Neural precursor cells differentiating in the absence of Rb exhibit delayed terminal mitosis deregulated E2F 1 and 3 activity
Neural precursor cells differentiating in the absence of Rb exhibit delayed terminal mitosis deregulated E2F 1 and 3 activity
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DOI：
10.1006/dbio.1998.9162
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发表时间：
1999-03-15
影响因子：
2.7
通讯作者：
Slack, RS
中科院分区：
文献类型：
--
作者：
Callaghan, DA;Dong, L;Slack, RS
携带视网膜母细胞瘤（Rb）基因零突变的胚胎严重的神经功能缺陷表明Rb在神经发生中起着至关重要的作用。当发育中的神经元经历细胞凋亡时，从rb缺陷胚胎中培养的神经前体细胞表现出分化和存活。为了确定Rb是否是调节终有丝分裂的内在途径的必要调节剂，我们检测了来自Rb缺陷小鼠的原代皮质祖细胞和bfgf依赖性神经干细胞的终分化。尽管Rb -/-神经前体细胞能够在体外分化，但我们发现这些细胞相对于野生型细胞在有丝分裂末期表现出明显的延迟。此外，体外存活的Br -/-细胞表现出p107的上调，这在E2F3复合物中发现。这表明p107可能部分补偿了神经前体细胞中Rb的缺失。腺病毒介导的E1A n端突变体对Rb家族蛋白的功能性消融导致Rb缺陷细胞凋亡，这与其他Rb家族蛋白可能促进分化和存活的解释一致。虽然p107在神经前体细胞中上调并与Rb靶点E2F3相互作用，但我们的研究结果表明，它显然不能恢复正常的E2F调节。rb缺陷细胞在分化过程中表现出e2f1和3活性的显著增强，同时E2F诱导基因的异常表达。在这些研究中，我们发现Rb对神经前体细胞中e2f1和3活性的调控以及终有丝分裂的发生至关重要。(C) 1999学术出版社。
The severe neurological deficit in embryos carrying null mutations for the retinoblastoma (Rb) gene suggests that Rb plays a crucial role in neurogenesis. While developing neurons undergo apoptosis in vivo neural precursor cells cultured from Rb-deficient embryos appear to differentiate and survive. To determine whether Rb is an essential regulator of the intrinsic pathway modulating terminal mitosis we examined the terminal differentiation of primary cortical progenitor cells and bFGF-dependent neural stem cells derived from Rb-deficient mice. Although Rb -/- neural precursor cells are able to differentiate in vitro we show that these cells exhibit a significant delay in terminal mitosis relative to wild-type cells. Furthermore, Br -/- cells surviving in vitro exhibit and upregulation of p107 that is found in complexes with E2F3. This suggests that p107 may partially compensate for the loss of Rb in neural precursor cells. Functional ablation of Rb family proteins by adenovirus-mediated delivery of an E1A N-terminal mutant results in apoptosis in Rb-deficient cells, consistent with the interpretation that other Rb family proteins may facilitate differentiation and survival. While p107 is upregulated and interacts with the putative Rb target E2F3 in neural precursor cells, our results indicate that it clearly cannot restore normal E2F regulation. Rb-deficient cells exhibit a significant enhancement of E2F 1 and 3 activity throughout differentiation concomitant with the aberrant expression of E2F-inducible genes. In these studies we show that Rb is essential for the regulation of E2F 1 and 3 activity as well as the onset of terminal mitosis in neural precursor cells. (C) 1999 Academic Press.