Patterning of chick brain vesicles as revealed by peanut agglutinin and cholinesterases.
Patterning of chick brain vesicles as revealed by peanut agglutinin and cholinesterases.
复制标题
花生凝集素和胆碱酯酶揭示的小鸡脑泡的模式。
作者：
P. Layer;R. Alber
随着初级脑泡的出现，鸡后脑中单个菱形核的分化直接发生。在HH9的前脑收缩后，HH9和HH10之间几乎同时建立了一系列大小减小的小泡，包括中脑、4个先天(R2-R5)和1个后天(R6/R7)菱形脑。因此，脑神经管被腹侧嵌入到中胚层PNA结合基质中，该基质特别聚集在囊泡收缩部位下面，如HH9的前脑和HH13的小脑菱形核R1与R2的分离所示。随后的后脑分化阶段用胆碱酯酶(AChE)和花生凝集素组织化学、BrdU和轴突特异性G4抗体分析。以前，两对菱形单体(R4+R5，R2+R3)的分化始于R4，紧随其后的是R2。两对的尾部菱形核均延迟(R5、R3)。然后，后菱形核被细分，因此R7在R6之前分化。因此，耳囊直接附近的发育被延迟(R5、R6)。R7是最后一个以尾部为界的菱形核。基于这些发现，我们推测可能调节鸡胚中菱形球形成的两个过程：(A)建立主要脑囊泡的早期喙尾波，(B)从耳囊发出的从吻端和尾端发出的重叠的成对分段。小脑菱形核的分离是一个较晚的步骤。
Differentiation of individual rhombomeres of the chicken hindbrain directly follows the emergence of primary brain vesicles. Immediately after the constriction of the prosencephalon at HH9, a series of vesicles of decreasing size is established almost simultaneously between HH9 and HH10, including mesencephalon, four preotic (R2-R5) and one postotic (R6/R7) rhombomeres. Thereby, the cranial neural tube is ventrally embedded in a mesodermal PNA-binding matrix that particularly accumulates underneath vesicular constriction sites, as demonstrated for the segregation of the prosencephalon at HH9 and the cerebellar rhombomere R1 from R2 at HH13. The subsequent period of hindbrain differentiation is analyzed by cholinesterase (AChE, BChE) and peanut lectin histochemistry, by the BrdU and the neurite-specific G4 antibodies. Preotically, differentiation of two pairs of rhombomeres (R4 + R5, R2 + R3) starts in R4, immediately followed by R2. The caudal rhombomeres of both pairs are delayed (R5, R3). Then the postotic rhombomere is subdivided, whereby R7 differentiates before R6. Thus, the development in the direct vicinity of the otic vesicle is delayed (R5, R6). R7 is the last rhombomere that is demarcated caudally. Based on these findings, we postulate two processes that may regulate rhombomere formation in the chicken embryo: (a) an early rostrocaudal wave establishing the major brain vesicles, (b) a superimposed pairwise segmentation emanating rostrally and caudally from the otic vesicle. The segregation of the cerebellar rhombomere is a late step.