Irish V F, Yamamoto Y T
Department of Biology, Osborn Memorial Laboratory, Yale University, New Haven, Connecticut 06520-8104, USA.
Plant Cell. 1995 Oct;7(10):1635-44. doi: 10.1105/tpc.7.10.1635.
Several homeotic genes controlling floral development have been isolated in both Antirrhinum and Arabidopsis. Based on the similarities in sequence and in the phenotypes elicited by mutations in some of these genes, it has been proposed that the regulatory hierarchy controlling floral development is comparable in these two species. We have performed a direct experimental test of this hypothesis by introducing a chimeric Antirrhinum Deficiens (DefA)/Arabidopsis APETALA3 (AP3) gene, under the control of the Arabidopsis AP3 promoter, into Arabidopsis. We demonstrated that this transgene is sufficient to partially complement severe mutations at the AP3 locus. In combination with a weak ap3 mutation, this transgene is capable of completely rescuing the mutant phenotype to a fully functional wild-type flower. These observations indicate that despite differences in DNA sequence and expression, DefA coding sequences can compensate for the loss of AP3 gene function. We discuss the implications of these results for the evolution of homeotic gene function in flowering plants.
在金鱼草和拟南芥中都分离出了几个控制花发育的同源异型基因。基于这些基因中一些基因的序列相似性以及突变引发的表型相似性，有人提出控制花发育的调控层级在这两个物种中具有可比性。我们通过将一个在拟南芥AP3启动子控制下的嵌合金鱼草Deficiens（DefA）/拟南芥APETALA3（AP3）基因导入拟南芥，对这一假说进行了直接的实验验证。我们证明，这个转基因足以部分互补AP3位点的严重突变。与一个弱的ap3突变相结合时，这个转基因能够将突变表型完全拯救为功能完全正常的野生型花。这些观察结果表明，尽管DNA序列和表达存在差异，但DefA编码序列能够补偿AP3基因功能的丧失。我们讨论了这些结果对开花植物中同源异型基因功能进化的意义。
