Ndamukong Ivan, Chetram Anand, Saleh Abdelaty, Avramova Zoya
UNL Lincoln, NE 68588-0118, USA.
Plant J. 2009 May;58(4):541-53. doi: 10.1111/j.1365-313X.2009.03798.x. Epub 2009 Jan 19.
The plant cell wall is a dynamic structure playing important roles in the control of plant cell growth and differentiation. These processes involve global reprogramming of the genome driven by dynamic changes in chromatin structure. The chromatin modifier ARABIDOPSIS HOMOLOG OF TRITHORAX (ATX1) methylates lysine residue 4 on histone H3 (H3K4me), acting as an epigenetic mark on associated genes. The remarkable overrepresentation in the ATX1-regulated gene fraction of genes encoding plasma membrane and cell wall-remodeling activities suggested a link between two separate factors affecting growth, development and adaptation in Arabidopsis: the wall-modifying activities regulating cell extension, growth and fate, and the epigenetic mechanisms regulating chromatin structure and gene expression. A co-regulated fraction of specific wall-modifying proteins suggests that they may function together. Here, we study the ATX1-dependent expression of the gene encoding the wall-loosening factor XTH33 as a test case for development- and tissue-specific effects displayed by the chromatin modifier. In addition, we show that XTH33 is, most likely, an integral plasma membrane protein. A putative transmembrane domain is conserved in some, but not all, XTH family members, suggesting that they may be differently positioned when functioning as wall modifiers.
植物细胞壁是一种动态结构，在控制植物细胞生长和分化中发挥着重要作用。这些过程涉及由染色质结构动态变化驱动的基因组全局重编程。染色质修饰因子拟南芥三体同源物（ATX1）使组蛋白H3上的赖氨酸残基4（H3K4me）甲基化，作为相关基因上的一种表观遗传标记。在编码质膜和细胞壁重塑活性的基因的ATX1调控基因部分中显著过度富集，这表明影响拟南芥生长、发育和适应性的两个独立因素之间存在联系：调节细胞伸展、生长和命运的细胞壁修饰活性，以及调节染色质结构和基因表达的表观遗传机制。特定细胞壁修饰蛋白的共同调控部分表明它们可能共同发挥作用。在这里，我们研究编码细胞壁松弛因子XTH33的基因的ATX1依赖性表达，作为染色质修饰因子所显示的发育和组织特异性效应的一个测试案例。此外，我们表明XTH33很可能是一种完整的质膜蛋白。一个推定的跨膜结构域在一些但不是所有的XTH家族成员中是保守的，这表明它们在作为细胞壁修饰因子发挥作用时可能定位不同。
