Gene expression is a complex process requiring many control mechanisms to achieve a desired phenotype. DNA accessibility within chromatin is well established as an important determinant of gene expression. By contrast, while mRNA also associates with a complement of proteins, the exact nature of messenger ribonucleoprotein (mRNP) packaging and its functional relevance is not as clear. Recent reports indicate that exon junction complex (EJC)-mediated mRNP packaging renders exon junction-proximal regions inaccessible for mA methylation, and that EJCs reside within the inaccessible interior of globular transcription and export (TREX) complex-associated nuclear mRNPs. We propose that ‘mRNA accessibility’ within mRNPs is an important determinant of gene expression that may modulate the specificity of a broad array of regulatory processes including but not limited to mA methylation.

中文翻译：

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mRNA 在 mRNA 内的可及性是基因表达的决定因素

基因表达是一个复杂的过程，需要许多控制机制才能实现所需的表型。染色质内 DNA 的可及性已被确定为基因表达的重要决定因素。相比之下，虽然 mRNA 也与蛋白质补体相关，但信使核糖核蛋白 (mRNP) 包装的确切性质及其功能相关性尚不清楚。最近的报告表明，外显子连接复合物（EJC）介导的 mRNP 包装使得外显子连接近端区域无法进行 m6A 甲基化，并且 EJC 位于球状转录和输出（TREX）复合物相关核 mRNP 难以进入的内部。我们认为mRNP内的“mRNA可及性”是基因表达的重要决定因素，可以调节广泛的调控过程的特异性，包括但不限于m6A甲基化。