Cytochemical and developemental studies on the color pattern formation

脊椎动物的颜色图案是由色素细胞在特定区域的特异性表达决定的。以非洲稻和非洲爪蟾为研究对象，研究了控制色素细胞分化和形态发生的因素。N-CAM和N-cadherin均存在于两种植物分化的黄细胞表面和米藻的白色细胞中，而黑细胞和彩虹细胞不表达这些分子。在体内，保证不同类型细胞之间连接形成染色质单位的关键分子可能与这些cam不同，仍有待鉴定。目前正在努力提高免疫电镜中抗原的保存和分辨率。爪蟾神经嵴细胞的分化在一定程度上是可控的；目前已经能够诱导或抑制黑色素细胞的分化，但我们仍然不知道如何有效地诱导其他类型的色素细胞。N-cadherin （135kd和112kd）在爪蟾胚胎的神经管（st.22）和后期的成色细胞（黑素细胞）中表达，但随着黑素细胞分化的进展逐渐减少。在内在因素方面，微管和静脉蛋白对水稻类细胞形态的维持起着重要作用，而在非洲爪蟾和黑鳍蛙中，肌动蛋白和肌球蛋白系统的参与是明显的。在两栖动物的发育过程中，细胞骨架结构的转变，即向静止状态的迁移，以及在变态过程中染色质单元形成过程中，应该进行进一步的研究。在虹膜细胞中，嘌呤血小板的形式直接关系到细胞是呈双极性还是扁平、不对称形式。

Color pattern of vertebrates is determined by specific expression of pigment cells in specific regions. Factors that control pigment cell differentiation and morphogenesis were examined using the cells of Oryzias latipes and Xenopus laevis. N-CAM and N-cadherin were found on cellular surface of differentiated xanthophores of both species and in leucophores of Oryzias while melanophores and iridophores did not express these molecules. Key molecules that guarantee attachment between the different types of cells to form tha chromatophore unit in vivo may be different from these CAMs and remain to be identified. The effort to improve antigen preservation and resolution in immunoelectromicroscopy is now being made. Differentiation of neural crest cells of Xenopus in culture can be controlled in some extent ; it is now able to induce or suppress melanophore differentiation but we still do not know the efficient way to induce the other types of pigment cells. N-cadherin (135 kd and 112 kd) is expressed in neural tube of Xenopus embryos (st.22) and in the chromatoblast (melanoblast) of later stage but gradually diminishes with the progress of melanophore differentiation. Regarding intrinsic factors, microtubules and vimentin are important to maitain cell morphology in Oryzias while in Xenopus and Rana melanophores, involvement of actin and myosin system is clearly shown. Further study onthe shift in cytoskeletal architecture during the development, i.e.migratory to sedentary state, and in the course of chromatophore unit formation during metamorphosis in amphibians should be carried out. In iridophores, the form of purine platelets is directly related whether the cell takes bipolar or flat, asymmetric form.