Soderholm Adrian, Vunjak Milica, de Almeida Melanie, Popitsch Niko, Podvalnaya Nadezda, Araguas-Rodriguez Pablo, Scinicariello Sara, Nischwitz Emily, Butter Falk, Ketting René F, Ameres Stefan L, Müller-McNicoll Michaela, Zuber Johannes, Versteeg Gijs A
Max Perutz Labs, Vienna BioCenter Campus (VBC), Dr. -Bohrgasse 9, 1030, Vienna, Austria.
University of Vienna, Max Perutz Labs, Department of Microbiology, Immunobiology and Genetics, Dr. -Bohrgasse 9, 1030, Vienna, Austria.
Nucleic Acids Res. 2025 Jun 20;53(12). doi: 10.1093/nar/gkaf545.
Type II interferon (IFNγ) signaling is essential for innate immunity and critical for effective immunological checkpoint blockade in cancer immunotherapy. Genetic screen identification of post-transcriptional regulators of this pathway has been challenging since such factors are often essential for cell viability. Here, we utilize our inducible CRISPR/Cas9 approach to screen for key post-transcriptional regulators of IFNγ signaling, and in this way, we identify ERH and the ERH-associated splicing and RNA export factors MAGOH, SRSF1, and ALYREF. Loss of these factors impairs post-transcriptional mRNA maturation of JAK2, a crucial kinase for IFNγ signaling, resulting in abrogated JAK2 protein levels and diminished IFNγ signaling. Further analysis highlights a critical role for ERH in preventing intron retention in AU-rich regions in specific transcripts, such as JAK2. This regulation is markedly different from previously described retention of GC-rich introns. Overall, these findings reveal that post-transcriptional JAK2 processing is a critical rate-limiting step for the IFNγ-driven innate immune response.
II型干扰素（IFNγ）信号传导对于先天免疫至关重要，且对癌症免疫治疗中有效的免疫检查点阻断至关重要。由于这些因子通常对细胞活力至关重要，因此对该途径的转录后调节因子进行基因筛选鉴定具有挑战性。在这里，我们利用我们的诱导型CRISPR/Cas9方法来筛选IFNγ信号传导的关键转录后调节因子，通过这种方式，我们鉴定出ERH以及与ERH相关的剪接和RNA输出因子MAGOH、SRSF1和ALYREF。这些因子的缺失会损害JAK2（IFNγ信号传导的关键激酶）的转录后mRNA成熟，导致JAK2蛋白水平缺失和IFNγ信号传导减弱。进一步分析突出了ERH在防止特定转录本（如JAK2）富含AU区域的内含子保留方面的关键作用。这种调节与先前描述的富含GC的内含子保留明显不同。总体而言，这些发现表明，转录后JAK2加工是IFNγ驱动的先天免疫反应的关键限速步骤。
