The presence of multiple introns is essential for ERECTA expression in Arabidopsis
The presence of multiple introns is essential for ERECTA expression in Arabidopsis
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DOI：
10.1261/rna.2825811
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发表时间：
2011-10-01
期刊：
影响因子：
4.5
通讯作者：
Shpak, Elena D.
中科院分区：
文献类型：
--
作者：
Karve, Rucha;Liu, Wusheng;Shpak, Elena D.
真核生物中的基因表达常常由于内含子的存在而增强。根据特定的基因，这种增强可以是轻微的或非常大的，并发生在转录和转录后水平。拟南芥ERECTA基因包含27个外显子，编码一种受体样激酶，可促进细胞增殖并抑制植物地上器官中的细胞分化。ERECTA的表达非常强烈地依赖于内含子的存在。无内含子的ERECTA基因不能挽救直立突变体植物的表型，并且与含有内含子的相同构建体相比，产生的蛋白质少约500-900倍。这个结果有些令人惊讶，因为ERECTA编码序列上游的区域有效地促进了外源基因的表达。在这里，我们表明，内含子是必不可少的ERECTA mRNA的积累，并在较小程度上，mRNA的翻译利用。由于无内含子ERECTA产生的mRNA在39端降解，我们推测内含子至少部分地通过增加其稳定性来增加mRNA积累。没有一个内含子是绝对必要的ERECTA表达，而是在特定位置的多个内含子增加ERECTA表达的累加方式。内含子促进ERECTA表达的能力可能与剪接过程有关，而与特定的内含子序列无关。
Gene expression in eukaryotes is often enhanced by the presence of introns. Depending on the specific gene, this enhancement can be minor or very large and occurs at both the transcriptional and post-transcriptional levels. The Arabidopsis ERECTA gene contains 27 exons encoding a receptor-like kinase that promotes cell proliferation and inhibits cell differentiation in above-ground plant organs. The expression of ERECTA very strongly depends on the presence of introns. The intronless ERECTA gene does not rescue the phenotype of erecta mutant plants and produces about 500-900 times less protein compared with the identical construct containing introns. This result is somewhat surprising as the region upstream of the ERECTA coding sequence effectively promotes the expression of extraneous genes. Here, we demonstrate that introns are essential for ERECTA mRNA accumulation and, to a lesser extent, for mRNA utilization in translation. Since mRNA produced by intronless ERECTA is degraded at the 39 end, we speculate that introns increase mRNA accumulation through increasing its stability at least in part. No individual intron is absolutely necessary for ERECTA expression, but rather multiple introns in specific locations increase ERECTA expression in an additive manner. The ability of introns to promote ERECTA expression might be linked to the process of splicing and not to a particular intron sequence.