n nnnThe Arabidopsis thaliana MADS box transcription factors APETALA3(AP3) and PISTILLATA (PI) heterodimerize and are required tospecify petal identity, yet many details of how this regulatoryprocess is effected are unclear. We have identified three relatedgenes, BHLH136/BANQUO1 (BNQ1), BHLH134/BANQUO2 (BNQ2), and BHLH161/BANQUO3(BNQ3), as being directly and negatively regulated by AP3 andPI in petals. BNQ1, BNQ2, and BNQ3 encode products belongingto a family of atypical non-DNA binding basic helix-loop-helix(bHLH) proteins that heterodimerize with and negatively regulatebHLH transcription factors. We show that bnq3 mutants have pale-greensepals and carpels and decreased chlorophyll levels, suggestingthat BNQ3 has a role in regulating light responses. The ap3bnq3 double mutant displays pale second-whorl organs, supportingthe hypothesis that BNQ3 is downstream of AP3. Consistent witha role in light response, we show that the BNQ gene productsregulate the function of HFR1 (for LONG HYPOCOTYL IN FAR-RED1),which encodes a bHLH protein that regulates photomorphogenesisthrough modulating phytochrome and cryptochrome signaling. TheBNQ genes also are required for appropriate regulation of floweringtime. Our results suggest that petal identity is specified inpart through downregulation of BNQ-dependent photomorphogenicand developmental signaling pathways.展开▼
机译:ABSTRACTn FONT> TH> TR> TABLE> n
n TOP n <字体颜色= 464c53>抽象 FONT> n 介绍 n 结果 n 讨论 n 方法 n 参考文献 n FONT> TH> TR> TABLE> n nnn 拟南芥 I> MADS盒转录因子APETALA3 SUP>(AP3)和PISTILLATA(PI)异源二聚体,并且需要 SUP>指定花瓣的身份,但是尚不清楚如何影响此调控 SUP>过程的许多细节。我们确定了三个相关的 SUP>基因, BHLH136 / BANQUO1 I>( BNQ1 I>), BHLH134 / BANQUO2 I>( BNQ2 I>)和 BHLH161 / BANQUO3 I> SUP>( BNQ3 I>),因为它们直接受AP3和 SUP负向调节> PI在花瓣中。 BNQ1 I>, BNQ2 I>和 BNQ3 I>编码 SUP>属于非典型非DNA结合基本螺旋环家族的产物-helix SUP>(bHLH)蛋白与 SUP> bHLH转录因子异二聚并对其负调节。我们显示 bnq3 I>突变体具有浅绿色的 SUP>萼片和心皮,并且叶绿素水平降低,表明表示 BNQ3 I>具有一个在调节光反应中的作用。 ap3 SUP> bnq3 I>双突变体显示出苍白的第二器官,支持 SUP>假设 BNQ3 I>在 AP3 I>。与 SUP>在光响应中的作用一致,我们表明 BNQ I>基因产物 SUP>调节 HFR1 I>的功能(对于 FAR-RED1中的长质子代 I>), SUP>编码一种bHLH蛋白,该蛋白通过调节植物色素和隐色素信号传导来调节光形态发生 SUP>。 SUP> BNQ I>基因对于开花 SUP>时间的适当调节也是必需的。我们的结果表明, SUP>部分通过 BNQ I>依赖性光形态发生 SUP>的下调和发育信号通路来指定花瓣同一性。 SUP>
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