BIG:: a calossin-like protein required for polar auxin transport in Arabidopsis
BIG:: a calossin-like protein required for polar auxin transport in Arabidopsis
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DOI：
10.1101/gad.905201
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发表时间：
2001-08-01
影响因子：
10.5
通讯作者：
Chory, J
中科院分区：
文献类型：
--
作者：
Gil, P;Dewey, E;Chory, J
植物生长素极性运输是植物生长素调控的关键环节，也是植物发育过程中某些光调节反应的必需条件。我们已经发现，两个突变体的拟南芥-doc 1，它显示改变表达的光调节基因，和tir 3，已知其减少生长素转运-有类似的缺陷，并定义突变的一个单一的基因，我们已改名为大。BIG与果蝇基因Calossin/Pushover非常相似，Calossin/Pushover是秀丽隐杆线虫和人类基因组中也存在的基因家族的成员。由BIG编码的蛋白质是非凡的大小，560 kD，并含有几个推定的锌指结构域。表达谱分析实验表明，多个光调节基因的表达改变，可以抑制在DOC 1突变体的生长素生物合成基因的过度表达所引起的生长素水平升高，这表明正常的生长素分布是需要保持低水平的表达，这些基因在黑暗中。tir 3与生长素突变体pin 1、pid和axr 1的双突变体在花序生长素依赖性生长中表现出严重缺陷。生长素转运的化学抑制剂改变了生长素外排载体PIN 1在doc 1/tir 3突变体中的细胞内定位，支持BIG是正常生长素外排所必需的观点。
Polar auxin transport is crucial for the regulation of auxin action and required for some light-regulated responses during plant development. We have found that two mutants of Arabidopsis-doc1, which displays altered expression of light-regulated genes, and tir3, known for its reduced auxin transport-have similar defects and define mutations in a single gene that we have renamed BIG. BIG is very similar to the Drosophila gene Calossin/Pushover, a member of a gene family also present in Caenorhabditis elegans and human genomes. The protein encoded by BIG is extraordinary in size, 560 kD, and contains several putative Zn-finger domains. Expression-profiling experiments indicate that altered expression of multiple light-regulated genes in doc1 mutants can be suppressed by elevated levels of auxin caused by overexpression of an auxin biosynthetic gene, suggesting that normal auxin distribution is required to maintain low-level expression of these genes in the dark. Double mutants of tir3 with the auxin mutants pin1, pid, and axr1 display severe defects in auxin-dependent growth of the inflorescence. Chemical inhibitors of auxin transport chan-e the intracellular localization of the auxin efflux carrier PIN1 in doc1/tir3 mutants, supporting the idea that BIG is required for normal auxin efflux.