Functional Conservation of MIKC*-Type MADS Box Genes in Arabidopsis and Rice Pollen Maturation
Functional Conservation of MIKC*-Type MADS Box Genes in Arabidopsis and Rice Pollen Maturation
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MIKC* 型 MADS Box 基因在拟南芥和水稻花粉成熟中的功能保守
DOI：
10.1105/tpc.113.110049
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发表时间：
2013-04-01
期刊：
影响因子：
11.6
通讯作者：
Meng, Zheng
中科院分区：
文献类型：
--
作者：
Liu, Yuan;Cui, Shaojie;Meng, Zheng
MADS干预角蛋白样蛋白和c端（MIKC）型MADS盒子基因有两组，MIKCC型和MIKC*型。在种子植物中，MIKCC型具有相当大的多样性，但MIKC*型只有两个亚群，P-和s -枝，在配子体中保守表达。为了研究MIKC*型基因的功能保守性，我们对水稻（Oryza sativa）的三种MIKC*型基因进行了鉴定。这三个基因都在花粉发育后期特异性表达。s支系MADS62和MADS63的单敲除和敲除系均未表现出突变表型，但两个s支系均受到影响的系在花粉成熟和萌发方面表现出严重缺陷，水稻中唯一的p支系MADS68的敲除系也是如此。水稻MIKC*型蛋白仅与来自其他亚支系的伙伴形成强的异二聚体复合物；这些复合物在体外特异性结合n10型c - a -rich- g -box，并通过结合n10型启动子基序调节下游基因表达。水稻MIKC*基因的功能冗余度远低于拟南芥MIKC*基因。然而，我们的数据表明，自大约1.5亿年前单子房和双子房分化以来，异二聚体MIKC*型蛋白复合物在花粉发育中的功能一直保持不变。
There are two groups of MADS intervening keratin-like and C-terminal (MIKC)-type MADS box genes, MIKCC type and MIKC* type. In seed plants, the MIKCC type shows considerable diversity, but the MIKC* type has only two subgroups, P- and S-clade, which show conserved expression in the gametophyte. To examine the functional conservation of MIKC*-type genes, we characterized all three rice (Oryza sativa) MIKC*-type genes. All three genes are specifically expressed late in pollen development. The single knockdown or knockout lines, respectively, of the S-clade MADS62 and MADS63 did not show a mutant phenotype, but lines in which both S-clade genes were affected showed severe defects in pollen maturation and germination, as did knockdown lines of MADS68, the only P-clade gene in rice. The rice MIKC*-type proteins form strong heterodimeric complexes solely with partners from the other subclade; these complexes specifically bind to N10-type C-A-rich-G-boxes in vitro and regulate downstream gene expression by binding to N10-type promoter motifs. The rice MIKC* genes have a much lower degree of functional redundancy than the Arabidopsis thaliana MIKC* genes. Nevertheless, our data indicate that the function of heterodimeric MIKC*-type protein complexes in pollen development has been conserved since the divergence of monocots and eudicots, roughly 150 million years ago.