Magnetoreception : activated cryptochrome 1a concurs with magnetic orientation in birds

  • The radical pair model proposes that the avian magnetic compass is based on radical pair processes in the eye, with cryptochrome, a flavoprotein, suggested as receptor molecule. Cryptochrome 1a (Cry1a) is localized at the discs of the outer segments of the UV/violet cones of European robins and chickens. Here, we show the activation characteristics of a bird cryptochrome in vivo under natural conditions. We exposed chickens for 30 min to different light regimes and analysed the amount of Cry1a labelled with an antiserum against an epitope at the C-terminus of this protein. The staining after exposure to sunlight and to darkness indicated that the antiserum labels only an illuminated, activated form of Cry1a. Exposure to narrow-bandwidth lights of various wavelengths revealed activated Cry1a at UV, blue and turquoise light. With green and yellow, the amount of activated Cry1a was reduced, and with red, as in the dark, no activated Cry1a was labelled. Activated Cry1a is thus found at all those wavelengths at which birds can orient using their magnetic inclination compass, supporting the role of Cry1a as receptor molecule. The observation that activated Cry1a and well-oriented behaviour occur at 565 nm green light, a wavelength not absorbed by the fully oxidized form of cryptochrome, suggests that a state other than the previously suggested Trp/FAD radical pair formed during photoreduction is crucial for detecting magnetic directions.

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Author:Christine Nießner, Susanne DenzauGND, Katrin Stapput, Margaret Ahmad, Leo Peichl, Wolfgang WiltschkoGND, Roswitha WiltschkoORCiDGND
Pubmed Id:
Parent Title (English):Interface : journal of the Royal Society
Publisher:The Royal Society
Place of publication:London
Document Type:Article
Date of Publication (online):2013/11/06
Date of first Publication:2013/11/06
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2014/03/27
Tag:conformational change; cryptochrome 1a; flavin cycle; magnetic compass; photoreceptor
Page Number:7
© 2013 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License, which permits unrestricted use, provided the original author and source are credited.
Institutes:Biowissenschaften / Biowissenschaften
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 59 Tiere (Zoologie) / 590 Tiere (Zoologie)
Licence (German):License LogoCreative Commons - Namensnennung 3.0