IAA8 expression during vascular cell differentiation
IAA8 expression during vascular cell differentiation
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DOI：
10.1023/a:1022039815537
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发表时间：
2003-02-01
影响因子：
5.1
通讯作者：
Jones, AM
中科院分区：
文献类型：
--
作者：
Groover, AT;Pattishall, A;Jones, AM
我们报告的生长素诱导的IAA基因家族的一员，从百日菊，指定zIAA8，这是由叶肉细胞分化为导管元件在体外表达的表征。zIAA8的转录在诱导培养基中细胞分离后3小时内上调，表明细胞在培养早期感知并响应生长因子刺激。在含有生长素和细胞分裂素或单独的生长素的培养基中，zIAA8的转录物水平在培养72小时内保持高水平，但在仅含有细胞分裂素的培养基或缺乏生长因子的对照培养基中较低，表明生长素特异性诱导并且与缺乏对延长的生长素刺激的脱敏一致。原位定位显示zIAA8定位于百日菊幼苗的初生维管系统、根尖和新生叶片。zIAA8在植物中的血管发育过程中表达的观察结果支持了培养物中早期表达反映了正常血管分化过程中的早期事件的假设。拟南芥IAA8的启动子驱动GUS报告基因在拟南芥中的表达模式类似于zIAA8在百日菊中的表达模式，这表明物种之间的顺式调控元件的保守性，并证实了原位定位的结果。叶片中IAA8启动子的维管表达模式反映了扩展叶片中发育调节的生长素梯度。zIAA8和IAA8的表达模式产生了对体外和植物中血管发育的新见解，并为早期血管分化提供了急需的标志物。
We report the characterization of a member of the auxin-induced IAA gene family from zinnia, designated zIAA8, which is expressed by mesophyll cells differentiating as tracheary elements in vitro. Transcription of zIAA8 is upregulated within 3 h after cell isolation in inductive medium, indicating that cells perceive and respond to growth factor stimulus early in culture. Transcript levels of zIAA8 remain high through 72 h of culture in medium containing auxin and cytokinin or auxin alone, but low in medium containing only cytokinin or control medium lacking growth factors, demonstrating auxin-specific induction and consistent with lack of desensitization to prolonged auxin stimulation. In situ localization shows zIAA8 is localized to primary vasculature, root tips, and nascent leaves in zinnia seedlings. The observation that zIAA8 is expressed during vascular development in planta supports the hypothesis that expression early in culture reflects early events during normal vascular differentiation. The promoter of Arabidopsis IAA8 drives expression of the GUS reporter in a pattern in Arabidopsis similar to that for zIAA8 in zinnia, suggesting conservation of cis regulatory elements between the species and confirming the results from in situ localization. The vascular expression pattern of the IAA8 promoter in leaves mirrors the developmentally regulated auxin gradient in expanding leaf blades. The expression patterns of zIAA8 and IAA8 yield new insight into vascular development in vitro and in planta, and provide much needed markers for early vascular differentiation.