De Bodt Stefanie, Raes Jeroen, Florquin Kobe, Rombauts Stephane, Rouzé Pierre, Theissen Günter, Van de Peer Yves
Department of Plant Systems Biology, Flanders Interuniversity Institute for Biotechnology, Ghent University, K.L Ledeganckstraat 35, Belgium.
J Mol Evol. 2003 May;56(5):573-86. doi: 10.1007/s00239-002-2426-x.
The type I MADS-box genes constitute a largely unexplored subfamily of the extensively studied MADS-box gene family, well known for its role in flower development. Genes of the type I MADS-box subfamily possess the characteristic MADS box but are distinguished from type II MADS-box genes by the absence of the keratin-like box. In this in silico study, we have structurally annotated all 47 members of the type I MADS-box gene family in Arabidopsis thaliana and exerted a thorough analysis of the C-terminal regions of the translated proteins. On the basis of conserved motifs in the C-terminal region, we could classify the gene family into three main groups, two of which could be further subdivided. Phylogenetic trees were inferred to study the evolutionary relationships within this large MADS-box gene subfamily. These suggest for plant type I genes a dynamic of evolution that is significantly different from the mode of both animal type I (SRF) and plant type II (MIKC-type) gene phylogeny. The presence of conserved motifs in the majority of these genes, the identification of Oryza sativa MADS-box type I homologues, and the detection of expressed sequence tags for Arabidopsis thaliana and other plant type I genes suggest that these genes are indeed of functional importance to plants. It is therefore even more intriguing that, from an experimental point of view, almost nothing is known about the function of these MADS-box type I genes.
I型MADS-box基因构成了MADS-box基因家族中一个很大程度上未被探索的亚家族，该基因家族因在花发育中的作用而广为人知。I型MADS-box亚家族的基因拥有典型的MADS框，但与II型MADS-box基因的区别在于缺乏类角蛋白框。在这项计算机模拟研究中，我们对拟南芥I型MADS-box基因家族的所有47个成员进行了结构注释，并对翻译后蛋白质的C端区域进行了深入分析。基于C端区域的保守基序，我们可以将该基因家族分为三个主要组，其中两组可以进一步细分。通过推断系统发育树来研究这个庞大的MADS-box基因亚家族内部的进化关系。这些结果表明，植物I型基因的进化动态与动物I型（SRF）和植物II型（MIKC型）基因系统发育模式显著不同。这些基因中大多数存在保守基序、水稻I型MADS-box同源物的鉴定以及拟南芥和其他植物I型基因表达序列标签的检测表明，这些基因对植物确实具有功能重要性。因此，从实验角度来看，几乎对这些I型MADS-box基因的功能一无所知，这就更令人好奇了。
