Gao Yangbin, Zhang Yi, Zhang Da, Dai Xinhua, Estelle Mark, Zhao Yunde
Section of Cell and Developmental Biology and.
Section of Cell and Developmental Biology and Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093-0116; and.
Proc Natl Acad Sci U S A. 2015 Feb 17;112(7):2275-80. doi: 10.1073/pnas.1500365112. Epub 2015 Feb 2.
Auxin binding protein 1 (ABP1) has been studied for decades. It has been suggested that ABP1 functions as an auxin receptor and has an essential role in many developmental processes. Here we present our unexpected findings that ABP1 is neither required for auxin signaling nor necessary for plant development under normal growth conditions. We used our ribozyme-based CRISPR technology to generate an Arabidopsis abp1 mutant that contains a 5-bp deletion in the first exon of ABP1, which resulted in a frameshift and introduction of early stop codons. We also identified a T-DNA insertion abp1 allele that harbors a T-DNA insertion located 27 bp downstream of the ATG start codon in the first exon. We show that the two new abp1 mutants are null alleles. Surprisingly, our new abp1 mutant plants do not display any obvious developmental defects. In fact, the mutant plants are indistinguishable from wild-type plants at every developmental stage analyzed. Furthermore, the abp1 plants are not resistant to exogenous auxin. At the molecular level, we find that the induction of known auxin-regulated genes is similar in both wild-type and abp1 plants in response to auxin treatments. We conclude that ABP1 is not a key component in auxin signaling or Arabidopsis development.
生长素结合蛋白1（ABP1）已被研究了数十年。有人提出ABP1作为一种生长素受体，在许多发育过程中发挥着重要作用。在此，我们展示了我们意外的发现：在正常生长条件下，ABP1对于生长素信号传导既非必需，对于植物发育也非必要。我们使用基于核酶的CRISPR技术生成了拟南芥abp1突变体，该突变体在ABP1的第一个外显子中包含一个5个碱基对的缺失，这导致了移码并引入了早期终止密码子。我们还鉴定出一个T-DNA插入型abp1等位基因，其在第一个外显子的ATG起始密码子下游27个碱基对处有一个T-DNA插入。我们表明这两个新的abp1突变体是无效等位基因。令人惊讶的是，我们新的abp1突变体植株没有表现出任何明显的发育缺陷。事实上，在分析的每个发育阶段突变体植株与野生型植株都没有区别。此外，abp1植株对外源生长素不具有抗性。在分子水平上，我们发现已知的生长素调控基因在野生型和abp1植株中对生长素处理的诱导情况相似。我们得出结论，ABP1不是生长素信号传导或拟南芥发育中的关键成分。
