■动物区分不同波长的光的能力(即,色觉)是中介的,在某种程度上,通过表达具有不同吸收光谱的视蛋白的感光细胞子集。在果蝇R7光感受器中,视紫红质分子的表达,Rh3或Rh4,是由无旋转转录因子介导的随机进程决定的。这项研究的目的是使用全基因组关联研究(GWAS)与通过RNA-Seq的转录组分析配对,确定调节R7细胞命运和视蛋白选择的其他因素。
■我们检测了来自果蝇遗传参考小组的完全测序自交系的一部分中的Rh3和Rh4表达,并进行了GWAS以鉴定42个天然存在的多态性-接近28个候选基因-显著影响R7视蛋白表达。网络分析揭示了相关候选基因之间的多种潜在相互作用,无骨和它的伙伴。在二次RNAi筛选中进一步验证GWAS候选物,其鉴定了显著降低表达R7光感受器的Rh3的比例的12个品系。最后,使用RNA-Seq,我们证明,除了四个GWAS候选物外,所有这些都在关键的发育时间点在p视网膜中表达,并且五个在七个无突变体中的917个差异表达基因中,缺乏R7细胞。
■集体,这些结果表明,相对简单的,R7视蛋白表达基础的二元细胞命运决定受较大的调节,更复杂的监管因素网络。特别感兴趣的是具有先前表征的神经元功能的候选基因的子集,包括神经发生。神经变性,光感受器发育,轴突生长和指导,突触发生,和突触功能。
UNASSIGNED: An animal\'s ability to discriminate between differing wavelengths of light (i.e., color vision) is mediated, in part, by a subset of photoreceptor cells that express opsins with distinct absorption spectra. In Drosophila R7 photoreceptors, expression of the rhodopsin molecules, Rh3 or Rh4, is determined by a stochastic process mediated by the transcription factor spineless. The goal of this study was to identify additional factors that regulate R7 cell fate and opsin choice using a Genome Wide Association Study (GWAS) paired with transcriptome analysis via RNA-Seq.
UNASSIGNED: We examined Rh3 and Rh4 expression in a subset of fully-sequenced inbred strains from the Drosophila Genetic Reference Panel and performed a GWAS to identify 42 naturally-occurring polymorphisms-in proximity to 28 candidate genes-that significantly influence R7 opsin expression. Network analysis revealed multiple potential interactions between the associated candidate genes, spineless and its partners. GWAS candidates were further validated in a secondary RNAi screen which identified 12 lines that significantly reduce the proportion of Rh3 expressing R7 photoreceptors. Finally, using RNA-Seq, we demonstrated that all but four of the GWAS candidates are expressed in the pupal retina at a critical developmental time point and that five are among the 917 differentially expressed genes in sevenless mutants, which lack R7 cells.
UNASSIGNED: Collectively, these results suggest that the relatively simple, binary cell fate decision underlying R7 opsin expression is modulated by a larger, more complex network of regulatory factors. Of particular interest are a subset of candidate genes with previously characterized neuronal functions including neurogenesis, neurodegeneration, photoreceptor development, axon growth and guidance, synaptogenesis, and synaptic function.