日本科学家在最新出版的英国《自然》杂志上报告说，鹌鹑等在春天繁殖的动物，其体内腺体会根据春天光照时间延长的特点，向大脑传递春天来临的消息，促使生殖腺为生殖做好准备。
日本名古屋大学副教授吉村崇等人在实验中，调整对鹌鹑的光照时间，先是光照时间较短，相当于冬天的状态，然后逐渐延长光照时间到相当于春天的状态。在此过程中，科学家密切观察鹌鹑下丘脑的变化。
下丘脑是大脑皮层下调节内脏活动和内分泌活动的较高级神经中枢。研究发现，当光照时间延长到春天的状态时，下丘脑下方的下垂体隆起部分就开始分泌甲状腺刺激激素，激素向大脑特定区域传递信息后，可促使一种能让生殖腺发育的基因活跃起来。
吉村崇说，感知春天来临的机制在脊椎动物身上是有共性的，如果能调节甲状腺刺激激素进而控制繁殖时间，就有可能提高家畜和鱼类的繁殖能力。
生物谷推荐原始出处：
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: sprat@cnb.uam.es).
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.
