TY - JOUR T1 - Identification of novel genes involved in light-dependent CRY degradation through a genome-wide RNAi screen. JF - Genes Dev Y1 - 2008 A1 - Sathyanarayanan, Sriram A1 - Zheng, Xiangzhong A1 - Kumar, Shailesh A1 - Chen, Chun-Hong A1 - Chen, Dechun A1 - Hay, Bruce A1 - Sehgal, Amita KW - Animals KW - Cells, Cultured KW - Circadian Rhythm KW - CLOCK Proteins KW - Drosophila KW - Light KW - Photoreceptor Cells, Invertebrate KW - RNA Interference KW - Trans-Activators AB -

Circadian clocks regulate many different physiological processes and synchronize these to environmental light:dark cycles. In Drosophila, light is transmitted to the clock by a circadian blue light photoreceptor CRYPTOCHROME (CRY). In response to light, CRY promotes the degradation of the circadian clock protein TIMELESS (TIM) and then is itself degraded. To identify novel genes involved in circadian entrainment, we performed an unbiased genome-wide screen in Drosophila cells using a sensitive and quantitative assay that measures light-induced degradation of CRY. We systematically knocked down the expression of approximately 21,000 genes and identified those that regulate CRY stability. These genes include ubiquitin ligases, signal transduction molecules, and redox molecules. Many of the genes identified in the screen are specific for CRY degradation and do not affect degradation of the TIM protein in response to light, suggesting that, for the most part, these two pathways are distinct. We further validated the effect of three candidate genes on CRY stability in vivo by assaying flies mutant for each of these genes. This work identifies a novel regulatory network involved in light-dependent CRY degradation and demonstrates the power of a genome-wide RNAi approach for understanding circadian biology.

VL - 22 IS - 11 U1 - http://www.ncbi.nlm.nih.gov/pubmed/18519643?dopt=Abstract ER -