被稱為“成形素”的某些分子的濃度梯度已知在胚胎形成過程中控制組織發(fā)育,。這種梯度怎樣形成是一個(gè)人們很不了解的問題,，Yu等人對(duì)此進(jìn)行了研究。他們采用一種用于在活體中對(duì)分子進(jìn)行成像的先進(jìn)的高精密度技術(shù)（熒光校正光譜）發(fā)現(xiàn),，活斑馬魚胚胎中的擴(kuò)散性FGF8“成形素”梯度由一個(gè)簡(jiǎn)單的源-匯機(jī)制形成,。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature 461, 533-536 (24 September 2009) | doi:10.1038/nature08391
Fgf8 morphogen gradient forms by a source-sink mechanism with freely diffusing molecules
Shuizi Rachel Yu1,3,4, Markus Burkhardt2,3,4, Matthias Nowak1,3, Jonas Ries2,3, Zdenk Petráek2,3, Steffen Scholpp1,5, Petra Schwille2,3 & Michael Brand1,3
1 Developmental Genetics, Biotechnology Center, TUD,
2 Biophysics, Biotechnology Center, TUD, and,
3 Center for Regenerative Therapies, TUD, Tatzberg 47-49, 01307 Dresden, Germany
4 These authors contributed equally to this work.
5 Present address: Institute of Toxicology and Genetics, Forschungszentrum Karlsruhe, D-76021 Karlsruhe, Germany.
Correspondence to: Petra Schwille2,3Michael Brand1,3 Correspondence and requests for materials should be addressed to P.S. or M.Br.
It is widely accepted that tissue differentiation and morphogenesis in multicellular organisms are regulated by tightly controlled concentration gradients of morphogens1, 2. How exactly these gradients are formed, however, remains unclear3, 4, 5, 6, 7, 8, 9, 10, 11, 12. Here we show that Fgf8 morphogen gradients in living zebrafish embryos are established and maintained by two essential factors: fast, free diffusion of single molecules away from the source through extracellular space, and a sink function of the receiving cells, regulated by receptor-mediated endocytosis. Evidence is provided by directly examining single molecules of Fgf8 in living tissue by fluorescence correlation spectroscopy, quantifying their local mobility and concentration with high precision. By changing the degree of uptake of Fgf8 into its target cells, we are able to alter the shape of the Fgf8 gradient. Our results demonstrate that a freely diffusing morphogen can set up concentration gradients in a complex multicellular tissue by a simple source-sink mechanism.
