LIM-homeobox transcription factors regulate neuronal dendritic morphogenesis in subtype-specific manner.

在神经系统中，祖细胞中转录因子的表达调节着细胞类型的分化。然而，这些转录因子是否调节后来的发育事件仍然是一个悬而未决的问题。我们发现两个lim同源结构域转录因子Lim1和Islet1在不同的视网膜水平细胞亚型中表达（Lim1: I型，Islet1: II/III型）。在迁移后水平细胞中过表达Islet1可抑制内源性Lim1的表达，增加具有II型细胞特异性形态的细胞。抑制Lim1功能干扰I型水平细胞轴突形态发生。我们的研究结果表明，在视网膜发育后期，水平细胞的亚型特异性形态发生需要lim同源结构域转录因子。

In nervous system, transcription factor expression in progenitor cells regulates cell type specification. However, whether or not these transcription factors regulate later developmental events remains an open question. We found that two LIM-homeodomain transcription factors, Lim1 and Islet1, are expressed in distinct subtype of retinal horizontal cells (Lim1 : type I, Islet1 : type II/III). Overexpression of Islet1 in post-migratory horizontal cells repressed endogenous Lim1 expression and increased the cells with type II cell specific morphology. Inhibition of Lim1 function perturbed axonal morphogenesis of type I horizontal cells. Our results suggest that LIM-homeodomain transcription factors are required for subtype-specific morphogenesis of horizontal cells at later stages of retinal development.