This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Add to Saved Citations Download to citation manager Request Permissions Request Reprints Add to My Marked Citations Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (23) Citing Articles via Google Scholar Citing Articles via Scopus Google Scholar Articles by Houl, J. H. Articles by Hardin, P. E. Search for Related Content PubMed PubMed Citation Articles by Houl, J. H. Articles by Hardin, P. E. Social Bookmarking                         What's this?

Drosophila CLOCK Is Constitutively Expressed in Circadian Oscillator and Non-Oscillator Cells

Department of Biology and Biochemistry, University of Houston, Houston, TX

Wangjie Yu

Department of Biology and Biochemistry, University of Houston, Houston, TX

Scott M. Dudek

Center for Human Genetics Research, Vanderbilt University, 519 Light Hall, Nashville, TN 37232-0700

Paul E. Hardin

Department of Biology, Texas A&M University, 3258 TAMU, College Station, TX 77845-3258, phardin{at}mail.bio.tamu.edu

CLOCK (CLK) is a core component of the transcriptional feedback loops that comprise the circadian timekeeping mechanism in Drosophila. As a heterodimer with CYCLE (CYC), CLK binds E-boxes to activate the transcription of rhythmically expressed genes within and downstream of the circadian clock, but this activation unexpectedly occurs at times when CLK is at its lowest levels on Western blots. Recent studies demonstrate that CLK also regulates nonrhythmic gene expression and behaviors. Despite the critical roles CLK plays within and outside the circadian clock, its spatial expression pattern has not been characterized. Using a newly developed CLK antibody, the authors show that CLK is coexpressed with PERIOD (PER) in canonical oscillator cells throughout the head and body. In contrast to PER, however, the levels of CLK immunoreactivity do not cycle in intensity, CLK is detected primarily in the nucleus throughout the circadian cycle, and CLK is expressed in non-oscillator cells within the lateral and dorsal brain, including Kenyon cells, which mediate various forms of learning and memory. These results indicate that constitutive levels of nuclear CLK regulate rhythmic transcription in circadian oscillator cells and suggest that CLK contributes to other behavioral processes by regulating gene expression in non-oscillator cells.

Key Words: CLOCK • Drosophila • circadian • oscillator cells • non-oscillator cells

Journal of Biological Rhythms, Vol. 21, No. 2, 93-103 (2006)
DOI: 10.1177/0748730405283697


CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				J. O. Gummadova, G. A. Coutts, and N. R. J. Glossop Analysis of the Drosophila Clock Promoter Reveals Heterogeneity in Expression between Subgroups of Central Oscillator Cells and Identifies a Novel Enhancer Region J Biol Rhythms, October 1, 2009; 24(5): 353 - 367. [Abstract] [PDF]

				V. L. Kilman and R. Allada Genetic Analysis of Ectopic Circadian Clock Induction in Drosophila J Biol Rhythms, October 1, 2009; 24(5): 368 - 378. [Abstract] [PDF]

				X. Zheng, K. Koh, M. Sowcik, C. J. Smith, D. Chen, M. N. Wu, and A. Sehgal An Isoform-Specific Mutant Reveals a Role of PDP1{varepsilon} in the Circadian Oscillator J. Neurosci., September 2, 2009; 29(35): 10920 - 10927. [Abstract] [Full Text] [PDF]

				H.-C. Hung, C. Maurer, D. Zorn, W.-L. Chang, and F. Weber Sequential and Compartment-specific Phosphorylation Controls the Life Cycle of the Circadian CLOCK Protein J. Biol. Chem., August 28, 2009; 284(35): 23734 - 23742. [Abstract] [Full Text] [PDF]

				W. Yu, H. Zheng, J. L. Price, and P. E. Hardin DOUBLETIME Plays a Noncatalytic Role To Mediate CLOCK Phosphorylation and Repress CLOCK-Dependent Transcription within the Drosophila Circadian Clock Mol. Cell. Biol., March 15, 2009; 29(6): 1452 - 1458. [Abstract] [Full Text] [PDF]

				L. C. Lyons and G. Roman Circadian modulation of short-term memory in Drosophila Learn. Mem., December 30, 2008; 16(1): 19 - 27. [Abstract] [Full Text] [PDF]

				J. Benito, J. H. Houl, G. W. Roman, and P. E. Hardin The Blue-Light Photoreceptor CRYPTOCHROME Is Expressed in a Subset of Circadian Oscillator Neurons in the Drosophila CNS J Biol Rhythms, August 1, 2008; 23(4): 296 - 307. [Abstract] [PDF]

				B. Richier, C. Michard-Vanhee, A. Lamouroux, C. Papin, and F. Rouyer The Clockwork Orange Drosophila Protein Functions as Both an Activator and a Repressor of Clock Gene Expression J Biol Rhythms, April 1, 2008; 23(2): 103 - 116. [Abstract] [PDF]

				X. Zheng and A. Sehgal Probing the Relative Importance of Molecular Oscillations in the Circadian Clock Genetics, March 1, 2008; 178(3): 1147 - 1155. [Abstract] [Full Text] [PDF]

				Hyuk Wan Ko, S. DiMassa, Eun Young Kim, K. Bae, and I. Edery Cis-Combination of the Classic perS and perL Mutations Results in Arrhythmic Drosophila with Ectopic Accumulation of Hyperphosphorylated PERIOD Protein J Biol Rhythms, December 1, 2007; 22(6): 488 - 501. [Abstract] [PDF]

				E. Y. Kim, H. W. Ko, W. Yu, P. E. Hardin, and I. Edery A DOUBLETIME Kinase Binding Domain on the Drosophila PERIOD Protein Is Essential for Its Hyperphosphorylation, Transcriptional Repression, and Circadian Clock Function Mol. Cell. Biol., July 1, 2007; 27(13): 5014 - 5028. [Abstract] [Full Text] [PDF]

				A. Matsumoto, M. Ukai-Tadenuma, R. G. Yamada, J. Houl, K. D. Uno, T. Kasukawa, B. Dauwalder, T. Q. Itoh, K. Takahashi, R. Ueda, et al. A functional genomics strategy reveals clockwork orange as a transcriptional regulator in the Drosophila circadian clock Genes & Dev., July 1, 2007; 21(13): 1687 - 1700. [Abstract] [Full Text] [PDF]

				S. Kadener, D. Stoleru, M. McDonald, P. Nawathean, and M. Rosbash Clockwork Orange is a transcriptional repressor and a new Drosophila circadian pacemaker component Genes & Dev., July 1, 2007; 21(13): 1675 - 1686. [Abstract] [Full Text] [PDF]

				Z. Ding, A. J. Millar, A. M. Davis, and S. J. Davis TIME FOR COFFEE Encodes a Nuclear Regulator in the Arabidopsis thaliana Circadian Clock PLANT CELL, May 1, 2007; 19(5): 1522 - 1536. [Abstract] [Full Text] [PDF]

				J. Benito, H. Zheng, and P. E. Hardin PDP1{varepsilon} Functions Downstream of the Circadian Oscillator to Mediate Behavioral Rhythms J. Neurosci., March 7, 2007; 27(10): 2539 - 2547. [Abstract] [Full Text] [PDF]

				M. Rosbash, S. Bradley, S. Kadener, Y. Li, W. Luo, J. S. Menet, E. Nagoshi, K. Palm, R. Schoer, Y. Shang, et al. Transcriptional Feedback and Definition of the Circadian Pacemaker in Drosophila and Animals Cold Spring Harb Symp Quant Biol, January 1, 2007; 72(0): 75 - 83. [Abstract] [PDF]

				J. Benito, H. Zheng, F. S. Ng, and P. E. Hardin Transcriptional Feedback Loop Regulation, Function, and Ontogeny in Drosophila Cold Spring Harb Symp Quant Biol, January 1, 2007; 72(0): 437 - 444. [Abstract] [PDF]

				K. Bae and I. Edery Regulating a Circadian Clock's Period, Phase and Amplitude by Phosphorylation: Insights from Drosophila J. Biochem., November 1, 2006; 140(5): 609 - 617. [Abstract] [Full Text] [PDF]