生物谷報(bào)道：昆明動(dòng)物研究所遺傳資源與進(jìn)化國(guó)家重點(diǎn)實(shí)驗(yàn)室(籌)何靜等研究了脊椎動(dòng)物motilin/ghrelin荷爾蒙及其受體基因家族的進(jìn)化歷史,，揭示了ghrelin/GHSR信號(hào)通路系統(tǒng)的保守性，以及新的motilin/MLNR信號(hào)通路系統(tǒng)的演化形成機(jī)制,。由此他們提出了分子相互作用網(wǎng)絡(luò)系統(tǒng)進(jìn)化形成的一種模式：新功能關(guān)系形成之前,，通常存在基因共享，即一種分子參與到多個(gè)過(guò)程,、多種分子間相互作用,。基因重復(fù)產(chǎn)生了新的組分,，其中一個(gè)被征募與已經(jīng)存在的分子形成新的分子間相互作用,，從而分化形成新的網(wǎng)絡(luò)關(guān)系；另一個(gè)則維持原有的網(wǎng)絡(luò)關(guān)系,，并產(chǎn)生了功能的?；＿@項(xiàng)工作對(duì)于理解復(fù)雜的分子相互作用網(wǎng)絡(luò)系統(tǒng)的形成機(jī)制提供了新的線索,。該成果是在973項(xiàng)目和國(guó)家自然科學(xué)基金資助下取得的,，于近期發(fā)表在國(guó)際著名刊物Molecular Biology and Evolution網(wǎng)絡(luò)上(doi:10.1093/molbev/msm161)。（援引 昆明動(dòng)物研究所）
原始出處:
MBE Advance Access published online on August 16, 2007
Molecular Biology and Evolution, doi:10.1093/molbev/msm161
Insights into the Evolution of the Motilin/Ghrelin-Associated Family and Their Receptors
Jing He1,2, David M. Irwin3 and Ya-ping Zhang1,4
1 State Key Laboratory of Cellular and Molecular Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
2 The Graduate School, Chinese Academy of Sciences, Beijing 100049, China
3 Departments of Laboratory Medicine and Pathobiology and the Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
4 Laboratory for Conservation and Utilization of Bioresource, Yunnan University, Kunming 650091, China
Corresponding author: Prof. Dr. Ya-Ping Zhang, Laboratory of Cellular and Molecular Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, 32 Jiaochang Donglu Kunming, Yunnan, 650223 P. R China PHONE:(+86) 871-519 0761; FAX:(+86) 871-519 5430, E-mail: [email protected] or [email protected]
Received for publication April 16, 2007. Revision received July 16, 2007. Accepted for publication July 21, 2007.
A hormone-receptor pair is usually thought of as a biological lock and key. Building a lock-and-key system seems to require at least the evolution of two traits to happen simultaneously, an event that appears highly unlikely. Thus it is not apparent how selection can drive the evolution of a part of the system as a whole. Here we demonstrate how evolutionary processes assemble complex systems that depend on specific interactions among the parts. Based on phylogenetic analyses and molecular inferences, we show that, MLN and GHRL descended from a common ancestor, and that gene duplication occurred shortly after the divergence of amphibians and amniotes. The evolutionary history of the receptors differs from their cognate ligands. GPR39 diverged first, and an ancestral GHSR-like receptor gave rise to a fish specific clade A, GHSR and MLNR by successive gene duplication that occurred before the divergence of tetrapods and fish. The ghrelin/GHSR system has been maintained and functionally conserved from fish to mammals, while motilin-MLNR specificity only evolved, as the result of ligand-receptor coevolution, after the hormone gene duplicated. A model for the evolution of novelties in tightly integrated biological systems is proposed under which a period of gene sharing ordinarily precedes the evolution of distinct functionality. Novel interactions emerge when a newly generated molecule is recruited as a binding partner of an old molecule, which was previously constrained by selection for a different function. Gene duplication then allows each daughter gene to specialize for subfunctions of the ancestral gene.
Key Words: ghrelin • motilin • obestatin • gene family • receptor • coevolution • gene interaction
