Larouche Matt, Che Priscilla M, Hawkes Richard
Department of Cell Biology and Anatomy, Genes and Development Research Group, Hotchkiss Brain Institute, Faculty of Medicine, The University of Calgary, Alberta T2N 4N1, Canada.
J Comp Neurol. 2006 Jan 10;494(2):215-27. doi: 10.1002/cne.20791.
Markers that reveal the parasagittal organization of cerebellar Purkinje cells may be grouped into two classes based on the time during development when they are expressed. In mice, early-onset markers are defined by their heterogeneous expression in clusters of Purkinje cells during late embryogenesis, which disappears shortly following birth. Late-onset markers are generally not expressed until about 1 week after birth and do not reach a stable striped expression pattern until about 3 weeks postnatally. Currently, no endogenous markers are known that are heterogeneously expressed in the temporal gap between these two classes. Here we present immunocytochemical evidence that parasagittal stripes of Purkinje cells express a member of the calpacitin protein family, neurogranin, possibly from as early as embryonic day (E) 13 and definitively from E15, in a pattern that persists up to postnatal day (P) 20. Neurogranin is thus the first endogenous marker of a Purkinje cell subset capable of bridging the temporal gap between the early- and late-onset patterns. In the early neonate, up to five pairs of neurogranin-immunopositive Purkinje cell stripes run parasagittally through the cerebellum, with the exact number dependent on the rostrocaudal position. Expression is lost during postnatal development in a transverse zone-dependent fashion. Purkinje cells in the central and nodular zones lose neurogranin expression between approximately P4 and P6, whereas expression in the posterior zone persists until approximately P20. Neurogranin immunoreactivity will be a valuable tool in helping to clarify the relationships between early- and late-onset patterns.
根据表达时间，可将揭示小脑浦肯野细胞旁矢状组织的标志物分为两类。在小鼠中，早期标志物的定义是其在胚胎后期浦肯野细胞簇中的异质性表达，出生后不久这种表达就会消失。晚期标志物通常直到出生后约1周才表达，直到出生后约3周才达到稳定的条纹状表达模式。目前，尚不知道有内源性标志物在这两类标志物的时间间隔内进行异质性表达。在此，我们提供免疫细胞化学证据表明，浦肯野细胞的旁矢状条纹表达钙结合蛋白家族的一个成员——神经颗粒素，最早可能从胚胎第13天（E13）开始表达，确定从E15开始表达，这种表达模式一直持续到出生后第20天（P20）。因此，神经颗粒素是第一个能够弥合早期和晚期表达模式时间间隔的浦肯野细胞亚群的内源性标志物。在早期新生儿中，多达五对神经颗粒素免疫阳性的浦肯野细胞条纹旁矢状贯穿小脑，确切数量取决于前后位置。在出生后发育过程中，表达以横向区域依赖的方式消失。中央区和小结区的浦肯野细胞在大约P4和P6之间失去神经颗粒素表达，而后区的表达持续到大约P20。神经颗粒素免疫反应性将成为有助于阐明早期和晚期表达模式之间关系的有价值工具。
