Simpson C G, McQuade C, Lyon J, Brown J W
Cell and Molecular Genetics Department, Scottish Crop Research Institute, Invergowrie, Dundee, UK.
Plant J. 1998 Jul;15(1):125-31. doi: 10.1046/j.1365-313x.1998.00184.x.
The removal of introns from pre-mRNA requires accurate recognition and selection of the intron splice sites. Mutations which alter splice site selection and which lead to skipping of specific exons are indicative of intron/exon recognition mechanisms involving an exon definition process. In this paper, three independent mutants to the COP1 gene in Arabidopsis which show exon skipping were identified and the mutations which alter the normal splicing pattern were characterized. The mutation in cop1-1 was a G-->A change 4 nt upstream from the 3' splice site of intron 5, while the mutation in cop1-2 was a G-->A at the first nucleotide of intron 6, abolishing the conserved G within the 5' splice site consensus. The effect of these mutations was skipping of exon 6. The mutation in cop1-8 was G-->A in the final nucleotide of intron 10 abolishing the conserved G within the 3' splice site consensus and leading to skipping of exon 11. The splicing patterns surrounding exons 6 and 11 of COP1 in these three mutant lines of Arabidopsis provide evidence for exon definition mechanisms operating in plant splicing.
从前体mRNA中去除内含子需要准确识别和选择内含子剪接位点。改变剪接位点选择并导致特定外显子跳跃的突变表明内含子/外显子识别机制涉及外显子定义过程。在本文中，鉴定了拟南芥中三个独立的COP1基因突变体，这些突变体表现出外显子跳跃，并对改变正常剪接模式的突变进行了表征。cop1-1中的突变是内含子5的3'剪接位点上游4个核苷酸处的G→A变化，而cop1-2中的突变是内含子6的第一个核苷酸处的G→A，消除了5'剪接位点共有序列中的保守G。这些突变的影响是外显子6的跳跃。cop1-8中的突变是内含子10的最后一个核苷酸处的G→A，消除了3'剪接位点共有序列中的保守G，并导致外显子11的跳跃。拟南芥这三个突变系中COP1外显子6和11周围的剪接模式为植物剪接中起作用的外显子定义机制提供了证据。
