Amat J A, Fields K L, Schubart U K
Department of Neurology, Albert Einstein College of Medicine, Bronx, NY 10461.
Brain Res Dev Brain Res. 1991 Jun 21;60(2):205-18. doi: 10.1016/0165-3806(91)90049-o.
p19 is an evolutionarily highly conserved 19-kDa cytosolic protein that undergoes hormonally regulated phosphorylation in a variety of mammalian cells. Its expression is abundant in brain and testis and is developmentally regulated. Here we have used immunocytochemistry to define the cell types expressing p19 in the rat CNS during pre- and postnatal development. p19-like immunoreactivity appears in young postmitotic neurons in the mantle zone of the neural tube on embryonic day 12-13. Subsequently, it is abundant in most, if not all, early immature forms of both neurons and glia and declines to undetectable levels in fully differentiated cells. In adult brain, strong p19-like immunoreactivity remains detectable in selective regions, primarily where production of glia and neurons is known to persist, such as the subventricular zone of olfactory bulb and lateral ventricle, and the dentate gyrus. The abundance of p19 mRNA, determined by Northern blot analysis of selected brain regions, parallels the distribution of p19 assessed by immunocytochemistry, suggesting that control of p19 expression is pretranslational. Together with previous findings on the transient expression of p19 during spermatogenesis, the present data suggest that expression of p19 occurs in a number of cell lineages in a differentiation stage-dependent manner. In brain, p19 represents a new marker that may prove valuable for defining immature cell populations.
p19是一种在进化上高度保守的19 kDa胞质蛋白，在多种哺乳动物细胞中会经历激素调节的磷酸化过程。它在脑和睾丸中表达丰富，且受发育调控。在此，我们运用免疫细胞化学方法来确定在大鼠中枢神经系统（CNS）出生前和出生后发育过程中表达p19的细胞类型。p19样免疫反应性在胚胎第12 - 13天神经管套层区的年轻有丝分裂后神经元中出现。随后，它在大多数（即便不是全部）早期未成熟的神经元和神经胶质细胞形式中都很丰富，并在完全分化的细胞中降至无法检测的水平。在成体脑中，在一些特定区域仍可检测到强烈的p19样免疫反应性，主要是已知神经胶质细胞和神经元产生持续存在的区域，如嗅球和侧脑室的室下区以及齿状回。通过对选定脑区进行Northern印迹分析确定的p19 mRNA丰度，与通过免疫细胞化学评估的p19分布情况相似，这表明p19表达的调控发生在翻译前阶段。结合之前关于p19在精子发生过程中短暂表达的研究结果，目前的数据表明p19的表达以分化阶段依赖的方式发生在多个细胞谱系中。在脑中，p19代表了一种新的标志物，可能对界定未成熟细胞群体具有重要价值。
