Identification of Circadian-Clock-Regulated Enhancers and Genes of Drosophila melanogaster by Transposon Mobilization and Luciferase Reporting of Cyclical Gene Expression

Corresponding author: Ralf Stanewsky, Institut für Zoologie, Lehrstuhl für Entwicklungsbiologie, Universitätsstraße 31, 93040 Regensburg, Germany., ralf.stanewsky{at}biologie.uni-regensburg.de (E-mail)

Communicating editor: J. J. LOROS

A new way was developed to isolate rhythmically expressed genes in Drosophila by modifying the classic enhancer-trap method. We constructed a P element containing sequences that encode firefly luciferase as a reporter for oscillating gene expression in live flies. After generation of 1176 autosomal insertion lines, bioluminescence screening revealed rhythmic reporter-gene activity in 6% of these strains. Rhythmically fluctuating reporter levels were shown to be altered by clock mutations in genes that specify various circadian transcription factors or repressors. Intriguingly, rhythmic luminescence in certain lines was affected by only a subset of the pacemaker mutations. By isolating genes near 13 of the transposon insertions and determining their temporal mRNA expression pattern, we found that four of the loci adjacent to the trapped enhancers are rhythmically expressed. Therefore, this approach is suitable for identifying genetic loci regulated by the circadian clock. One transposon insert caused a mutation in the rhythmically expressed gene numb. This novel numb allele, as well as previously described ones, was shown to affect the fly's rhythm of locomotor activity. In addition to its known role in cell fate determination, this gene and the phosphotyrosine-binding protein it encodes are likely to function in the circadian system.

This article has been cited by other articles:

				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]

				J. P. Masly, C. D. Jones, M. A. F. Noor, J. Locke, and H. A. Orr Gene transposition as a cause of hybrid sterility in Drosophila. Science, September 8, 2006; 313(5792): 1448 - 1450. [Abstract] [Full Text] [PDF]

				C. Wulbeck, G. Szabo, O. T. Shafer, C. Helfrich-Forster, and R. Stanewsky The Novel Drosophila timblind Mutation Affects Behavioral Rhythms but Not Periodic Eclosion Genetics, February 1, 2005; 169(2): 751 - 766. [Abstract] [Full Text] [PDF]

				T. P. Michael and C. R. McClung Enhancer Trapping Reveals Widespread Circadian Clock Transcriptional Control in Arabidopsis Plant Physiology, June 1, 2003; 132(2): 629 - 639. [Abstract] [Full Text] [PDF]

				M. F. Ceriani, J. B. Hogenesch, M. Yanovsky, S. Panda, M. Straume, and S. A. Kay Genome-Wide Expression Analysis in Drosophila Reveals Genes Controlling Circadian Behavior J. Neurosci., November 1, 2002; 22(21): 9305 - 9319. [Abstract] [Full Text] [PDF]