Di Giacomo Elisabetta, Sestili Francesco, Iannelli Maria Adelaide, Testone Giulio, Mariotti Domenico, Frugis Giovanna
Institute of Biology and Agricultural Biotechnology, Operative Unit of Rome, Consiglio Nazionale delle Ricerche, Via Salaria Km. 29,300, Monterotondo Scalo, Roma, Italy.
Plant Mol Biol. 2008 May;67(1-2):135-50. doi: 10.1007/s11103-008-9307-7. Epub 2008 Feb 15.
We isolated three class I and three class II KNOX genes in Medicago truncatula. The predicted amino acid sequences suggested a possible orthology to the Arabidopsis homeodomain proteins STM, KNAT1/BP, KNAT3 and KNAT7 that was confirmed by phylogenetic and conserved structural domain analyses. Moreover, the STM-like MtKNOX1 and MtKNOX6 proteins were shown to retain the capability to interact with the Arabidopsis BELL protein partners of STM and KNAT1/BP. Amino acid residues that characterize the different classes of KNOX proteins were identified. Gene expression studies revealed organ-specificity, possible cytokinin-dependent transcriptional activation of two MtKNOXs and expression of one STM-like and a BP/KNAT1-like MtKNOX in roots. Interestingly, mRNA localization studies carried out on class I MtKNOX genes revealed important differences with previously characterised legume KNOXs. M. truncatula transcripts were not down-regulated in leaf primordia and early stages of leaf development, features shared with the more distant compound-leaved species Solanum lycopersicum.
我们在蒺藜苜蓿中分离出了三个I类和三个II类KNOX基因。预测的氨基酸序列表明它们可能与拟南芥同源异型结构域蛋白STM、KNAT1/BP、KNAT3和KNAT7存在直系同源关系，这一点通过系统发育分析和保守结构域分析得到了证实。此外，类似STM的MtKNOX1和MtKNOX6蛋白被证明保留了与拟南芥中STM和KNAT1/BP的BELL蛋白伙伴相互作用的能力。鉴定出了表征不同类KNOX蛋白的氨基酸残基。基因表达研究揭示了器官特异性、两种MtKNOX可能的细胞分裂素依赖性转录激活以及一种类似STM和一种类似BP/KNAT1的MtKNOX在根中的表达。有趣的是，对I类MtKNOX基因进行的mRNA定位研究揭示了与先前表征的豆科KNOX基因的重要差异。蒺藜苜蓿转录本在叶原基和叶片发育早期并未下调，这是与更远缘的复叶物种番茄共有的特征。
