Nogueira Fabio T S, Madi Shahinez, Chitwood Daniel H, Juarez Michelle T, Timmermans Marja C P
Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA.
Genes Dev. 2007 Apr 1;21(7):750-5. doi: 10.1101/gad.1528607.
Small RNAs are important regulators of gene expression. In maize, adaxial/abaxial (dorsoventral) leaf polarity is established by an abaxial gradient of microRNA166 (miR166), which spatially restricts the expression domain of class III homeodomain leucine zipper (HD-ZIPIII) transcription factors that specify adaxial/upper fate. Here, we show that leafbladeless1 encodes a key component in the trans-acting small interfering RNA (ta-siRNA) biogenesis pathway that acts on the adaxial side of developing leaves and demarcates the domains of hd-zipIII and miR166 accumulation. Our findings indicate that tasiR-ARF, a ta-siRNA, and miR166 establish opposing domains along the adaxial-abaxial axis, thus revealing a novel mechanism of pattern formation.
小RNA是基因表达的重要调节因子。在玉米中,叶片的近轴/远轴(背腹)极性是由微小RNA166(miR166)的远轴梯度建立的,它在空间上限制了决定近轴/上部命运的III类同源异型域亮氨酸拉链(HD-ZIPIII)转录因子的表达域。在这里,我们表明无叶1编码反式作用小干扰RNA(ta-siRNA)生物合成途径中的一个关键组分,该途径作用于发育中叶片的近轴侧,并划定了hd-zipIII和miR166积累的区域。我们的研究结果表明,ta-siRNA——tasiR-ARF和miR166沿着近轴-远轴轴建立了相反的区域,从而揭示了一种新的模式形成机制。