Persson Staffan, Paredez Alexander, Carroll Andrew, Palsdottir Hildur, Doblin Monika, Poindexter Patricia, Khitrov Natalie, Auer Manfred, Somerville Chris R
Department of Plant Biology, Carnegie Institution, Stanford, CA 94305, USA.
Proc Natl Acad Sci U S A. 2007 Sep 25;104(39):15566-71. doi: 10.1073/pnas.0706592104. Epub 2007 Sep 18.
In higher plants, cellulose is synthesized at the plasma membrane by the cellulose synthase (CESA) complex. The catalytic core of the complex is believed to be composed of three types of CESA subunits. Indirect evidence suggests that the complex associated with primary wall cellulose deposition consists of CESA1, -3, and -6 in Arabidopsis thaliana. However, phenotypes associated with mutations in two of these genes, CESA1 and -6, suggest unequal contribution by the different CESAs to overall enzymatic activity of the complex. We present evidence that the primary complex requires three unique types of components, CESA1-, CESA3-, and CESA6-related, for activity. Removal of any of these components results in gametophytic lethality due to pollen defects, demonstrating that primary-wall cellulose synthesis is necessary for pollen development. We also show that the CESA6-related CESAs are partially functionally redundant.
在高等植物中，纤维素由纤维素合酶（CESA）复合体在质膜上合成。该复合体的催化核心被认为由三种类型的CESA亚基组成。间接证据表明，拟南芥中与初生壁纤维素沉积相关的复合体由CESA1、CESA3和CESA6组成。然而，与其中两个基因CESA1和CESA6突变相关的表型表明，不同的CESA对复合体整体酶活性的贡献不均等。我们提供的证据表明，初级复合体需要三种独特类型的组分，即CESA1相关、CESA3相关和CESA6相关的组分才能发挥活性。去除这些组分中的任何一种都会因花粉缺陷导致配子体致死，这表明初生壁纤维素合成对于花粉发育是必需的。我们还表明，CESA6相关的CESA在功能上存在部分冗余。
