The maize Dwarf3 gene encodes a cytochrome P450-mediated early step in Gibberellin biosynthesis.
The maize Dwarf3 gene encodes a cytochrome P450-mediated early step in Gibberellin biosynthesis.
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DOI：
10.1105/tpc.7.8.1307
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发表时间：
1995-08
期刊：
影响因子：
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通讯作者：
R. Winkler;T. Helentjaris
中科院分区：
文献类型：
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作者：
R. Winkler;T. Helentjaris
赤霉素（GAs）是高等植物正常生长发育所必需的植物激素。玉米的Dwarf3（D3）基因编码GA生物合成途径中的早期步骤。我们使用罗伯逊突变体（Mu）转座子标记D3基因，并显示突变等位基因d3.2：：Mu8与Mu8元件连锁。克隆Mu8元件侧翼的DNA，并通过在通过选择d3和连锁遗传标记之间的重组而开发的高分辨率群体中作图，显示其与d3基因座连锁。为了明确地确定克隆基因与D3的同一性，还克隆了D3的第二个突变等位基因（d3.4），并使用d3.2：：Mu8序列作为探针进行表征。发现d3.4有一个新的插入元件，命名为Sleepy，插入外显子。第三个突变等位基因d3.1具有与d3.4相同大小的3'限制性片段，但不同的5'限制性片段，发现其在与d3.4相同的位置含有Sleepy插入。根据系谱、Sleepy插入和限制性内切酶图谱，d3.1似乎代表d3.4的重组衍生物。D3基因编码预测的蛋白质，其与细胞色素P450酶具有显著的序列相似性。D3 mRNA的分析表明，D3转录表达在根，发育中的叶，营养分生组织，和悬浮培养细胞。我们检测到突变等位基因d3.5中D3 mRNA水平降低。
Gibberellins (GAs) are phytohormones required for normal growth and development in higher plants. The Dwarf3 (D3) gene of maize encodes an early step in the GA biosynthesis pathway. We transposon-tagged the D3 gene using Robertson's Mutator (Mu) and showed that the mutant allele d3.2::Mu8 is linked to a Mu8 element. The DNA flanking the Mu8 element was cloned and shown to be linked to the d3 locus by mapping in a high-resolution population developed by selecting for recombination between d3 and linked genetic markers. To establish unambiguously the identity of the cloned gene as D3, a second mutant allele of D3 (d3.4) was also cloned and characterized using the d3.2::Mu8 sequences as a probe. d3.4 was found to have a novel insertion element, named Sleepy, inserted into an exon. A third mutant allele, d3.1, which has the same size 3' restriction fragments as d3.4 but different 5' restriction fragments, was found to contain a Sleepy insertion at the same position as d3.4. On the basis of the pedigree, Sleepy insertion, and restriction map, d3.1 appears to represent a recombinational derivative of d3.4. The D3 gene encodes a predicted protein with significant sequence similarity to cytochrome P450 enzymes. Analysis of D3 mRNA showed that the D3 transcript is expressed in roots, developing leaves, the vegetative meristem, and suspension culture cells. We detected reduced D3 mRNA levels in the mutant allele d3.5.