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）的表达和定位采用4%多聚甲醛浸泡固定，石蜡包埋，连续切片。用抗兔EGF-R抗体免疫染色，二氨基联苯胺/H_2O_2反应后检测。EGF-R的特征性组织特异性定位被注意到，消化道和呼吸道、软骨、肾脏和表皮的上皮细胞对EGF-R的反应产物呈强烈阳性。增殖上皮组织具有选择性反应，提示表皮生长因子可能在人胚胎上皮组织的增殖和分化中起关键作用。EGF-R在小鼠胎儿融合腭架中的表达。免疫组织化学方法检测了12-14天小鼠胎儿腭中EGF-R的表达。在腭上皮及其下层间质中检测到EGF-R的免疫反应产物，并注意到空间异质性和时间序列，这似乎与腭发育过程密切相关。妊娠雌鼠经维甲酸处理后，腭裂畸形中经常产生EGF-R的表达。孕鼠口服80 ~ 100 mg/kg全反式维甲酸，用免疫组织化学方法检测胎儿EGF-R水平。处理组胎儿腭组织中EGF-R的表达明显高于对照组胎儿相应组织。维甲酸似乎扰乱了正常的EGF-R表达调控，从而抑制腭架融合。目前的研究表明，表皮生长因子及其相关原癌基因可能在哺乳动物的形态发生中起重要作用。

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.