The irregular xylem3 locus of arabidopsis encodes a cellulose synthase required for secondary cell wall synthesis
The irregular xylem3 locus of arabidopsis encodes a cellulose synthase required for secondary cell wall synthesis
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DOI：
10.1105/tpc.11.5.769
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发表时间：
1999-05-01
期刊：
影响因子：
11.6
通讯作者：
Turner, SR
中科院分区：
文献类型：
--
作者：
Taylor, NG;Scheible, WR;Turner, SR
拟南芥的不规则木质部3(IRX3)突变体在次生细胞壁纤维素沉积方面存在严重缺陷，导致木质部细胞崩溃。IRX3突变已被定位在标记nga106附近的V染色体上臂。与纤维素合酶序列相似的表达序列标签克隆75G11被发现与IRX3紧密连锁，含有与克隆75G11对应的基因的基因组克隆与IRX3突变互补。因此，IRX3基因编码一种纤维素合成酶成分，这是次生细胞壁合成纤维素所特需的。IRX3突变等位基因含有一个终止密码子，该终止密码子使基因产物截短168个氨基酸，表明该等位基因为零。此外，与径向膨大1(Rsw1)植物相比，IRX3植物在非晶质细胞壁组分中β-1，4-连接葡萄糖的积累没有增加。IRX3和RSW1属于拟南芥基因的一个不同的亚组(CSA)，显示出与细菌纤维素合成酶的同源性。
The irregular xylem3 (irx3) mutant of Arabidopsis has a severe deficiency in secondary cell wall cellulose deposition that leads to collapsed xylem cells. The irx3 mutation has been mapped to the top arm of chromosome V near the marker nga106. Expressed sequence tag clone 75G11, which exhibits sequence similarity to cellulose synthase, was found to be tightly linked to irx3, and genomic clones containing the gene corresponding to clone 75G11 complemented the irx3 mutation. Thus, the IRX3 gene encodes a cellulose synthase component that is specifically required for the synthesis of cellulose in the secondary cell wall. The irx3 mutant allele contains a stop codon that truncates the gene product by 168 amino acids, suggesting that this allele is null, Furthermore, in contrast to radial swelling1 (rsw1) plants, irx3 plants show no increase in the accumulation of beta-1,4-linked glucose in the noncrystalline cell wall fraction. IRX3 and RSW1 fall into a distinct subgroup (Csa) of Arabidopsis genes showing homology to bacterial cellulose synthases.