Jayne Sandrine, Rothgiesser Karin M, Hottiger Michael O
Institute of Veterinary Biochemistry and Molecular Biology, University of Zurich, Zurich, Switzerland.
J Mol Biol. 2009 Dec 4;394(3):485-95. doi: 10.1016/j.jmb.2009.09.032. Epub 2009 Sep 19.
Coactivator-associated arginine methyltransferase 1 (CARM1) belongs to the protein arginine methyltransferase family. It was reported to methylate histone as well as non-histone proteins and thus to be involved in transcriptional activation and mRNA degradation/stability. Here we report the genetic complementation of carm1-/- cells with wild-type CARM1 or an enzymatic inactive mutant of CARM1 to investigate the requirement of CARM1 and its enzymatic activity for nuclear factor kappaB (NF-kappaB)-dependent gene expression. Using custom microarray and quantitative reverse transcription PCR, we could define a subset of NF-kappaB target genes that required CARM1 for their proper expression. Although several tumor necrosis factor-alpha- and phorbol-12-myristate-13-acetate/ionomycin-induced NF-kappaB target genes are CARM1 dependent, CARM1 enzymatic activity was dispensable for gene expression. Interestingly, CARM1 was not required for the stimulus-dependent recruitment of RelA/p65 to chromatin, suggesting that CARM1 is rather contributing in protein complex stabilization. Together, our results confirm the importance of CARM1 as transcriptional cofactor without the involvement of its catalytic activity.
共激活因子相关精氨酸甲基转移酶1（CARM1）属于蛋白质精氨酸甲基转移酶家族。据报道，它可使组蛋白以及非组蛋白甲基化，从而参与转录激活和mRNA降解/稳定性调控。在此，我们报道了用野生型CARM1或CARM1的酶失活突变体对carm1-/-细胞进行基因互补，以研究CARM1及其酶活性对核因子κB（NF-κB）依赖性基因表达的需求。使用定制微阵列和定量逆转录PCR，我们能够确定一组NF-κB靶基因，其正常表达需要CARM1。尽管几种肿瘤坏死因子-α和佛波醇-12-肉豆蔻酸酯-13-乙酸盐/离子霉素诱导的NF-κB靶基因依赖于CARM1，但CARM1的酶活性对于基因表达是可有可无的。有趣的是，刺激依赖性的RelA/p65募集到染色质并不需要CARM1，这表明CARM1在蛋白质复合物稳定化方面发挥了更大作用。总之，我们的结果证实了CARM1作为转录辅因子的重要性，而无需其催化活性的参与。
