Arabidopsis genes IRREGULAR XYLEM (IRX15) and IRX15L encode DUF579-containing proteins that are essential for normal xylan deposition in the secondary cell wall
Arabidopsis genes IRREGULAR XYLEM (IRX15) and IRX15L encode DUF579-containing proteins that are essential for normal xylan deposition in the secondary cell wall
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DOI：
10.1111/j.1365-313x.2011.04501.x
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发表时间：
2011-05-01
期刊：
影响因子：
7.2
通讯作者：
Turner, Simon
中科院分区：
文献类型：
--
作者：
Brown, David;Wightman, Raymond;Turner, Simon
拟南芥基因组中有10个基因包含一个在Pfam数据库中被描述为未知功能域579(DUF579)的结构域。虽然DUF579在真核生物中广泛分布，但没有直接的实验证据来确定它的功能。在拟南芥DUF579家族的10个成员中，有5个与次生细胞壁形成的标记基因共表达。在DUF579家族中两个密切相关的成员被T-DNA插入干扰的植物中，由于木聚糖含量的减少，次生细胞壁中的木糖含量较少，并且表现出轻微扭曲的木质部导管。因此，我们将这些基因命名为不规则木质部15(IRX15)和IRX15L。这些突变植物表现出许多先前描述的木聚糖合成突变体的特征，例如用甲基葡萄糖醛酸侧链替换葡萄糖醛酸侧链。相比之下，木聚糖免疫染色和透射电子显微镜(TEM)显示，与野生型或其他木聚糖突变体相比，这些irx15 irx15双突变体的细胞壁结构紊乱，细胞壁消化试验中释放的糖分显著增加。此外，使用荧光融合蛋白的定位研究既标记了高尔基体，也标记了一个未知的细胞内隔室。这些数据与定义了一类新的木聚糖生物合成基因的irx15和irx15l是一致的。讨论了这些基因在木聚糖生物合成和沉积过程中的作用。
There are 10 genes in the Arabidopsis genome that contain a domain described in the Pfam database as domain of unknown function 579 (DUF579). Although DUF579 is widely distributed in eukaryotic species, there is no direct experimental evidence to assign a function to it. Five of the 10 Arabidopsis DUF579 family members are co-expressed with marker genes for secondary cell wall formation. Plants in which two closely related members of the DUF579 family have been disrupted by T-DNA insertions contain less xylose in the secondary cell wall as a result of decreased xylan content, and exhibit mildly distorted xylem vessels. Consequently we have named these genes IRREGULAR XYLEM 15 (IRX15) and IRX15L. These mutant plants exhibit many features of previously described xylan synthesis mutants, such as the replacement of glucuronic acid side chains with methylglucuronic acid side chains. By contrast, immunostaining of xylan and transmission electron microscopy (TEM) reveals that the walls of these irx15 irx15l double mutants are disorganized, compared with the wild type or other previously described xylan mutants, and exhibit dramatic increases in the quantity of sugar released in cell wall digestibility assays. Furthermore, localization studies using fluorescent fusion proteins label both the Golgi and also an unknown intracellular compartment. These data are consistent with irx15 and irx15l defining a new class of genes involved in xylan biosynthesis. How these genes function during xylan biosynthesis and deposition is discussed.