Identification and functional analysis of early gene expression induced by circadian light-resetting in Drosophila

Adeolu B. Adewoye, Charalambos P. Kyriacou, Eran Tauber

Research output: Contribution to journalArticlepeer-review


Background: The environmental light-dark cycle is the dominant cue that maintains 24-h biological rhythms in multicellular organisms. In Drosophila, light entrainment is mediated by the photosensitive protein CRYPTOCHROME, but the role and extent of transcription regulation in light resetting of the dipteran clock is yet unknown. Given the broad transcriptional changes in response to light previously identified in mammals, we have sought to analyse light-induced global transcriptional changes in the fly's head by using Affymetrix microarrays. Flies were subjected to a 30-min light pulse during the early night (3h after lights-off), a stimulus which causes a substantial phase delay of the circadian rhythm. We then analysed changes in gene expression 1h after the light stimulus. Results: We identified 200 genes whose transcripts were significantly altered in response to the light pulse at a false discovery rate cut-off of 10%. Analysis of these genes and their biological functions suggests the involvement of at least six biological processes in light-induced delay phase shifts of rhythmic activities. These processes include signalling, ion channel transport, receptor activity, synaptic organisation, signal transduction, and chromatin remodelling. Using RNAi, the expression of 22 genes was downregulated in the clock neurons, leading to significant effects on circadian output. For example, while continuous light normally causes arrhythmicity in wild-type flies, the knockdown of Kr-h1, Nipped-A, Thor, nrv1, Nf1, CG11155 (ionotropic glutamate receptor), and Fmr1 resulted in flies that were rhythmic, suggesting a disruption in the light input pathway to the clock. Conclusions: Our analysis provides a first insight into the early responsive genes that are activated by light and their contribution to light resetting of the Drosophila clock. The analysis suggests multiple domains and pathways that might be associated with light entrainment, including a mechanism that was represented by a light-activated set of chromatin remodelling genes.

Original languageEnglish
Article number570
JournalBMC Genomics
Issue number1
StatePublished - 1 Aug 2015
Externally publishedYes

Bibliographical note

Funding Information:
We thank the six anonymous reviewers whose comments and suggestions helped improve and clarify this manuscript. This work was funded by grants from BBSRC BB/G02085X/1 to ET. ABA was supported by the 6th Framework Project EUCLOCK (no. 018741) to CPK. We thank the University of Leicester Genome core facility.

Publisher Copyright:
© 2015 Adewoye et al.


  • Chromatin remodelling
  • Circadian clock
  • Circadian phase shift
  • Drosophila
  • Gene expression
  • Light entrainment
  • Microarrays
  • Transcriptome

ASJC Scopus subject areas

  • Biotechnology
  • Genetics


Dive into the research topics of 'Identification and functional analysis of early gene expression induced by circadian light-resetting in Drosophila'. Together they form a unique fingerprint.

Cite this