and of how ICSI works.

Animals↗

PubMed2003

[Molecular cloning, expression mutation of myostatin and study on biochemical activity of its C-terminal peptide].

Myostatin, a member of the TGF-beta family, negatively regulates skeletal muscle development. Mutation of myostatin activity leads to increases muscle growth and carcass lean yield. The bovine myostatin mutation cDNA was amplified by polymerase chain reaction, and then sub-cloned into the expression vector pET-30a( + ) to form the expression plasmid pET30a (+)-action/ Myostatin. The recombinant plasmid was transformed into E. coli BL21. The overexpression product of pET30a (+)-action/ Myostatin was been showed in vitro. Sheep skeletal muscle cell were cultured with the purified myostatin mutation C-terminal peptide. The results of this study suggest that had a powerful activity to stimulate the hyperplasia and proliferation of sheep muscle cells and shows high biochemical activity.

Animals↗

PubMed2002

[Transgenic animals bioreactors].

The production of human recombinant proteins in milk of transgenic farm animals offers a safe, very cost-effective source of commercially important proteins that cannot be produced as efficiently in adequate quantities by other methods. This review has summarized the current status of gene selection, vector construct, transgenic methods, economics, and obvious potential in transgenic animals bioreactors. Recently, a more powerful approach was adopted in the transgenic animals founded on the application of nuclear transfer. As we will illustrate, this strategy presents a breakthrough in the overall efficiency of generating transgenic farm animals, product consistency, and time of product development. The successful adaptation of Cre-/lox P-mediated site-specific DNA recombination systems in farm animals will offer unprecedented possibilities for generating transgenic animals.

Animals↗