Rodríguez-Moldes Isabel, Ferreiro-Galve Susana, Carrera Iván, Sueiro Catalina, Candal Eva, Mazan Sylvie, Anadón Ramón
Department of Cell Biology and Ecology, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain.
Neurosci Lett. 2008 Feb 20;432(2):105-10. doi: 10.1016/j.neulet.2007.11.059. Epub 2007 Dec 7.
We have studied the patterns of cell proliferation, regional organization and differentiation in the cerebellar body of embryos and juveniles of two shark species by immunohistochemistry with antibodies against proliferating cell nuclear antigen (PCNA), Pax6, reelin (RELN), GABA, glutamic acid decarboxylase (GAD) and calretinin (CR). The organization of Pax6-expressing cells was also studied by in situ hybridization. Our results reveal that a transient secondary matrix zone, the external germinal layer, is formed in sharks at early stages of cerebellar development and is the source of the earliest Pax6-expressing (granule) cells. Later in development, new granule Pax6-expressing cells arise from medial proliferation zones and accumulate medially in the granular eminences. The GABAergic components appear very early, and show clear regional differences. The medial proliferation zones remain active even in adults. Taken together, the proliferation and differentiation markers used in the present study highlight striking similarities during development between the cerebellar body of elasmobranchs and the cerebella of tetrapods. These results show the importance of elasmobranch models to reconstruct the evolutionary developmental history of the vertebrate cerebellum.
我们通过使用针对增殖细胞核抗原（PCNA）、Pax6、reelin（RELN）、GABA、谷氨酸脱羧酶（GAD）和钙结合蛋白（CR）的抗体进行免疫组织化学，研究了两种鲨鱼胚胎和幼体小脑体中的细胞增殖、区域组织和分化模式。还通过原位杂交研究了表达Pax6的细胞的组织情况。我们的结果表明，在鲨鱼小脑发育的早期阶段形成了一个短暂的次级基质区，即外颗粒层，它是最早表达Pax6的（颗粒）细胞的来源。在发育后期，新的表达Pax6的颗粒细胞从中部增殖区产生，并在内侧颗粒隆起中积累。GABA能成分很早就出现了，并表现出明显的区域差异。即使在成年鲨鱼中，中部增殖区仍然活跃。综上所述，本研究中使用的增殖和分化标志物突出了软骨鱼类小脑体与四足动物小脑在发育过程中的显著相似性。这些结果表明了软骨鱼类模型对于重建脊椎动物小脑进化发育史具有重要意义。
