The thanatos mutation in Arabidopsis thaliana cellulose synthase 3 (AtCesA3) has a dominant-negative effect on cellulose synthesis and plant growth
The thanatos mutation in Arabidopsis thaliana cellulose synthase 3 (AtCesA3) has a dominant-negative effect on cellulose synthesis and plant growth
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DOI：
10.1111/j.1469-8137.2009.02960.x
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发表时间：
2009-01-01
期刊：
影响因子：
9.4
通讯作者：
Hatzopoulos, Polydefkis
中科院分区：
文献类型：
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作者：
Daras, Gerasimos;Rigas, Stamatis;Hatzopoulos, Polydefkis
对编码纤维素合酶 (CesAs) 的植物基因突变体的遗传功能分析表明，纤维素沉积需要多种 CesA 蛋白的活性。在这里，遗传筛选导致鉴定出 Thanatos (han)，这是一种拟南芥的半显性突变体，其幼苗生长受损。than 的纯合幼苗可以发芽并生长，但不能存活。与其他 CesA 突变体相比，杂合植物矮化并表现出径向肿胀的根表型。杂合植物中的纤维素含量减少约五分之一，纯合植物中的纤维素含量减少约五分之二，显示出基因剂量依赖性。基于图谱的克隆揭示了 AtCesA3 基因催化结构域中的氨基酸取代 (P578S)，表明该残基在纤维素合酶复合物的结构和功能中发挥着关键作用。对保守脯氨酸残基侧翼的 AtCesA3 亚结构域的从头开始分析预测，丝氨酸的氨基酸取代会改变催化结构域中的蛋白质二级结构。 AtCesA3突变基因在野生型拟南芥植物中的基因剂量依赖性表达导致显性失活表型。我们提出，将错误折叠的CesA3亚基掺入纤维素合酶复合物中可能会阻止或阻止功能性莲座复合物的形成。
Genetic functional analyses of mutants in plant genes encoding cellulose synthases (CesAs) have suggested that cellulose deposition requires the activity of multiple CesA proteins.Here, a genetic screen has led to the identification of thanatos (han), a semidominant mutant of Arabidopsis thaliana with impaired growth of seedlings.Homozygous seedlings of than germinate and grow but do not survive. In contrast to other CesA mutants, heterozygous plants are dwarfed and display a radially swollen root phenotype. Cellulose content is reduced by approximately one-fifth in heterozygous and by two-fifths in homozygous plants, showing gene-dosage dependence. Map-based cloning revealed an amino acid substitution (P578S) in the catalytic domain of the AtCesA3 gene, indicating a critical role for this residue in the structure and function of the cellulose synthase complex. Ab initio analysis of the AtCesA3 subdomain flanking the conserved proline residue predicted that the amino acid substitution to serine alters protein secondary structure in the catalytic domain. Gene dosage-dependent expression of the AtCesA3 mutant gene in wild-type A. thaliana plants resulted in a than dominant-negative phenotype.We propose that the incorporation of a mis-folded CesA3 subunit into the cellulose synthase complex may stall or prevent the formation of functional rosette complexes.