冬去春來，白晝在不知不覺中變得越來越長,。人類可能不會察覺這些微妙的細(xì)節(jié),，然而鳥類卻無時無刻不在監(jiān)視著這些細(xì)微的變化。
據(jù)美國《科學(xué)》雜志在線新聞報(bào)道,，研究人員發(fā)現(xiàn),，鳥類通過監(jiān)控季節(jié)的變化來知曉何時應(yīng)該交配。如今,，經(jīng)過幾十年的研究,，研究人員報(bào)告說，他們終于確定了一種能夠讓鳥類知道春天來了的蛋白質(zhì)——脊椎動物遠(yuǎn)古視蛋白（VA opsin）,。由它在大腦中形成的感光器對于圖中這只知更鳥的成功繁殖是至關(guān)重要的,。研究人員在上周的《現(xiàn)代生物學(xué)》雜志網(wǎng)絡(luò)版上報(bào)告了這一發(fā)現(xiàn)。（生物谷Bioon.com）
生物谷推薦原始出處：
Current Biology, 06 August 2009 doi:10.1016/j.cub.2009.06.066
VA Opsin-Based Photoreceptors in the Hypothalamus of Birds
Stephanie Halford1,3,Susana S. Pires1,3,Michael Turton1,Lei Zheng1,Irene González-Menéndez2,Wayne L. Davies1,Stuart N. Peirson1,José M. García-Fernández2,Mark W. Hankins1,,andRussell G. Foster1,,
1 Circadian and Visual Neuroscience, Nuffield Laboratory of Ophthalmology, University of Oxford, Headley Way, Oxford OX3 9DU, UK
2 Departamento de Morfología y Biología Celular, Universidad de Oviedo, 33006 Oviedo, Spain
Studies in the 1930s demonstrated that birds possess photoreceptors that are located within the hypothalamus and regulate photoperiodic responses to day length [1,2]. Most recently, photoperiod has been shown to alter the activity of the pars tuberalis to release thyrotrophin, which ultimately drives a reproductive response [3,4]. Despite these significant findings, the cellular and molecular identity of the hypothalamic photoreceptors has remained a mystery. Action spectra implicated an opsin-based photopigment system [5], but further identification based on rod- or cone-opsin probes failed, suggesting the utilization of a novel opsin [6]. The vertebrate ancient (VA) opsin photopigments were isolated in 1997 [7,8] but were thought to havea restricted taxonomic distribution, confined to the agnatha and teleost fish. Here, we report the isolation of VA opsin from chicken and show that the two isoforms spliced from this gene (cVAL and cVA) are capable of forming functional photopigments. Further, we show that VA opsin is expressed within a population of hypothalamic neurons with extensive projections to the median eminence. These results provide the most complete cellular and molecular description of a deep brain photoreceptor in any vertebrate and strongly implicate VA opsin in mediating the avian photoperiodic response.
