Duplication and diversification in the APETALA1/FRUITFULL floral homeotic gene lineage: implications for the evolution of floral development.
Duplication and diversification in the APETALA1/FRUITFULL floral homeotic gene lineage: implications for the evolution of floral development.
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作者：
A. Litt;V. Irish
被子植物MADS-box基因的系统发育分析表明，该基因家族经历了多次重复事件，随后出现序列分歧。为了确定这些事件发生的时间，并了解特定MADS盒基因谱系的关系，我们已经确定了APETALA 1/FRUITFULL样MADS盒基因从各种被子植物物种。我们的系统发育分析表明，在核心真双子叶植物，euAP 1（包括拟南芥APETALA 1和金鱼草SQUAMOSA）和euFUL（包括拟南芥FRUITFULL）的两个基因分支。非核心真双子叶植物物种仅具有与euFUL基因相似的序列（FUL样）。预测的蛋白产物的euFUL和FUL样基因共享一个保守的C-末端基序。相比之下，预测产品的euAP 1基因进化枝的成员含有不同的C末端，包括酸性转录激活结构域和法尼基化信号。序列分析表明，euAP 1氨基酸基序可能已经出现了从euFUL/FUL样基序通过翻译移码。euAP 1基因进化枝包括花发育的关键调节因子，其与花被身份的规范有关。然而，euAP 1基因的存在下，只有在核心真双子叶植物表明，可能已经发生了变化的花发育机制，与固定的花结构中看到这个分支。
Phylogenetic analyses of angiosperm MADS-box genes suggest that this gene family has undergone multiple duplication events followed by sequence divergence. To determine when such events have taken place and to understand the relationships of particular MADS-box gene lineages, we have identified APETALA1/FRUITFULL-like MADS-box genes from a variety of angiosperm species. Our phylogenetic analyses show two gene clades within the core eudicots, euAP1 (including Arabidopsis APETALA1 and Antirrhinum SQUAMOSA) and euFUL (including Arabidopsis FRUITFULL). Non-core eudicot species have only sequences similar to euFUL genes (FUL-like). The predicted protein products of euFUL and FUL-like genes share a conserved C-terminal motif. In contrast, predicted products of members of the euAP1 gene clade contain a different C terminus that includes an acidic transcription activation domain and a farnesylation signal. Sequence analyses indicate that the euAP1 amino acid motifs may have arisen via a translational frameshift from the euFUL/FUL-like motif. The euAP1 gene clade includes key regulators of floral development that have been implicated in the specification of perianth identity. However, the presence of euAP1 genes only in core eudicots suggests that there may have been changes in mechanisms of floral development that are correlated with the fixation of floral structure seen in this clade.