GSBS Student Publications

Student Author(s)

Quan Yuan

GSBS Program

Neuroscience

UMMS Affiliation

Department of Neurobiology; Emery Lab; Reppert Lab; Graduate School of Biomedical Sciences, Neuroscience Program

Date

1-11-2008

Document Type

Article

Medical Subject Headings

Animals; Brain; Butterflies; Cell Line; *Circadian Rhythm; Drosophila; Drosophila Proteins; Eye Proteins; Flavoproteins; Flight, Animal; Molecular Sequence Data; Mutation; Photoreceptor Cells, Invertebrate; Receptors, G-Protein-Coupled; *Sunlight; Transgenes

Disciplines

Neuroscience and Neurobiology

Abstract

The circadian clock plays a vital role in monarch butterfly (Danaus plexippus) migration by providing the timing component of time-compensated sun compass orientation, a process that is important for successful navigation. We therefore evaluated the monarch clockwork by focusing on the functions of a Drosophila-like cryptochrome (cry), designated cry1, and a vertebrate-like cry, designated cry2, that are both expressed in the butterfly and by placing these genes in the context of other relevant clock genes in vivo. We found that similar temporal patterns of clock gene expression and protein levels occur in the heads, as occur in DpN1 cells, of a monarch cell line that contains a light-driven clock. CRY1 mediates TIMELESS degradation by light in DpN1 cells, and a light-induced TIMELESS decrease occurs in putative clock cells in the pars lateralis (PL) in the brain. Moreover, monarch cry1 transgenes partially rescue both biochemical and behavioral light-input defects in cry(b) mutant Drosophila. CRY2 is the major transcriptional repressor of CLOCK:CYCLE-mediated transcription in DpN1 cells, and endogenous CRY2 potently inhibits transcription without involvement of PERIOD. CRY2 is co-localized with clock proteins in the PL, and there it translocates to the nucleus at the appropriate time for transcriptional repression. We also discovered CRY2-positive neural projections that oscillate in the central complex. The results define a novel, CRY-centric clock mechanism in the monarch in which CRY1 likely functions as a blue-light photoreceptor for entrainment, whereas CRY2 functions within the clockwork as the transcriptional repressor of a negative transcriptional feedback loop. Our data further suggest that CRY2 may have a dual role in the monarch butterfly's brain-as a core clock element and as an output that regulates circadian activity in the central complex, the likely site of the sun compass.

Rights and Permissions

Citation: PLoS Biol. 2008 Jan;6(1):e4. Link to article on publisher's site

DOI of Published Version

10.1371/journal.pbio.0060004

Related Resources

Link to Article in PubMed

Journal Title

PLoS biology

PubMed ID

18184036

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.