College of Agricultural and Life Sciences, Chongqing University, Chongqing 400030, China.
J Genet Genomics. 2010 Jan;37(1):85-99. doi: 10.1016/S1673-8527(09)60028-X.
In several stress responsive gene loci of monocot cereal crops, we have previously identified an unusual posttranscriptional processing mediated by paired presence of short direct repeated (SDR) sequences at 5' and 3' splicing junctions that are distinct from conventional (U2/U12-type) splicing boundaries. By using the known SDR-containing sequences as probes, 24 plant candidate genes involved in diverse functional pathways from both monocots and dicots that potentially possess SDR-mediated posttranscriptional processing were predicted in the GenBank database. The SDRs-mediated posttranscriptional processing events including cis- and trans-actions were experimentally detected in majority of the predicted candidates. Extensive sequence analysis demonstrates several types of SDR-associated splicing peculiarities including partial exon deletion, exon fragment repetition, exon fragment scrambling and trans-splicing that result in either loss of partial exon or unusual exonic sequence rearrangements within or between RNA molecules. In addition, we show that the paired presence of SDR is necessary but not sufficient in SDR-mediated splicing in transient expression and stable transformation systems. We also show prokaryote is incapable of SDR-mediated premRNA splicing.
在单子叶谷类作物的几个应激响应基因座中，我们之前已经鉴定出一种不寻常的转录后处理，这种处理是由 5' 和 3' 剪接连接处短的直接重复 (SDR) 序列的配对存在介导的，与常规 (U2/U12 型) 剪接边界不同。通过使用已知的含有 SDR 的序列作为探针，在 GenBank 数据库中预测了来自单子叶植物和双子叶植物的参与不同功能途径的 24 个植物候选基因，这些基因可能具有 SDR 介导的转录后处理。在大多数预测的候选物中，实验检测到了 SDR 介导的转录后处理事件，包括顺式和反式作用。广泛的序列分析表明，SDR 相关剪接具有几种类型的特殊性，包括部分外显子缺失、外显子片段重复、外显子片段混乱和反式剪接，导致 RNA 分子内或分子间部分外显子缺失或异常外显子序列重排。此外，我们表明，在瞬时表达和稳定转化系统中，SDR 配对存在是 SDR 介导的剪接所必需的，但不是充分的。我们还表明，原核生物不能进行 SDR 介导的前体 RNA 剪接。
