The Arabidopsis thaliana genome contains at least 29 active genes encoding SET domain proteins that can be assigned to four evolutionarily conserved classes
The Arabidopsis thaliana genome contains at least 29 active genes encoding SET domain proteins that can be assigned to four evolutionarily conserved classes
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DOI：
10.1093/nar/29.21.4319
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发表时间：
2001-11-01
影响因子：
14.9
通讯作者：
Aalen, RB
中科院分区：
文献类型：
--
作者：
Baumbusch, LO;Thorstensen, T;Aalen, RB
SET结构域是存在于染色体蛋白中的保守氨基酸基序，其在基因表达的表观遗传控制中起作用。这些蛋白质可分为四类，以它们的果蝇成员E（Z）、TRX、ASH 1和SU（VAR）3-9为代表。所有四类的同源物都已在酵母和哺乳动物中鉴定，但在植物中没有。拟南芥基因组的BLASTP筛选鉴定了37个基因：3个E（z）同源物，5个trx同源物，4个ash 1同源物和15个与Su（var）3-9相似的基因。其中7个基因与trx相关，3个与ash 1相关。之前只描述了四个基因。我们的分类是基于SET结构域，半胱氨酸丰富的区域和额外的保守结构域，包括一个新的YGD结构域的特征。RT-PCR分析，cDNA克隆和匹配的EST显示，至少有29个基因在不同的组织中有活性。大量的SET结构域基因，可能参与在植物发育过程中的基因活性的表观遗传控制，可以部分地解释在拟南芥中广泛的基因组重复。此外，在8个SU（VAR）3-9类基因的编码区中缺少内含子表明通过反转录转座进化新基因。推定的核定位信号和AT钩在许多蛋白质的鉴定支持预期的核定位，这是证明选定的蛋白质。
SET domains are conserved amino acid motifs present in chromosomal proteins that function in epigenetic control of gene expression. These proteins can be divided into four classes as typified by their Drosophila members E(Z), TRX, ASH1 and SU(VAR)3-9. Homologs of all four classes have been identified in yeast and mammals, but not in plants. A BLASTP screening of the Arabidopsis genome identified 37 genes: three E(z) homologs, five trx homologs, four ash1 homologs and 15 genes similar to Su(var)3-9. Seven genes were assigned as trx-related and three as ash1-related. Only four genes have been described previously. Our classification is based on the characteristics of the SET domains, cysteine-rich regions and additional conserved domains, including a novel YGD domain. RT-PCR analysis, cDNA cloning and matching ESTs show that at least 29 of the genes are active in diverse tissues. The high number of SET domain genes, possibly involved in epigenetic control of gene activity during plant development, can partly be explained by extensive genome duplication in Arabidopsis. Additionally, the lack of introns in the coding region of eight SU(VAR)3-9 class genes indicates evolution of new genes by retrotransposition. The identification of putative nuclear localization signals and AT-hooks in many of the proteins supports an anticipated nuclear localization, which was demonstrated for selected proteins.