Two Hydroxyproline Galactosyltransferases, GALT5 and GALT2, Function in Arabinogalactan-Protein Glycosylation, Growth and Development in Arabidopsis.
Two Hydroxyproline Galactosyltransferases, GALT5 and GALT2, Function in Arabinogalactan-Protein Glycosylation, Growth and Development in Arabidopsis.
复制标题
DOI：
10.1371/journal.pone.0125624
复制
发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Showalter AM
中科院分区：
文献类型：
--
作者：
Basu D;Wang W;Ma S;DeBrosse T;Poirier E;Emch K;Soukup E;Tian L;Showalter AM
羟脯氨酸-O-半乳糖基转移酶（GALT）启动阿拉伯半乳聚糖蛋白（AGP）的O-糖基化。我们以前的特点GALT 2（At 4g 21060），现在报告的功能特性GALT 5（At 1g 74800）。使用毕赤酵母中的异源表达和体外GALT测定鉴定GALT 5。产物表征显示GALT 5特异性地将半乳糖添加到AGP蛋白骨架中的羟脯氨酸。通过单突变体和双突变体的表型分析，阐明了GALT 2和GALT 5的功能。与野生型相比，等位基因galt 5和galt 2突变体，特别是galt 2 galt 5双突变体，表现出较低的GALT活性和β-Yariv沉淀的AGP减少。突变体植株表现出多效性的生长发育表型（根毛生长、根伸长、花粉管生长、开花时间、叶片发育、角果长度和花序生长的缺陷），其中以双突变体最为严重。条件突变体表现为对盐敏感的根生长和根尖膨大，以及对β-Yariv试剂的响应降低了对花粉管生长和根生长的抑制。这些突变体也是AGP、SOS 5和两种细胞壁受体样激酶FEI 1和FEI 2的表型突变体，它们存在于遗传信号传导途径中。总之，GALT 5和GALT 2作为控制AGP 0-糖基化的冗余GALT起作用，这对于正常生长和发育是必需的。
Hydroxyproline-O-galactosyltransferase (GALT) initiates O-glycosylation of arabinogalactan-proteins (AGPs). We previously characterized GALT2 (At4g21060), and now report on functional characterization of GALT5 (At1g74800). GALT5 was identified using heterologous expression in Pichia and an in vitro GALT assay. Product characterization showed GALT5 specifically adds galactose to hydroxyproline in AGP protein backbones. Functions of GALT2 and GALT5 were elucidated by phenotypic analysis of single and double mutant plants. Allelic galt5 and galt2 mutants, and particularly galt2 galt5 double mutants, demonstrated lower GALT activities and reductions in β-Yariv-precipitated AGPs compared to wild type. Mutant plants showed pleiotropic growth and development phenotypes (defects in root hair growth, root elongation, pollen tube growth, flowering time, leaf development, silique length, and inflorescence growth), which were most severe in the double mutants. Conditional mutant phenotypes were also observed, including salt-hypersensitive root growth and root tip swelling as well as reduced inhibition of pollen tube growth and root growth in response to β-Yariv reagent. These mutants also phenocopy mutants for an AGP, SOS5, and two cell wall receptor-like kinases, FEI1 and FEI2, which exist in a genetic signaling pathway. In summary, GALT5 and GALT2 function as redundant GALTs that control AGP O-glycosylation, which is essential for normal growth and development.
登录
查看更多内容
影响因子：
7.4
作者：
Dardelle, Flavien;Lehner, Arnaud;Mollet, Jean-Claude
通讯作者：
Mollet, Jean-Claude
DOI：
10.1073/pnas.0800237105
发表时间：
2008-04-15
影响因子：
11.1
作者：
Kang, Jae Sook;Frank, Julia;Koiwa, Hisashi
通讯作者：
Koiwa, Hisashi
影响因子：
7.4
作者：
GARDINER, M;CHRISPEELS, MJ
通讯作者：
CHRISPEELS, MJ
影响因子：
11.6
作者：
Cheung, AY;Chen, CYH;Wu, HM
通讯作者：
Wu, HM
影响因子：
7.2
作者：
Baumberger, N;Steiner, M;Ringli, C
通讯作者：
Ringli, C