日本科學家在最新出版的英國《自然》雜志上報告說，鵪鶉等在春天繁殖的動物,，其體內(nèi)腺體會根據(jù)春天光照時間延長的特點，向大腦傳遞春天來臨的消息,，促使生殖腺為生殖做好準備,。
日本名古屋大學副教授吉村崇等人在實驗中，調(diào)整對鵪鶉的光照時間,，先是光照時間較短,，相當于冬天的狀態(tài)，然后逐漸延長光照時間到相當于春天的狀態(tài),。在此過程中,，科學家密切觀察鵪鶉下丘腦的變化。
下丘腦是大腦皮層下調(diào)節(jié)內(nèi)臟活動和內(nèi)分泌活動的較高級神經(jīng)中樞,。研究發(fā)現(xiàn),，當光照時間延長到春天的狀態(tài)時，下丘腦下方的下垂體隆起部分就開始分泌甲狀腺刺激激素,，激素向大腦特定區(qū)域傳遞信息后,，可促使一種能讓生殖腺發(fā)育的基因活躍起來。
吉村崇說,，感知春天來臨的機制在脊椎動物身上是有共性的,，如果能調(diào)節(jié)甲狀腺刺激激素進而控制繁殖時間，就有可能提高家畜和魚類的繁殖能力,。
生物谷推薦原始出處：
Nature 451, 480-484 (24 January 2008) | doi:10.1038/nature06520;
Received 28 September 2007; Accepted 28 November 2007
A molecular framework for light and gibberellin control of cell elongation
Miguel de Lucas1,4, Jean-Michel Davière1,4, Mariana Rodríguez-Falcón1,4, Mariela Pontin1, Juan Manuel Iglesias-Pedraz1, Séverine Lorrain2, Christian Fankhauser2, Miguel Angel Blázquez3, Elena Titarenko1 & Salomé Prat1
Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología-CSIC, Campus Univ. Autónoma de Madrid, Cantoblanco. c/ Darwin 3, 28049 Madrid, Spain
Centre for Integrative Genomics, University of Lausanne, Genopode Building, CH-1015 Lausanne, Switzerland
Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia, Consejo Superior de Investigaciones Científicas, 46022 Valencia, Spain
These authors contributed equally to this work.
Correspondence to: Salomé Prat1 Correspondence and requests for materials should be addressed to S.P. (Email: [email protected]).
Cell elongation during seedling development is antagonistically regulated by light and gibberellins (GAs)1, 2. Light induces photomorphogenesis, leading to inhibition of hypocotyl growth, whereas GAs promote etiolated growth, characterized by increased hypocotyl elongation. The mechanism underlying this antagonistic interaction remains unclear. Here we report on the central role of the Arabidopsis thaliana nuclear transcription factor PIF4 (encoded by PHYTOCHROME INTERACTING FACTOR 4)3 in the positive control of genes mediating cell elongation and show that this factor is negatively regulated by the light photoreceptor phyB (ref. 4) and by DELLA proteins that have a key repressor function in GA signalling5. Our results demonstrate that PIF4 is destabilized by phyB in the light and that DELLAs block PIF4 transcriptional activity by binding the DNA-recognition domain of this factor. We show that GAs abrogate such repression by promoting DELLA destabilization, and therefore cause a concomitant accumulation of free PIF4 in the nucleus. Consistent with this model, intermediate hypocotyl lengths were observed in transgenic plants over-accumulating both DELLAs and PIF4. Destabilization of this factor by phyB, together with its inactivation by DELLAs, constitutes a protein interaction framework that explains how plants integrate both light and GA signals to optimize growth and development in response to changing environments.
