Studies on physiological functions of ovalbumin and occurrence of neural tube defects due to deprivation of ovalbumin in chick embryo.

卵清蛋白被归类为丝氨酸蛋白酶抑制剂（serine protease inhibitor，serpin）的同系物，但除了可能是一种营养源外，对其功能知之甚少。我们已经表明，在胚胎发育过程中，卵清蛋白（N-卵清蛋白）的天然分子被掺入组织中而不降解，同时经历构型变化成为称为“HS-卵清蛋白”的热稳定形式。“在这里，为了研究HS-卵清蛋白的不可或缺性，我们利用了一种体外培养方法，通过这种方法，从第7阶段（神经管开始闭合之前）的鸡蛋中分离出的鸡胚可以正常发育长达24小时。当内源性的残余卵清蛋白被添加抗卵清蛋白的多克隆IgG阻断时，分离的胚胎变得不规则，特别是在脑组织中，导致所谓的神经管缺陷（NTD）。NTD的胚胎显示细胞凋亡和细胞增殖的信号减少。此外，IgG处理的胚胎通过加入足够的 ...更多信息 量的HS-卵清蛋白加入培养基中，获得正常形态而没有NTD。HS-卵白蛋白表现出比N-卵白蛋白和S-卵白蛋白更高的拯救率，后者是另一种热稳定的对应物，其通过在体外加热N-卵白蛋白而人工发生。这些结果表明，卵清蛋白（特别是在HS形式）是必不可少的胚胎器官发生，包括神经管的形成。目前的结果还表明，卵清蛋白剥夺的胚胎给出了减少原位信号的TUNEL试剂和PCNA/c-Myc蛋白，这分别反映了细胞凋亡和细胞增殖的变化。此外，卵清蛋白剥夺还影响了胚胎中许多基因的表达，包括与形态发生相关的分化诱导因子。FGF 8和slug的表达明显下降，而BMP 4和Pax 3的表达增加了3倍以上。然而，这些改变是否是形态发生异常的原因或结果尚不清楚。由于卵清蛋白属于丝氨酸蛋白酶抑制剂超家族，因此它可能与某些关键的分化诱导因子直接相互作用。少

Ovalbumin has been classified as a homolog of serine protease inhibitor (serpin), although little is known of its function except that it may be a nutrient source. We have shown that, during embryonic development, native molecules of ovalbumin (N-ovalbumin) are incorporated into tissues without degradation while undergoing configurational changes into a heat-stable form called 'HS-ovalbumin.' Here, to investigate the indispensability of HS-ovalbumin, we utilized an in vitro culture method by which chick embryos isolated from eggs at Stage 7 (before the neural tube begins to close) could develop normally for up to 24h. When endogenous, remnant ovalbumin was blocked by adding anti-ovalbumin polyclonal IgG to the medium, the isolated embryos became irregular particularly in brain tissue, resulting in the so-called neural tube deficiency (NTD). The embryos with NTD showed reduced signals for apoptosis and cell proliferation. Moreover, IgG-treated embryos were rescued by adding a sufficient … More amount of HS-ovalbumin to the medium, attaining normal morphologies without NTD. HS-ovalbumin exhibited a higher rescue rate than N-ovalbumin and S-ovalbumin, the latter being another heat-stable counterpart that occurs artificially by heating N-ovalbumin in vitro. These results indicate that ovalbumin (particularly in the HS-form) is essential in embryonic organogenesis, including neural tube formation. present results show also that the ovalbumin-deprived embryos gave decreased in situ signals for TUNEL reagents and for PCNA/c-Myc proteins, which mirror changes in apoptosis and cell proliferation, respectively. Also the ovalbumin deprival affect the embryos on many gene expressions including differentiation-inducing factors related to morphogenesis. Expressions of FGF8 and slug have decreased markedly, whereas those of BMP4 and Pax3 have increased over 3-fold. However, whether each of these alterations is a cause or a result of morphogenetic aberrancy is unclear. Since ovalbumin belongs to the serpin superfamily, there is a possibility that it shows direct interactions with some crucial differentiation-inducing factors. Less