Study on the role of epidermal growth factor receptor and protooncogenes in mammalian morphogenesis

1.人胚胎组织中表皮生长因子受体(EGF-R)的表达与定位用抗兔EGF-R抗体进行免疫组化染色，经二氨基联胺/H_2O_2反应后进行检测。研究结果表明：1.EGF-R具有组织特异性定位特点，在消化管、呼吸道、软骨、肾脏和表皮上皮细胞中，EGF-R反应产物呈强阳性，提示表皮生长因子在人类胚胎上皮组织的增殖和分化中可能起关键作用。EGF-R在小鼠胚胎融合腭架中的表达用免疫组织化学方法检测12-14天小鼠胚胎腭部中EGF-R的表达。EGF-R免疫反应产物在腭部上皮细胞和下层间充质中均可检测到，且具有空间异质性和时间序列特征，与腭裂形成过程密切相关。表皮生长因子受体在畸形发育中的表达如果用维甲酸治疗怀孕的雌性小鼠，常常会产生唇腭裂。给妊娠母鼠灌胃80~100 mg/kg全反式维甲酸，对其胎儿进行EGF-R免疫组织化学检测，结果显示，给药组胎儿腭部组织中EGF-R的表达明显高于对照组。维甲酸似乎干扰了EGF-R表达的正常调节，从而抑制了腭架的融合。目前的研究表明，表皮生长因子和相关的原癌基因可能在哺乳动物的形态发生中发挥重要作用。

1. Expression and localization of epidermal growth factor receptor (EGF-R)in human embryonic tissuesHuman embryos of 3-8 weeks of gestation were immersion-fixed in 4% paraformaldehyde, embedded in paraffin, and serially sectioned. They were immunostained with anti-rabbit EGF-R antibody and examined after diaminobenzidine/H_2O_2 reaction. Characteristic tissue-specific localization of EGF-R was noted, and the epithelia of the digestive tube and respiratory tract, cartilage, kidney, and epidermis were strongly positive for the reactive products against EGF-R.Proliferating epithelial tissues were selectively reactive, suggesting that epidermal growth factor may play a key role in the proliferation and differentiation of epithelial tissues in human embryos.2. Expression of EGF-R in the fusing palatal shelves of mouse fetuses.Expression of EGF-R was examined immunohistochemically in the palates of days-12-14 mouse fetuses. Immunoreactive products against EGF-R was detected in palatal epithelia as well as underlying mesenchyme, and spatial heterogeneity and temporal sequence were noted which arppeared closely related to the palatogenetic process.3. Expression of EGF-R in dysmorphogenesisCleft Palate is frequently produced if pregnant female mice are treated with retinoic acid. Pregnant female mice were given orally 80-100 mg/kg all-trans retinoic acid and their fetuses were examined immurnohistochemically for EGF-R.The expression of EGF-R in the palatal tissue of treated fetuses were significantly more intense than in the corresponding tissue of control fetuses. It seems that retinoic acid disturbs the normal regulation of EGF-R expression and thereby inhibit the fusion of palatal shelves.The present study has shown that epidermal growth factor and related protooncogenes may play important role in mammalian morphogenesis.