Gabilondo Hugo, Losada-Pérez María, Monedero Ignacio, Torres-Herráez Arturo, Molina Isabel, Torroja Laura, Benito-Sipos Jonathan
Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049, Madrid, Spain.
Cell Tissue Res. 2014 Nov;358(2):621-6. doi: 10.1007/s00441-014-1965-y. Epub 2014 Aug 17.
Studies in the Drosophila embryonic NB4-2 lineage have suggested that the transcription factor Klumpfuss (Klu) functions within embryonic neuroblast lineages to differentiate between the identities of two adjacent ganglion mother cells (GMCs). However, because of the limited lineage markers available, these observations have been made only for the NB4-2 lineage. Recent findings have placed this transcription factor in the vanguard of Drosophila neural stem cell biology by demonstrating that Klu is necessary for larval neuroblast growth and self-renewal. Here, we have studied the role of klu in an incipient model in order to address basic mechanisms of neural specification: the Va system. None of the previously reported roles of Klu satisfactorily explain our observations. Unexpectedly, in this lineage, klu is necessary for differentiating between the fates of the two neurons born from a unique GMC; klu mutants produce two B-type cells, rather than one B-type (Notch-OFF) and one A-type (Notch-ON) cell. Additionally, our results demonstrate that Klu operates in the GMC and/or in the newly born neuron, but not in the neuroblast. Unlike in larval neuroblasts in which Klu is an executor of Notch signaling, we have found that Klu does not lie downstream of the Notch pathway in this cell division context.
对果蝇胚胎NB4-2细胞谱系的研究表明，转录因子Klumpfuss（Klu）在胚胎神经母细胞谱系中发挥作用，以区分两个相邻神经节母细胞（GMC）的身份。然而，由于可用的谱系标记有限，这些观察仅针对NB4-2细胞谱系进行。最近的研究结果将这种转录因子置于果蝇神经干细胞生物学的前沿，表明Klu是幼虫神经母细胞生长和自我更新所必需的。在这里，我们研究了klu在一个初始模型中的作用，以探讨神经特化的基本机制：Va系统。Klu先前报道的任何作用都不能令人满意地解释我们的观察结果。出乎意料的是，在这个细胞谱系中，klu对于区分由一个独特的GMC产生的两个神经元的命运是必需的；klu突变体产生两个B型细胞，而不是一个B型（Notch关闭）和一个A型（Notch开启）细胞。此外，我们的结果表明，Klu在GMC和/或新生神经元中起作用，但不在神经母细胞中起作用。与Klu在幼虫神经母细胞中作为Notch信号的执行者不同，我们发现在这种细胞分裂背景下，Klu并不位于Notch通路的下游。
