Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 100 N. Plastira St., 70013 Heraklion, Crete, Greece.
Development. 2010 Jan;137(2):191-201. doi: 10.1242/dev.043604.
bHLH-O proteins are a subfamily of the basic-helix-loop-helix transcription factors characterized by an 'Orange' protein-protein interaction domain. Typical members are the Hairy/E(spl), or Hes, proteins, well studied in their ability, among others, to suppress neuronal differentiation in both invertebrates and vertebrates. Hes proteins are often effectors of Notch signalling. In vertebrates, another bHLH-O protein group, the Hey proteins, have also been shown to be Notch targets and to interact with Hes. We have studied the single Drosophila Hey orthologue. We show that it is primarily expressed in a subset of newly born neurons, which receive Notch signalling during their birth. Unlike in vertebrates, however, Hey is not expressed in precursor cells and does not block neuronal differentiation. It rather promotes one of two alternative fates that sibling neurons adopt at birth. Although in the majority of cases Hey is a Notch target, it is also expressed independently of Notch in some lineages, most notably the larval mushroom body. The availability of Hey as a Notch readout has allowed us to study Notch signalling during the genesis of secondary neurons in the larval central nervous system.
bHLH-O 蛋白是碱性螺旋-环-螺旋转录因子的一个亚家族，其特征是具有“橙色”蛋白-蛋白相互作用结构域。典型的成员是 Hairy/E(spl)或 Hes 蛋白，它们在抑制无脊椎动物和脊椎动物中的神经元分化方面的能力得到了广泛研究。Hes 蛋白通常是 Notch 信号的效应物。在脊椎动物中，另一个 bHLH-O 蛋白家族 Hey 蛋白也被证明是 Notch 的靶标，并与 Hes 相互作用。我们研究了果蝇的单一 Hey 直系同源物。我们表明，它主要在一组新出生的神经元中表达，这些神经元在出生时接受 Notch 信号。然而，与脊椎动物不同的是，Hey 不在前体细胞中表达，也不会阻止神经元分化。相反，它促进了出生时兄弟姐妹神经元采用的两种替代命运之一。尽管在大多数情况下 Hey 是 Notch 的靶标，但它在某些谱系中也独立于 Notch 表达，尤其是在幼虫蘑菇体中。Hey 作为 Notch 读出的可用性使我们能够研究幼虫中枢神经系统中次级神经元发生过程中的 Notch 信号。
