Huff R, Furst A, Mahowald A P
Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106.
Dev Biol. 1989 Jul;134(1):146-57. doi: 10.1016/0012-1606(89)90085-7.
Isolated neuroblasts from gastrula-stage Drosophila embryos divide and differentiate in vitro to produce clonally derived clusters of neurons. Both serotonin and dopamine are expressed within these cultures in patterns that are similar to their distributions in vivo. Clusters containing serotonergic neurons are generally distinct from those with dopaminergic neurons, suggesting that different neuroblasts produce neurons with these phenotypes. The appearance of each transmitter correlates with transcription of dopa decarboxylase in the transmitter-positive cells. The developmental program leading to the appearance of either serotonergic or dopaminergic neurons is different for each transmitter type. Thus, serotonergic cells are progeny of early neuroblast divisions, whereas dopaminergics arise throughout the lineage. Inhibition of cell division, but not nuclear division, with cytochalasin B demonstrates that the expression of the serotonin phenotype requires a determined number of DNA replications. These experiments establish that neuroblasts, as soon as they are formed during early gastrulation events in Drosophila, are already determined for the subsequent expression of transmitter phenotype.
从原肠胚期果蝇胚胎中分离出的神经母细胞在体外进行分裂和分化，产生克隆衍生的神经元簇。血清素和多巴胺在这些培养物中的表达模式与其在体内的分布相似。含有血清素能神经元的簇通常与含有多巴胺能神经元的簇不同，这表明不同的神经母细胞产生具有这些表型的神经元。每种递质的出现与递质阳性细胞中多巴脱羧酶的转录相关。导致血清素能或多巴胺能神经元出现的发育程序因每种递质类型而异。因此，血清素能细胞是早期神经母细胞分裂的后代，而多巴胺能细胞则出现在整个谱系中。用细胞松弛素B抑制细胞分裂而非核分裂表明，血清素表型的表达需要一定数量的DNA复制。这些实验表明，在果蝇早期原肠胚形成过程中一旦形成，神经母细胞就已经决定了随后递质表型的表达。
