Circadian clocks are endogenous cellular processes that control a wide variety of cellular, physiological, and behavioral activities in almost all organisms. The accuracy of these biological clocks is dependent on whether they can be synchronized (entrained) by the environment. Light is the most important environmental factor that entrains all circadian clocks from prokaryotes to mammals, and is known to regulate many important processes. Neurospora crassa, one of the best understood circadian clock systems, offers an excellent model for understanding the light entrainment mechanism at the molecular level. In Neurospora, the transcription factors WHITE COLLAR-1 (WC-1) and WC-2 are the positive elements in the circadian feedback loops that are essential for the clock function. Recently, we also identified WC-1, a FAD-containing protein, as the photoreceptor for circadian clock and other light responses. This finding established WC- 1 as the first known fungal blue light photoreceptor. The experiments in this project will address the molecular mechanisms of the light input pathway of the Neurospora circadian system.
In Specific Aim 1, we will determine how WC-1 senses light. We will use biochemical and structural approaches to test the hypotheses that the LOV domain of WC-1 binds FAD and undergoes reversible photocycles, and that light induces conformational changes of WC-1. WC-1 is phosphorylated in the dark and becomes hyperphosphorylated after light exposure, and the phosphorylation events may regulate its stability and activity. Therefore, in Specific Aim 2, we will determine the role of WC-1 phosphorylation in the light input and circadian clock. We will use mass spectrometry to determine WC-1 phosphorylation sites, and use genetic and biochemical approaches to understand the functions of phosphorylation and to identify the kinase(s) responsible.
In Specific Aim 3, we will identify novel factors that mediate light input in Neurospora. We will biochemically purify the large WC protein complex to identify novel factors, and we will screen for novel mutants with defects in light input and circadian clock. Together, these studies will help us to elucidate the light input mechanism of the Neurospora clock in genetic, biochemical, and molecular terms, and the information we obtain should provide fundamental information relevant to the light input pathway in other organisms

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
Project #
Application #
Study Section
Molecular, Cellular and Developmental Neurosciences 2 (MDCN)
Program Officer
Tompkins, Laurie
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Texas Sw Medical Center Dallas
Schools of Medicine
United States
Zip Code
Zhou, Zhipeng; Dang, Yunkun; Zhou, Mian et al. (2016) Codon usage is an important determinant of gene expression levels largely through its effects on transcription. Proc Natl Acad Sci U S A 113:E6117-E6125
Shi, Guangsen; Xie, Pancheng; Qu, Zhipeng et al. (2016) Distinct Roles of HDAC3 in the Core Circadian Negative Feedback Loop Are Critical for Clock Function. Cell Rep 14:823-834
Cha, Joonseok; Zhou, Mian; Liu, Yi (2015) Methods to study molecular mechanisms of the Neurospora circadian clock. Methods Enzymol 551:137-51
Yu, Chien-Hung; Dang, Yunkun; Zhou, Zhipeng et al. (2015) Codon Usage Influences the Local Rate of Translation Elongation to Regulate Co-translational Protein Folding. Mol Cell 59:744-54
Zhou, Mian; Wang, Tao; Fu, Jingjing et al. (2015) Nonoptimal codon usage influences protein structure in intrinsically disordered regions. Mol Microbiol 97:974-87
Xue, Zhihong; Ye, Qiaohong; Anson, Simon R et al. (2014) Transcriptional interference by antisense RNA is required for circadian clock function. Nature 514:650-3
Xu, Yao; Ma, Peijun; Shah, Premal et al. (2013) Non-optimal codon usage is a mechanism to achieve circadian clock conditionality. Nature 495:116-20
Yang, Qiuying; Li, Liande; Xue, Zhihong et al. (2013) Transcription of the major neurospora crassa microRNA-like small RNAs relies on RNA polymerase III. PLoS Genet 9:e1003227
Zhou, Zhipeng; Liu, Xiao; Hu, Qiwen et al. (2013) Suppression of WC-independent frequency transcription by RCO-1 is essential for Neurospora circadian clock. Proc Natl Acad Sci U S A 110:E4867-74
Shi, Guangsen; Xing, Lijuan; Liu, Zhiwei et al. (2013) Dual roles of FBXL3 in the mammalian circadian feedback loops are important for period determination and robustness of the clock. Proc Natl Acad Sci U S A 110:4750-5

Showing the most recent 10 out of 35 publications