Understanding Circadian Output Networks in Neurospora Crassa

作者：Rigzin Dekhang · 发表于：OakTrust (Texas A&M University Libraries) · 年份：2015 · 研究领域：Plant and Biological Electrophysiology Studies

The Neurospora crassa circadian clock is based on a highly regulated molecular negative feedback loop, similar to molecular clocks in all eukaryotes. A core component of the N. crassa molecular clock is the White Collar complex (WCC), composed of the blue light photoreceptor WC-1 and its partner WC-2. The WCC serves as a master regulator that controls light signaling, and the precise timing of target gene expression. Up to 40% of the eukaryote genome is under the control of the clock at the level of transcript abundance, but the molecular links between the core oscillator and downstream target genes, as well as the mechanisms controlling the phase of rhythmic gene expression, are not understood. Using chromatin immunoprecipitation coupled to high-throughput sequencing (ChIP-seq), about 400 binding sites for the WCC were identified throughout the N. crassa genome. We found that 24 transcription factors (TFs) were significantly enriched among the direct WCC target genes. As expected for genes that are controlled by the WCC, the first-tier TFs are both clock- and light-regulated. These data led to the hypothesis that the WCC functions to control rhythms in TFs, which in turn control rhythmicity and phase of downstream target genes and processes.\n\nTo test this hypothesis, the first-tier TF ADV-1 (Arrested Development-1) was investigated in detail to characterize the downstream circadian genetic network. ADV-1 target genes were identified using ChIP- and RNA-seq, and as expected...