Boudet N, Aubourg S, Toffano-Nioche C, Kreis M, Lecharny A
Institut de Biotechnologie des Plantes, Unité Mixte de Recherche-Centre National Recherche Scientifique 8618, Université de Paris-Sud, Bât. 630, F-91405 Orsay Cedex, France.
Genome Res. 2001 Dec;11(12):2101-14. doi: 10.1101/gr.200801.
The DEAD box RNA helicase (RH) proteins are homologs involved in diverse cellular functions in all of the organisms from prokaryotes to eukaryotes. Nevertheless, there is a lack of conservation in the splicing pattern in the 53 Arabidopsis thaliana (AtRHs), the 32 Caenorhabditis elegans (CeRHs) and the 29 Drosophila melanogaster (DmRHs) genes. Of the 153 different observed intron positions, 4 are conserved between AtRHs, CeRHs, and DmRHs, and one position is also found in RHs from yeast and human. Of the 27 different AtRH structures with introns, 20 have at least one predicted ancient intron in the regions coding for the catalytic domain. In all of the organisms examined, we found at least one gene with most of its intron predicted to be ancient. In A. thaliana, the large diversity in RH structures suggests that duplications of the ancestral RH were followed by a high number of intron deletions and additions. The very high bias toward phase 0 introns is in favor of intron addition, preferentially in phase 0. Results from this comparative study of the same gene family in a plant and in two animals are discussed in terms of the general mechanisms of gene family evolution.
DEAD盒RNA解旋酶（RH）蛋白是原核生物到真核生物中参与多种细胞功能的同源物。然而，拟南芥（AtRHs）的53个基因、秀丽隐杆线虫（CeRHs）的32个基因和黑腹果蝇（DmRHs）的29个基因在剪接模式上缺乏保守性。在观察到的153个不同内含子位置中，有4个在AtRHs、CeRHs和DmRHs之间保守，还有一个位置在酵母和人类的RH中也有发现。在27个具有内含子的不同AtRH结构中，有20个在编码催化结构域的区域至少有一个预测的古老内含子。在所有检测的生物中，我们发现至少有一个基因的大部分内含子被预测为古老内含子。在拟南芥中，RH结构的巨大多样性表明祖先RH的复制之后伴随着大量内含子的缺失和添加。对0相位内含子的极高偏向性有利于内含子添加，优先在0相位。本文从基因家族进化的一般机制方面讨论了对植物和两种动物中同一基因家族的比较研究结果。
