Isoginkgetin (IGG) is a small molecule inhibitor of pre-mRNA splicing. Failure to accurately remove introns could lead to the production of aberrant mRNAs and proteins. The cellular responses to splicing stress are not well defined. Here, we used oligonucleotide microarrays to assess genome wide changes in gene expression associated with exposure to IGG. Two of the 3 enriched pathways identified using PANTHER analysis of differentially expressed transcripts are linked to the ATF4 transcription factor. We confirmed that ATF4 was selectively translated and upregulated in response IGG despite an almost complete block to total protein synthesis. Importantly, partial disruption of the ATF4 gene using CRISPR-mediated gene editing prevented IGG-induced changes in gene expression. Remarkably, another spliceosome inhibitor, pladienolide B, did not inhibit translation, activate ATF4 or increase ATF4-dependent gene expression. Taken together, IGG activates ATF4 and an ATF4-dependent transcriptional response but these effects are not common to all spliceosome inhibitors.

Isoginkgetin (IGG) 是一种前体 mRNA 剪接的小分子抑制剂。未能准确去除内含子可能会导致产生异常的 mRNA 和蛋白质。细胞对剪接应激的反应尚不明确。在这里，我们使用寡核苷酸微阵列来评估与暴露于 IGG 相关的基因表达的全基因组变化。使用差异表达转录本的 PANTHER 分析鉴定的 3 条富集途径中的两条与 ATF4 转录因子相关。我们证实，尽管几乎完全阻止了总蛋白质合成，但 ATF4 仍被选择性翻译和上调以响应 IGG。重要的是，使用 CRISPR 介导的基因编辑对 ATF4 基因的部分破坏阻止了 IGG 诱导的基因表达变化。值得注意的是，另一种剪接体抑制剂，pladienolide B，不抑制翻译、激活 ATF4 或增加 ATF4 依赖性基因表达。总之，IGG 激活 ATF4 和 ATF4 依赖性转录反应，但这些作用并非所有剪接体抑制剂都具有。