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At least 991 records · Page 55Linked to original sources
PubMed1998

Vinculin knockout results in heart and brain defects during embryonic development.

The vinculin gene codes for a cytoskeletal protein, found in focal adhesion plaques and in cell-cell adherens junctions. Vinculin was inactivated by homologous recombination using a targeting vector in embryonic stem (ES) cells. The heterozygous ES cells were introduced into mice by established procedures to produce heterozygous animals that were normal and fertile. No homozygous vinculin-/- embryos were born and analyses during the gestational period showed that the vinculin null embryos were small and abnormal from day E8 but some survived until E10. The most prominent defect was lack of midline fusion of the rostral neural tube, producing a cranial bilobular appearance and attenuation of cranial and spinal nerve development. Heart development was curtailed at E9.5, with severely reduced and akinetic myocardial and endocardial structures. Mutant embryos were 30-40% smaller, somites and limbs were retarded and ectodermal tissues were sparse and fragile. Fibroblasts (MEF) isolated from mutant embryos were shown to have reduced adhesion to fibronectin, vitronectin, laminin and collagen compared to wild-type levels. In addition, migration rates over these substrata were two-fold higher and the level of focal adhesion kinase (FAK) activity was three-fold higher. We conclude that vinculin is necessary for normal embryonic development, probably because of its role in the regulation of cell adhesion and locomotion, cell behaviors essential for normal embryonic morphogenesis, although specific roles in neural and cardiac development cannot be ruled out.

Animals↗
PubMed2005

Induction of immunological tolerance in chickens inoculated with xenogeneic antigens at an early stage of embryonic development.

To induce immunotolerance, laboratory chicken embryos were inoculated with casein via embryonic blood vessel microinjection or with bovine serum albumin (BSA) by either embryonic blood vessel or yolk sac injection. All hatched chickens were challenged with the same protein four times at 10-day intervals beginning at 3 weeks old. Serum anti-casein and anti-BSA antibodies were analyzed by enzyme-linked immunosorbent assay (ELISA). Significantly reduced serum specific antibody, demonstrating immunotolerance, was observed in 53.8% of chickens exposed to casein in embryo by microinjection at 65-70 h of incubation; and in 62.5% (inoculating at 65-67 h of incubation) and 33.33% (inoculating at 67-70 h of incubation) of chickens exposed to BSA. Tolerant chickens presented in those groups inoculated with BSA at 5-7 days of embryogenesis by in ovo injection. The results showed tolerance could be induced by injecting xenogeneic protein into early developing embryo by both inoculation methods.

Animals↗
PubMed1991

Paxillin is a major phosphotyrosine-containing protein during embryonic development.

Phosphotyrosine-containing proteins were immunoprecipitated from embryonic chicken tissue extracts using anti-phosphotyrosine antibody coupled to agarose beads. Major phosphotyrosine-containing proteins of 110, 70, and 50 kD were observed following blotting with anti-phosphotyrosine antibody. The 70-kD band was selectively removed from the samples by precipitation with antibodies to the focal adhesion protein paxillin, therefore identifying paxillin as one of the major tyrosine kinase substrates during chick embryonic organogenesis. The tyrosine phosphorylation of paxillin is regulated developmentally: during embryogenesis, a marked decrease in its phosphotyrosine content was observed, although the total level of paxillin remained essentially constant. Approximately 20% of the paxillin was phosphorylated on tyrosine in the early embryo. In contrast, tyrosine phosphorylation of paxillin was undetectable in the adult. A similar profile of phosphotyrosine-containing proteins was identified in rat embryos. Paxillin was also found to be a major phosphotyrosine-containing protein in the rat embryo. These data suggest that the regulated phosphorylation of tyrosine residues on paxillin may perform a critical role in controlling cell and tissue cytoarchitecture rearrangement during vertebrate development.

Animals↗
PubMed1986

Expression of the antigens recognized by monoclonal antibodies to human amnion (GB4, GB9, GB11) on the rabbit eye during embryonic development.

Three monoclonal antibodies to human amnion (GB4, GB9 and GB11) which recognized well-defined structures of the adult rabbit eye were used to study the embryonic eye development. The reactivity of GB4 could be identified on the migrating neural crest cells under the corneal epithelium at 2 weeks of gestation. At 3 weeks of gestation, the conjunctival epithelium, corneal epithelium and corneal endothelium reacted with GB4. In the newborn rabbit, the corneal epithelium was reactive with GB9 instead of GB4; corneal endothelium was positive with GB4 at this stage, but gradually became negative in the adult rabbit; the subcapsular epithelium of the lens was recognized by GB4 when it changed from pseudostratified to simple cuboidal epithelium. During early embryonic life, GB11 was positive on the external retinal layer of the optic cup and lens vesicle. In the adult, GB11 reacted only with the pigmented epithelium of the ciliary processes. The results of this study demonstrated that the expression of antigens recognized by GB4, GB9 and GB11 could be mapped according to the epithelial differentiation of the rabbit eye during embryogenesis.

Amnion↗