Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA.
Cell Rep. 2019 Jun 25;27(13):3760-3769.e4. doi: 10.1016/j.celrep.2019.05.100.
In the eukaryotic cell, spliceosomes assemble onto pre-mRNA cotranscriptionally. Spliceosome assembly takes place in the context of the chromatin environment, suggesting that the state of the chromatin may affect splicing. The molecular details and mechanisms through which chromatin affects splicing, however, are still unclear. Here, we show a role for the histone methyltransferase Set2 and its histone modification, H3K36 methylation, in pre-mRNA splicing through high-throughput sequencing. Moreover, the effect of H3K36 methylation on pre-mRNA splicing is mediated through the chromodomain protein Eaf3. We find that Eaf3 is recruited to intron-containing genes and that Eaf3 interacts with the splicing factor Prp45. Eaf3 acts with Prp45 and Prp19 after formation of the precatalytic B complex around the time of splicing activation, thus revealing the step in splicing that is regulated by H3K36 methylation. These studies support a model whereby H3K36 facilitates recruitment of an "adapter protein" to support efficient, constitutive splicing.
在真核细胞中，剪接体在 RNA 转录共进行时组装到 pre-mRNA 上。剪接体的组装发生在染色质环境中，这表明染色质的状态可能会影响剪接。然而，染色质影响剪接的分子细节和机制尚不清楚。在这里，我们通过高通量测序显示了组蛋白甲基转移酶 Set2 及其组蛋白修饰 H3K36 甲基化在 pre-mRNA 剪接中的作用。此外，H3K36 甲基化对 pre-mRNA 剪接的影响是通过染色质域蛋白 Eaf3 介导的。我们发现 Eaf3 被募集到含有内含子的基因上，并且 Eaf3 与剪接因子 Prp45 相互作用。Eaf3 在剪接激活时围绕预催化 B 复合物形成后与 Prp45 和 Prp19 一起作用，从而揭示了由 H3K36 甲基化调控的剪接步骤。这些研究支持了这样一种模型，即 H3K36 促进“衔接蛋白”的募集，以支持高效、组成型剪接。
