The Drosophila visual system integrates input from 800 ommatidia and extracts different features in stereotypically connected optic ganglia. The development of the Drosophila visual system is controlled by gene regulatory networks that control the number of precursor cells, generate neuronal diversity by integrating spatial and temporal information, coordinate the timing of retinal and optic lobe cell differentiation, and determine distinct synaptic targets of each cell type. In this chapter, we describe the known gene regulatory networks involved in the development of the different parts of the visual system and explore general components in these gene networks. Finally, we discuss the advantages of the fly visual system as a model for gene regulatory network discovery in the era of single-cell transcriptomics.
Amyotrophic lateral sclerosis is a neurodegenerative disease that causes progressive paralysis that is lethal and incurable to date. In this article, we discovered a developmentally critical microRNA cluster, mir-17~92, plays a role in the vulnerability of spinal motor neurons and supplementing this microRNA cluster can prolong the life expectancy in a mouse disease model.
In this article, we demonstrated that a long non-coding RNA, Meg3, is required to establish the boundary between two genes that mark spinal motor neurons from different body segments. To suppress the expression of caudal genes from expressing in rostral segments, Meg3 forms a complex with PRC2 to suppress them, the catalytic complex that marks histone with repressive modificication H3K27me3.