PubMed Health⌕ Search

Biomedical subjects

Hui Z Sheng

Publications and source records attributed to Hui Z Sheng.

6 recordsLinked to original sources
PubMed2006

Rabbit embryonic stem cell lines derived from fertilized, parthenogenetic or somatic cell nuclear transfer embryos.

Embryonic stem cells were isolated from rabbit blastocysts derived from fertilization (conventional rbES cells), parthenogenesis (pES cells) and nuclear transfer (ntES cells), and propagated in a serum-free culture system. Rabbit ES (rbES) cells proliferated for a prolonged time in an undifferentiated state and maintained a normal karyotype. These cells grew in a monolayer with a high nuclear/cytoplasm ratio and contained a high level of alkaline phosphate activity. In addition, rbES cells expressed the pluripotent marker Oct-4, as well as EBAF2, FGF4, TDGF1, but not antigens recognized by antibodies against SSEA-1, SSEA-3, SSEA-4, TRA-1-10 and TRA-1-81. All 3 types of ES cells formed embryoid bodies and generated teratoma that contained tissue types of all three germ layers. rbES cells exhibited a high cloning efficiency, were genetically modified readily and were used as nuclear donors to generate a viable rabbit through somatic cell nuclear transfer. In combination with genetic engineering, the ES cell technology should facilitate the creation of new rabbit lines.

Animals↗
PubMed2006

Regulated expression of TAF1 in 1-cell mouse embryos.

TATA binding protein (TBP) associated factor 1 (TAF1) is a member of the general transcription machinery. Interference in the function of TAF1 causes a broad transcriptional defect in early development. To explore possible roles of TAF1 in embryonic transcriptional silence and zygotic genome activation, we examined the expression of TAF1 in 1-cell mouse embryos. Using an immunofluorescence assay, TAF1 was not detected in embryos in the first few hours after fertilization. TAF1 appeared in pronuclei 6 h post-fertilization and reached a relatively high level before zygotic genome activation. These data show that besides TBP, another critical member of the general transcription machinery such as TAF1 is also absent or at an extremely low level at the outset of development. Combined deficiency in critical members of the general transcription machinery may account for embryonic transcriptional silence.

Animals↗
PubMed2006

Rabbits generated from fibroblasts through nuclear transfer.

Somatic cell nuclear transfer offers new opportunities for genetic engineering and genome preservation in mammalian animal species. We show that, in addition to cumulus cells, cultured adult rabbit fibroblasts are also capable of supporting full-term development after nuclear transfer. Nuclear transfer embryos constructed using serum-starved fibroblasts showed a significantly higher developmental rate than non-starved fibroblasts through preimplantation stages. A total of 467 nuclear transfer embryos were transferred into the oviducts of pseudo pregnant mothers. Eight of the 20 surrogate rabbits carried the pregnancy to term and five of them gave birth naturally to a total of nine rabbits. However, all of the offspring died before postnatal day 10. A Caesarean section was performed on three surrogates, giving birth to a total of five rabbits, three of them survived and grew into healthy adults. DNA analyses confirmed that these rabbits were genetically identical to the donor male rabbit. The present study demonstrates that rabbits can be cloned from adult fibroblasts after culture.

Animals↗
PubMed2005

Derivation and growing human embryonic stem cells on feeders derived from themselves.

Human embryonic stem cells (hESCs) are pluripotent. They have the potential to differentiate into every cell type of an organism. Since many human somatic cell types have the ability to support the growth of hESCs, cells differentiated from hESCs may also be able to support the growth of themselves. We tested this hypothesis by growing hESCs on feeders derived from themselves and demonstrated that such feeders did constitute an environment suitable for the derivation and long-term growth of hESCs. hESCs maintained in this system expressed all the markers indicative of the undifferentiated state and gave rise to cell types representative of all three primary germ layers upon differentiation. By modifying the genome of hESCs, feeders with special features can be derived and mass produced. The system will facilitate large-scale production of hESCs in a standardized animal pathogen-free environment.

Animals↗