NUBBIN and JAGGED define stamen and carpel shape in Arabidopsis
NUBBIN and JAGGED define stamen and carpel shape in Arabidopsis
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DOI：
10.1242/dev.02335
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发表时间：
2006-05-01
期刊：
影响因子：
4.6
通讯作者：
Yanofsky, MF
中科院分区：
文献类型：
--
作者：
Dinneny, JR;Weigel, D;Yanofsky, MF
在侧器官发育过程中，组织的不同生长对于产生形状和大小的变化是必不可少的。以前的研究已经确定锯齿状(JAG)基因是一个关键的形状调节因子，它编码一个假定的C2H2锌指转录因子，促进侧器官的生长。虽然JAG在所有花器官中都有表达，但功能丧失的JAG等位基因对花瓣和花瓣发育的影响最大，这表明JAG可能与雄蕊和心皮中的其他因子起冗余作用。在这里，我们证明了与JAG密切相关的基因nubbin(Nub)是造成这种冗余的原因。与JAG不同，Nub仅在叶、雄蕊和心皮中表达，在花瓣原基中短暂表达。此外，JAG的表达延伸到侧器官的所有细胞层，而Nub仅限于内侧近轴侧。我们的分析集中在雄蕊和雌蕊的发育上，我们发现块茎与JAG冗余地作用于促进花药中带花粉的小孢子囊和包围胚珠的雌蕊的心皮壁的生长。JAG和NUB还冗余地促进心皮壁中近轴细胞类型的分化，并建立正确的细胞层数。功能获得性实验进一步证明了这两种因子在调节器官生长中的重要作用，表明异位核仁的表达足以驱动组织的增殖和细胞层数的放大。
Differential growth of tissues during lateral organ development is essential for producing variation in shape and size. Previous studies have identified JAGGED (JAG), a gene that encodes a putative C2H2 zinc-finger transcription factor, as a key regulator of shape that promotes growth in lateral organs. Although JAG expression is detected in all floral organs, loss-of-function jag alleles have their strongest effects on sepal and petal development, suggesting that JAG may act redundantly with other factors in stamens and carpels. Here, we show that NUBBIN (NUB), a gene closely related to JAG, is responsible for this redundancy. Unlike JAG, NUB is exclusively expressed in leaves, stamens and carpels, and briefly in petal primordia. Furthermore, whereas JAG expression extends into all cell layers of lateral organs, NUB is restricted to the interior adaxial side. Our analysis focuses on stamen and gynoecium development, where we find that NUB acts redundantly with JAG to promote the growth of the pollen-bearing microsporangia of the anthers and the carpel walls of the gynoecium, which enclose the ovules. JAG and NUB also act redundantly to promote the differentiation of adaxial cell types in the carpel walls, and in the establishment of the correct number of cell layers. The important role these two factors play in regulating organ growth is further demonstrated by gain-of-function experiments showing that ectopic NUB expression is sufficient to drive the proliferation of tissues and the amplification of cell-layer number.