Xie Q, Frugis G, Colgan D, Chua N H
Laboratory of Plant Cell Biology, Institute of Molecular Agrobiology, National University of Singapore, 117604 Singapore.
Genes Dev. 2000 Dec 1;14(23):3024-36. doi: 10.1101/gad.852200.
Auxin plays a key role in lateral root formation, but the signaling pathway for this process is poorly understood. We show here that NAC1, a new member of the NAC family, is induced by auxin and mediates auxin signaling to promote lateral root development. NAC1 is a transcription activator consisting of an N-terminal conserved NAC-domain that binds to DNA and a C-terminal activation domain. This factor activates the expression of two downstream auxin-responsive genes, DBP and AIR3. Transgenic plants expressing sense or antisense NAC1 cDNA show an increase or reduction of lateral roots, respectively. Finally, TIR1-induced lateral root development is blocked by expression of antisense NAC1 cDNA, and NAC1 overexpression can restore lateral root formation in the auxin-response mutant tir1, indicating that NAC1 acts downstream of TIR1.
生长素在侧根形成过程中起关键作用，但该过程的信号传导途径尚不清楚。我们在此表明，NAC家族的新成员NAC1受生长素诱导，并介导生长素信号传导以促进侧根发育。NAC1是一种转录激活因子，由与DNA结合的N端保守NAC结构域和C端激活结构域组成。该因子激活两个下游生长素响应基因DBP和AIR3的表达。分别表达正义或反义NAC1 cDNA的转基因植物显示侧根数量增加或减少。最后，反义NAC1 cDNA的表达阻断了TIR1诱导的侧根发育，而NAC1的过表达可以恢复生长素响应突变体tir1中的侧根形成，这表明NAC1在TIR1的下游起作用。
