Porta Sílvia, Martí Eulàlia, de la Luna Susana, Arbonés Maria L
Center for Genomic Regulation (CRG), UPF, Dr Aiguader 88, E-08003 Barcelona, Spain.
Eur J Neurosci. 2007 Sep;26(5):1213-26. doi: 10.1111/j.1460-9568.2007.05749.x.
RCANs, also called Down Syndrome Critical Region-1 (DSCR1)-like proteins, Modulatory Calcineurin Interacting Proteins (MCIPs) or calcipressins, are regulators of calcineurin, a Ca(2+)-dependent protein phosphatase involved in several neuronal functions. Despite the potential importance of the RCAN proteins in brain physiology, very little is known about their relative abundance and distribution patterns in the central nervous system. In this study we report the expression and distribution of RCAN mRNA transcripts and proteins in the mouse brain. RT-PCR and Western blot analysis showed that all Rcan mRNAs (Rcan1-1, Rcan1-2, Rcan2-1, Rcan2-3 and Rcan3) and their corresponding protein products (RCAN1-L, RCAN1-S, RCAN2-L, RCAN2-S and RCAN3) are present in every adult mouse brain region examined. All protein isoforms are also expressed in these same brain regions at early postnatal stages. Within regions, RCAN1-L, RCAN1-S, RCAN2-L and RCAN3 are differentially expressed depending on the region and developmental stage, whereas RCAN2-S is distributed homogeneously. Detailed immunohistochemical analysis revealed significant differences in the cellular and subcellular distributions of RCAN proteins. In the adult, RCAN1 was mainly expressed in the neuropil throughout the brain. Although at lower levels, RCAN3 was also detected throughout the neuropil. In contrast, RCAN2 was highly expressed in scattered neurons, in both the nucleus and the cytoplasm. Interestingly, RCAN2 is the only member of the RCAN family that was detected in glial cells. Finally, the expression patterns of RCANs at early postnatal stages differed from those of the adult, in different brain areas, in both their distributions and relative abundance, suggesting that the expression of these proteins could be regulated during neuronal differentiation. The nonoverlapping expression patterns of the RCAN proteins shown here highlight the existence of different physiological scenarios and therefore suggest different RCAN functional activities in the brain, depending on the cellular context and developmental stage.
RCAN蛋白，也被称为唐氏综合征关键区域-1（DSCR1）样蛋白、钙调神经磷酸酶调节相互作用蛋白（MCIPs）或钙调蛋白，是钙调神经磷酸酶的调节剂，钙调神经磷酸酶是一种参与多种神经元功能的Ca(2+)依赖性蛋白磷酸酶。尽管RCAN蛋白在脑生理学中具有潜在的重要性，但关于它们在中枢神经系统中的相对丰度和分布模式却知之甚少。在本研究中，我们报告了RCAN mRNA转录本和蛋白在小鼠脑中的表达和分布。逆转录聚合酶链反应（RT-PCR）和蛋白质免疫印迹分析表明，所有Rcan mRNA（Rcan1-1、Rcan1-2、Rcan2-1、Rcan2-3和Rcan3）及其相应的蛋白产物（RCAN1-L、RCAN1-S、RCAN2-L、RCAN2-S和RCAN3）在每个检测的成年小鼠脑区中均有存在。所有蛋白异构体在出生后早期阶段的相同脑区中也有表达。在各脑区内，RCAN1-L、RCAN1-S、RCAN2-L和RCAN3根据脑区和发育阶段的不同而差异表达，而RCAN2-S则均匀分布。详细的免疫组织化学分析揭示了RCAN蛋白在细胞和亚细胞分布上的显著差异。在成体中，RCAN1主要在全脑的神经毡中表达。尽管水平较低，但在整个神经毡中也检测到了RCAN3。相比之下，RCAN2在分散的神经元中高度表达，在细胞核和细胞质中均有表达。有趣的是，RCAN2是RCAN家族中唯一在胶质细胞中被检测到的成员。最后，RCAN在出生后早期阶段的表达模式在不同脑区的分布和相对丰度方面与成体不同，这表明这些蛋白的表达可能在神经元分化过程中受到调控。此处所示的RCAN蛋白的非重叠表达模式突出了不同生理情况的存在，因此表明在脑中根据细胞环境和发育阶段存在不同的RCAN功能活动。
