McCurdy H M
J Cell Biol. 1969 Nov;43(2):220-8. doi: 10.1083/jcb.43.2.220.
The DOPA-reaction was used to identify tyrosinase in the nucleus and cytoplasm of the neural crest melanoblast of Taricha torosa, the California newt. In this urodele there is a nuclear DOPA-positive response during the normal embryonic development from the late blastula stage to the nucleus of the early melanocyte. During the gastrula stages, all nuclei of this newt are DOPA-positive. This positive nuclear response fades away after the formation of the neural crest, save in the melanoblasts. The only cells that give a positive DOPA marking in the cytoplasm are the melanoblasts. This cytoplasmic reaction appears while the melanoblast nucleus still gives a DOPA-positive reaction. Tyrosinase activity, as marked by unlabeled DOPA, has ceased in the fully mature melanocyte. The red nuclei, seen in some of the animals in the maturing melanocyte and adjacent tissues, may be in the hallachrome stage of melanin formation. There is a diffuse distribution of DOPA reactivity in the resting nucleus, and an adherence of the DOPA-marking in the region of the dividing chromosomes in the mitosis of DOPA-positive nuclei of the melanoblast. These observations suggest that tyrosinase may be among the chromosomally bound enzymes of the chromatin space.
多巴反应被用于鉴定加利福尼亚蝾螈（Taricha torosa）神经嵴成黑素细胞的细胞核和细胞质中的酪氨酸酶。在这种有尾两栖动物中，从囊胚晚期到早期黑素细胞的细胞核，在正常胚胎发育过程中存在核多巴阳性反应。在原肠胚阶段，这种蝾螈的所有细胞核都是多巴阳性的。这种阳性核反应在神经嵴形成后消失，仅在成黑素细胞中存在。细胞质中产生多巴阳性标记的唯一细胞是成黑素细胞。这种细胞质反应在成黑素细胞核仍呈多巴阳性反应时出现。在完全成熟的黑素细胞中，以未标记的多巴标记的酪氨酸酶活性已经停止。在一些成熟黑素细胞和相邻组织的动物中看到的红色细胞核，可能处于黑色素形成的褐黑素阶段。在静止细胞核中多巴反应性呈弥漫分布，在成黑素细胞多巴阳性细胞核有丝分裂时，多巴标记附着在分裂染色体区域。这些观察结果表明，酪氨酸酶可能是染色质空间中与染色体结合的酶之一。
