Jang Yun Hee, Park Hyo-Young, Lee Keh Chien, Thu May Phyo, Kim Soon-Kap, Suh Mi Chung, Kang Hunseung, Kim Jeong-Kook
Plant Signaling Network Research Center, School of Life Sciences and Biotechnology, Korea University, Seoul, 136-701, Korea.
Plant J. 2014 May;78(4):591-603. doi: 10.1111/tpj.12491. Epub 2014 Apr 23.
During initial spliceosome assembly, SF1 binds to intron branch points and interacts with U2 snRNP auxiliary factor 65 (U2AF65). Here, we present evidence indicating that AtSF1, the Arabidopsis SF1 homolog, interacts with AtU2AF65a and AtU2AF65b, the Arabidopsis U2AF65 homologs. A mutant allele of AtSF1 (At5g51300) that contains a T-DNA insertion conferred pleiotropic developmental defects, including early flowering and abnormal sensitivity to abscisic acid. An AtSF1 promoter-driven GUS reporter assay showed that AtSF1 promoter activity was temporally and spatially altered, and that full AtSF1 promoter activity required a significant proportion of the coding region. DNA chip analyses showed that only a small proportion of the transcriptome was altered by more than twofold in either direction in the AtSF1 mutant. Expression of the mRNAs of many heat shock proteins was more than fourfold higher in the mutant strain; these mRNAs were among those whose expression was increased most in the mutant strain. An RT-PCR assay revealed an altered alternative splicing pattern for heat shock transcription factor HsfA2 (At2g26150) in the mutant; this altered splicing is probably responsible for the increased expression of the target genes induced by HsfA2. Altered alternative splicing patterns were also detected for the transcripts of other genes in the mutant strain. These results suggest that AtSF1 has functional similarities to its yeast and metazoan counterparts.
在初始剪接体组装过程中，SF1结合内含子分支点并与U2 snRNP辅助因子65（U2AF65）相互作用。在此，我们提供证据表明，拟南芥SF1同源物AtSF1与拟南芥U2AF65同源物AtU2AF65a和AtU2AF65b相互作用。含有T-DNA插入的AtSF1（At5g51300）突变等位基因导致多效性发育缺陷，包括早花和对脱落酸的异常敏感性。AtSF1启动子驱动的GUS报告基因检测表明，AtSF1启动子活性在时间和空间上发生了改变，并且完整的AtSF1启动子活性需要相当比例的编码区。DNA芯片分析表明，在AtSF1突变体中，只有一小部分转录组在两个方向上的变化超过两倍。许多热休克蛋白的mRNA在突变菌株中的表达增加了四倍以上；这些mRNA是突变菌株中表达增加最多的mRNA之一。RT-PCR分析显示，突变体中热休克转录因子HsfA2（At2g26150）的可变剪接模式发生了改变；这种改变的剪接可能是导致HsfA2诱导的靶基因表达增加的原因。在突变菌株中还检测到其他基因转录本的可变剪接模式发生了改变。这些结果表明，AtSF1与其酵母和后生动物对应物具有功能相似性。
