如果能够通过基因调控使蚕吐出各种颜色的蚕丝，那么我们还需要给丝绸染色干什么呢。
这是日本东京大学的科学及们的目标，他们希望能够通过基因工程让蚕吐出指定颜色的蚕丝。他们的结果发表在最新的《Proceedings of the National Academy of Sciences of the United States》上。
文章的第一作者，东京大学的Takashi Sakudoh说：“对蚕的色素传输系统的了解，使得我们有可能通过基因调控来控制蚕丝的颜色和色素比例。”
自然界中，蚕茧的颜色有白色、黄色、稻草色、橙红色、粉红色和绿色。丝绸的颜色来自于桑蚕吃桑树叶时对自然色素的吸收。
日本的科学家们发现吐白色丝的蚕的Y基因产生了变异。DNA的片断被删除了。而Y基因会使桑蚕能够吸收桑树叶中的类胡萝卜素——一种黄色的化学物质。
科学家们发现这些变异的蚕会产生没有功能的类胡萝卜素捆绑蛋白（CBP）——一种已知会辅助色素吸收的蛋白。
因此，研究人员通过基因工程技术把原始的Y基因引入变异的蚕，这些蚕会产生有功能的CBP，于是就吐出了黄色的蚕丝。并且在多轮杂交后，蚕丝的黄色会更加地鲜艳。
日本科学家的初步研究结果掌握了黄色蚕丝的控制方法，相信随着研究的深入，当人们掌握了控制多种颜色的方法后，我们的丝绸就不再需要染色了。
原文链接：http://www.physorg.com/news97810726.html
刘乐译自：physorg.com
原始出处:
Published online before print March 19, 2007, 10.1073/pnas.0701331104
PNAS | March 27, 2007 | vol. 104 | no. 13 | 5668-5673
Wnt/-catenin/CBP signaling maintains long-term murine embryonic stem cell pluripotency
Tomoyuki Miyabayashi*,, Jia-Ling Teo,, Masashi Yamamoto*, Michael McMillan,, Cu Nguyen,, and Michael Kahn,,,¶
*Central R&D Laboratories, Asahi Kasei Corporation, Shizuoka 416-8501, Japan; Institute for Chemical Genomics, 600 Broadway, Suite 580, Seattle, WA 98122; and ¶Department of Pharmacology, University of Washington, Seattle, WA 98195
Communicated by Edwin G. Krebs, University of Washington School of Medicine, Seattle, WA, February 14, 2007 (received for review October 23, 2006)
Abstract
Embryonic stem cells (ESCs) represent an important research tool and a potential resource for regenerative medicine. Generally, ESCs are cocultured with a supportive feeder cell layer of murine embryonic fibroblasts, which maintain the ESCs' capacity for self-renewal and block spontaneous differentiation. These cumbersome conditions, as well as the risk of xenobiotic contamination of human ESCs grown on murine embryonic fibroblasts, make it a priority to develop chemically defined methods that can be safely used for the expansion of ESCs. Using a high-throughput, cell-based assay, we identified the small molecule IQ-1 that allows for the Wnt/-catenin-driven long-term expansion of mouse ESCs and prevents spontaneous differentiation. We demonstrate that IQ-1, by targeting the PR72/130 subunit of the serine/threonine phosphatase PP2A, prevents -catenin from switching coactivator usage from CBP to p300. The increase in -catenin/CBP-mediated transcription at the expense of -catenin/p300-mediated transcription is critical for the maintenance of murine stem cell pluripotency.
p300 | PP2A | Wnt signaling | Nkd | small molecule
