Functional divergence within the APETALA3/PISTILLATA floral homeotic gene lineages
Functional divergence within the APETALA3/PISTILLATA floral homeotic gene lineages
复制标题
DOI：
10.1073/pnas.0631708100
复制
发表时间：
2003-05-27
影响因子：
11.1
通讯作者：
Irish, VF
中科院分区：
文献类型：
--
作者：
Lamb, RS;Irish, VF
同源基因表达模式或编码蛋白功能的变化被认为在新形态的进化中起着重要作用。拟南芥花同源基因aptala3 （AP3）和PISTILLATA （PI）编码含有MAIDS结构域的转录因子，这些转录因子是确定花瓣和雄蕊身份所必需的。我们之前的研究表明，AP3和PI同源物在不同花型结构的被子植物的花被中表达不同，表明表达的变化可能导致形态的改变。我们已经研究了编码基因产物功能的变化可能也在不同花形态的进化中发挥了作用。AP3和PI是同源基因谱系的成员，在蛋白产物的长度上具有广泛的相似性。这些谱系中的基因编码具有特征c端基序的产物，我们发现这些基序对功能特异性至关重要。特别是，AP3的C端足以赋予AP3在异源PI蛋白上的功能。此外，我们还表明，核核核簇中发散型AP3 c -末端结构域的演化与获得指定花被结构的作用有关。这些结果表明，这些序列基序的差异促成了这些花同源基因产物的不同功能的进化。
Changes in homeotic gene expression patterns or in the functions of the encoded proteins are thought to play a prominent role in the evolution of new morphologies. The floral homeotic APETALA3 (AP3) and PISTILLATA (PI) genes encode MAIDS domain-containing transcription factors required to specify petal and stamen identities in Arabidopsis. We have previously shown that perianth expression of AP3 and PI homologs varies in different groups of angiosperms with diverse floral structures, suggesting that changes in expression may contribute to changing morphology. We have investigated the possibility that changes in the functions of the encoded gene products may also have played a role in the evolution of different floral morphologies. AP3 and PI are members of paralogous gene lineages and share extensive similarity along the length of the protein products. Genes within these lineages encode products with characteristic C-terminal motifs that we show are critical for functional specificity. In particular, the C terminus of AP3 is sufficient to confer AP3 functionality on the heterologous PI protein. Furthermore, we have shown that the evolution of the divergent AP3 C-terminal domain in the core eudicots is correlated with the acquisition of a role in specifying perianth structures. These results suggest that divergence in these sequence motifs has contributed to the evolution of distinct functions for these floral homeotic gene products.