DEF- and GLO-like proteins may have lost most of their interaction partners during angiosperm evolution
DEF- and GLO-like proteins may have lost most of their interaction partners during angiosperm evolution
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DOI：
10.1093/aob/mcu094
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发表时间：
2014-11-01
期刊：
影响因子：
4.2
通讯作者：
Theissen, Guenter
中科院分区：
文献类型：
--
作者：
Melzer, Rainer;Haerter, Andrea;Theissen, Guenter
DEFICIENS（DEF）-和GLOBOSA（GLO）-样蛋白构成两个姐妹分支的花同源异型转录因子，已经存在于现存被子植物的最近的共同祖先（MRCA）。它们共同确定了开花植物的花瓣和雄蕊的身份。在核心真双子叶植物中，DEF-和GLO-样蛋白在细胞中仅作为彼此的异二聚体起作用。有证据表明，这种专性异源二聚化有助于在进化过程中的核心真双子叶植物的花结构的渠化。目前尚不清楚这种严格的异源二聚化是否是一种古老的特征，可以追溯到现存的显花植物的MRCA，或者它是否是在被子植物的进化过程中进化而来的。杂交分析和电泳迁移率变动分析（EMSA）。酵母双杂交和EMSA数据表明，早期分化被子植物的DEF-和GLO-样蛋白既有同源二聚体，也有异源二聚体。状态重建表明，形成异二聚体复合物的能力已经存在于现存的被子植物的MRCA，这种属性仍然高度保守的被子植物进化。DEF和GLO-like蛋白的同源二聚体也存在于所有现存被子植物的MRCA。DEF样蛋白同源二聚体可能在被子植物进化的早期就丢失了，并且在真双子叶植物和单子叶植物的MRCA中不存在。GLO-like蛋白的同源二聚体可能在进化后期丢失，但很可能不存在于真双子叶植物的MRCA中。DEF和GLO-like蛋白在早期分化的被子植物中相互作用的灵活性可能是这些物种中观察到的高度多样的花形态的原因之一。这些结果加强了这样一个假设，即DEF和GLO样蛋白的相互作用伙伴的数量减少，与DEF-GLO异二聚体仍然是核心真双子叶植物中唯一的DNA结合二聚体，有助于发展的稳健性，渠化的花发育和被子植物的多样化。
DEFICIENS (DEF)- and GLOBOSA (GLO)-like proteins constitute two sister clades of floral homeotic transcription factors that were already present in the most recent common ancestor (MRCA) of extant angiosperms. Together they specify the identity of petals and stamens in flowering plants. In core eudicots, DEF- and GLO-like proteins are functional in the cell only as heterodimers with each other. There is evidence that this obligate heterodimerization contributed to the canalization of the flower structure of core eudicots during evolution. It remains unknown as to whether this strict heterodimerization is an ancient feature that can be traced back to the MRCA of extant flowering plants or if it evolved later during the evolution of the crown group angiosperms.The interactions of DEF- and GLO-like proteins of the early-diverging angiosperms Amborella trichopoda and Nuphar advena and of the magnoliid Liriodendron tulipifera were analysed by employing yeast two-hybrid analysis and electrophoretic mobility shift assay (EMSA). Character-state reconstruction, including data from other species as well, was used to infer the ancestral interaction patterns of DEF- and GLO-like proteins.The yeast two-hybrid and EMSA data suggest that DEF- and GLO-like proteins from early-diverging angiosperms both homo- and heterodimerize. Character-state reconstruction suggests that the ability to form heterodimeric complexes already existed in the MRCA of extant angiosperms and that this property remained highly conserved throughout angiosperm evolution. Homodimerization of DEF- and GLO-like proteins also existed in the MRCA of all extant angiosperms. DEF-like protein homodimerization was probably lost very early in angiosperm evolution and was not present in the MRCA of eudicots and monocots. GLO-like protein homodimerization might have been lost later during evolution, but very probably was not present in the MRCA of eudicots.The flexibility of DEF- and GLO-like protein interactions in early-diverging angiosperms may be one reason for the highly diverse flower morphologies observed in these species. The results strengthen the hypothesis that a reduction in the number of interaction partners of DEF- and GLO-like proteins, with DEF-GLO heterodimers remaining the only DNA-binding dimers in core eudicots, contributed to developmental robustness, canalization of flower development and the diversification of angiosperms.