Itoh Nobuyuki, Ornitz David M
Department of Genetic Biochemistry, Kyoto University Graduate School of Pharmaceutical Sciences, Yoshida-Shimoadachi, Sakyo, Kyoto 606-8501, Japan.
Trends Genet. 2004 Nov;20(11):563-9. doi: 10.1016/j.tig.2004.08.007.
Fibroblast growth factors (Fgfs) and Fgf receptors (Fgfrs) comprise a signaling system that is conserved throughout metazoan evolution. Twenty-two Fgfs and four Fgfrs have been identified in humans and mice. During evolution, the Fgf family appears to have expanded in two phases. In the first phase, during early metazoan evolution, Fgfs expanded from two or three to six genes by gene duplication. In the second phase, during the evolution of early vertebrates, the Fgf family expanded by two large-scale gen(om)e duplications. By contrast, the Fgfr family has expanded only in the second phase. However, the acquisition of alternative splicing by Fgfrs has increased their functional diversity. The mechanisms that regulate alternative splicing have been conserved since the divergences of echinoderms and vertebrates. The expansion of the Fgf and Fgfr gene families has enabled this signaling system to acquire functional diversity and, therefore, an almost ubiquitous involvement in developmental and physiological processes.
成纤维细胞生长因子（Fgfs）和成纤维细胞生长因子受体（Fgfrs）构成了一个在整个后生动物进化过程中保守的信号系统。在人类和小鼠中已鉴定出22种Fgfs和4种Fgfrs。在进化过程中，Fgf家族似乎经历了两个阶段的扩张。在第一阶段，在后生动物早期进化过程中，Fgfs通过基因复制从两三个基因扩展到六个基因。在第二阶段，在早期脊椎动物的进化过程中，Fgf家族通过两次大规模的基因组复制而扩张。相比之下，Fgfr家族仅在第二阶段有所扩张。然而，Fgfrs通过选择性剪接增加了它们的功能多样性。自棘皮动物和脊椎动物分化以来，调节选择性剪接的机制一直保守。Fgf和Fgfr基因家族的扩张使这个信号系统能够获得功能多样性，因此几乎普遍参与发育和生理过程。
