Molecular and Cellular Biology, University of California Davis, CA, USA.
Front Plant Sci. 2011 Dec 13;2:98. doi: 10.3389/fpls.2011.00098. eCollection 2011.
Many introns significantly increase gene expression through a process termed intron-mediated enhancement (IME). Introns exist in the transcribed DNA and the nascent RNA, and could affect expression from either location. To determine which is more relevant to IME, hybrid introns were constructed that contain sequences from stimulating Arabidopsis thaliana introns either in their normal orientation or as the reverse complement. Both ends of each intron are from the non-stimulatory COR15a intron in their normal orientation to allow splicing. The inversions create major alterations to the sequence of the transcribed RNA with relatively minor changes to the DNA structure. Introns containing portions of either the UBQ10 or ATPK1 intron increased expression to a similar degree regardless of orientation. Also, computational predictions of IME improve when both intron strands are considered. These findings are more consistent with models of IME that act at the level of DNA rather than RNA.
许多内含子通过一种称为内含子介导增强（IME）的过程显著增加基因表达。内含子存在于转录的 DNA 和新生 RNA 中，并且可以从任一位点影响表达。为了确定哪个与 IME 更相关，构建了杂种内含子，它们在正常取向或反向互补中包含来自刺激拟南芥内含子的序列。每个内含子的两端都来自正常取向的非刺激 COR15a 内含子，以允许剪接。这些倒位对内转录 RNA 的序列产生了重大改变，而对 DNA 结构的改变相对较小。无论取向如何，包含 UBQ10 或 ATPK1 内含子部分的内含子都将表达增加到相似程度。此外，当同时考虑两条内含子链时，IME 的计算预测会得到改善。这些发现与在 DNA 而非 RNA 水平起作用的 IME 模型更为一致。
