RNA editing at a limited number of sites is sufficient to prevent MDA5 activation in the mouse brain.
RNA editing at a limited number of sites is sufficient to prevent MDA5 activation in the mouse brain.
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DOI：
10.1371/journal.pgen.1009516
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发表时间：
2021-05
期刊：
影响因子：
4.5
通讯作者：
Kawahara Y
中科院分区：
文献类型：
--
作者：
Kim JI;Nakahama T;Yamasaki R;Costa Cruz PH;Vongpipatana T;Inoue M;Kanou N;Xing Y;Todo H;Shibuya T;Kato Y;Kawahara Y
作用于RNA 1的腺苷脱氨酶（ADAR1）是一种负责腺苷到肌苷RNA编辑的酶，由两个亚型组成：核p110和细胞质p150。小鼠中Adar1或Adar1 p150基因的缺失会导致胚胎死亡，并伴有干扰素刺激基因（ISGs）的过度表达，这是由黑色素瘤分化相关蛋白5 （MDA5）对未编辑的内源性转录本的异常识别引起的。然而，在众多的RNA编辑位点中，有多少RNA位点需要编辑，特别是通过ADAR1 p150来避免MDA5的激活，以及ADAR1 p110是否参与了这一功能仍然是未知的。特别是，ADAR1 p110在小鼠大脑中丰富，少量ADAR1 p150表达，而ADAR1突变引起aicardi - gouti<e:1>综合征，其中大脑是最受影响的器官之一，伴有isg表达升高。因此，了解RNA编辑介导的大脑中MDA5活化的预防尤为重要。在这里，我们建立了Adar1 p110特异性敲除小鼠，在其中未观察到ISGs的上调表达。这一结果表明，ADAR1 p150介导的RNA编辑足以抑制MDA5的激活。因此，我们进一步构建Adar1 p110/Adar2双敲除小鼠，以鉴定Adar1 p150介导的编辑位点。该分析表明，虽然没有观察到ISGs的表达升高，但在Adar1 p110/Adar2双敲除小鼠的大脑中，只有不到2%的编辑位点被保留。值得注意的是，我们发现一些位点被高度编辑，这与野生型小鼠中发现的位点相当，表明存在ADAR1 p150特异性位点。这些数据表明，由少量ADAR1 p150介导的非常有限的位点上的RNA编辑足以阻止MDA5的激活，至少在小鼠大脑中是这样。RNA受各种转录后修饰的影响，这些修饰增加了信息来调节每个RNA的命运。其中一种修饰是RNA编辑，其中双链RNA中的某些腺苷通过作用于RNA的腺苷脱氨酶（ADARs）催化的脱氨反应转化为肌苷。ADAR1和ADAR2是哺乳动物中的活性编辑酶。此外，ADAR1由核p110和细胞质p150亚型组成。然而，每种ADAR的目标和功能的差异尚不完全清楚。先前的研究表明，先天免疫在Adar1 p150基因敲除小鼠中被激活，而在Adar2基因敲除小鼠中未被观察到。在这里，我们建立了adar1p110敲除小鼠。这些突变小鼠在出生后早期表现出高水平的死亡率，而我们证明这是由ADAR1 p110的RNA编辑独立功能引起的。我们进一步生成了Adar1 p110/Adar2双敲除小鼠，在这些双KO小鼠中，先天免疫没有被激活，尽管在这些双KO小鼠的大脑中缺失了超过98%的编辑位点。总的来说，adar1150介导的RNA编辑在非常有限的位点上足以避免先天免疫的激活，至少在小鼠大脑中是这样。
Adenosine deaminase acting on RNA 1 (ADAR1), an enzyme responsible for adenosine-to-inosine RNA editing, is composed of two isoforms: nuclear p110 and cytoplasmic p150. Deletion of Adar1 or Adar1 p150 genes in mice results in embryonic lethality with overexpression of interferon-stimulating genes (ISGs), caused by the aberrant recognition of unedited endogenous transcripts by melanoma differentiation-associated protein 5 (MDA5). However, among numerous RNA editing sites, how many RNA sites require editing, especially by ADAR1 p150, to avoid MDA5 activation and whether ADAR1 p110 contributes to this function remains elusive. In particular, ADAR1 p110 is abundant in the mouse brain where a subtle amount of ADAR1 p150 is expressed, whereas ADAR1 mutations cause Aicardi–Goutières syndrome, in which the brain is one of the most affected organs accompanied by the elevated expression of ISGs. Therefore, understanding RNA editing–mediated prevention of MDA5 activation in the brain is especially important. Here, we established Adar1 p110–specific knockout mice, in which the upregulated expression of ISGs was not observed. This result suggests that ADAR1 p150–mediated RNA editing is enough to suppress MDA5 activation. Therefore, we further created Adar1 p110/Adar2 double knockout mice to identify ADAR1 p150–mediated editing sites. This analysis demonstrated that although the elevated expression of ISGs was not observed, only less than 2% of editing sites were preserved in the brains of Adar1 p110/Adar2 double knockout mice. Of note, we found that some sites were highly edited, which was comparable to those found in wild-type mice, indicating the presence of ADAR1 p150–specific sites. These data suggest that RNA editing at a very limited sites, which is mediated by a subtle amount of ADAR1 p150, is sufficient to prevents MDA5 activation, at least in the mouse brain. RNA is subject to various post-transcriptional modifications, which add the information to regulate the fate of each RNA. One such modification is RNA editing, in which certain adenosine in double-stranded RNAs is converted to inosine by deamination reaction that is catalyzed by adenosine deaminases acting on RNA (ADARs). ADAR1 and ADAR2 are active editing enzymes in mammals. In addition, ADAR1 is composed of nuclear p110 and cytoplasmic p150 isoforms. However, the difference in the targets and the function of each ADAR is not fully understood. Previous studies demonstrate that innate immunity is activated in Adar1 p150 knockout mice, which is not observed in Adar2 knockout mice. Here, we established Adar1 p110 knockout mice. These mutant mice showed high levels of mortality during the early post-natal stages, whereas we demonstrated that this is caused by RNA editing–independent function of ADAR1 p110. We further generated Adar1 p110/Adar2 double knockout mice, in which innate immunity is not activated, although more than 98% of all the editing sites are absent in the brain of these double KO mice. Collectively, ADAR1 150–mediated RNA editing at a very limited sites is sufficient to avoid activation of innate immunity, at least in the mouse brain.
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影响因子：
7
作者：
Braunschweig U;Barbosa-Morais NL;Pan Q;Nachman EN;Alipanahi B;Gonatopoulos-Pournatzis T;Frey B;Irimia M;Blencowe BJ
通讯作者：
Blencowe BJ
DOI：
10.1073/pnas.240464097
发表时间：
2000-12-05
影响因子：
11.1
作者：
Brown, BA;Lowenhaupt, K;Rich, A
通讯作者：
Rich, A
影响因子：
4.8
作者：
George, CX;Wagner, MV;Samuel, CE
通讯作者：
Samuel, CE
影响因子：
2
作者：
Crow, Yanick J.;Chase, Diana S.;Schmidt, Johanna Lowenstein;Szynkiewicz, Marcin;Forte, Gabriella M. A.;Gornall, Hannah L.;Oojageer, Anthony;Anderson, Beverley;Pizzino, Amy;Helman, Guy;Abdel-Hamid, Mohamed S.;Abdel-Salam, Ghada M.;Ackroyd, Sam;Aeby, Alec;Agosta, Guillermo;Albin, Catherine;Allon-Shalev, Stavit;Arellano, Montse;Ariaudo, Giada;Aswani, Vijay;Babul-Hirji, Riyana;Baildam, Eileen M.;Bahi-Buisson, Nadia;Bailey, Kathryn M.;Barnerias, Christine;Barth, Magalie;Battini, Roberta;Beresford, Michael W.;Bernard, Genevieve;Bianchi, Marika;de Villemeur, Thierry Billette;Blair, Edward M.;Bloom, Miriam;Burlina, Alberto B.;Carpanelli, Maria Luisa;Carvalho, Daniel R.;Castro-Gago, Manuel;Cavallini, Anna;Cereda, Cristina;Chandler, Kate E.;Chitayat, David A.;Collins, Abigail E.;Sierra Corcoles, Concepcion;Cordeiro, Nuno J. V.;Crichiutti, Giovanni;Dabydeen, Lyvia;Dale, Russell C.;D'Arrigo, Stefano;De Goede, Christian G. E. L.;De Laet, Corinne;De Waele, Liesbeth M. H.;Denzler, Ines;Desguerre, Isabelle;Devriendt, Koenraad;Di Rocco, Maja;Fahey, Michael C.;Fazzi, Elisa;Ferrie, Colin D.;Figueiredo, Antonio;Gener, Blanca;Goizet, Cyril;Gowrinathan, Nirmala R.;Gowrishankar, Kalpana;Hanrahan, Donncha;Isidor, Bertrand;Kara, Lent;Khan, Nasaim;King, Mary D.;Kirk, Edwin P.;Kumar, Ram;Lagae, Lieven;Landrieu, Pierre;Lauffer, Heinz;Laugel, Vincent;La Piana, Roberta;Lim, Ming J.;Lin, Jean-Pierre S. -M.;Linnankivi, Tarja;Mackay, Mark T.;Marom, Daphna R.;Lourenco, Charles Marques;McKee, Shane A.;Moroni, Isabella;Morton, Jenny E. V.;Moutard, Marie-Laure;Murray, Kevin;Nabbout, Rima;Nampoothiri, Sheela;Nunez-Enamorado, Noemi;Oades, Patrick J.;Olivieri, Ivana;Ostergaard, John R.;Perez-Duenas, Belen;Prendiville, Julie S.;Ramesh, Venkateswaran;Rasmussen, Magnhild;Regal, Luc;Ricci, Federica;Rio, Marlene;Rodriguez, Diana;Roubertie, Agathe;Salvatici, Elisabetta;Segers, Karin A.;Sinha, Gyanranjan P.;Soler, Doriette;Spiegel, Ronen;Stoedberg, Tommy I.;Straussberg, Rachel;Swoboda, Kathryn J.;Suri, Mohnish;Tacke, Uta;Tan, Tiong Y.;Naude, Johann te Water;Teik, Keng Wee;Thomas, Maya Mary;Till, Marianne;Tonduti, Davide;Valente, Enza Maria;Van Coster, Rudy Noel;van der Knaap, Marjo S.;Vassallo, Grace;Vijzelaar, Raymon;Vogt, Julie;Wallace, Geoffrey B.;Wassmer, Evangeline;Webb, Hannah J.;Whitehouse, William P.;Whitney, Robyn N.;Zaki, Maha S.;Zuberi, Sameer M.;Livingston, John H.;Rozenberg, Flore;Lebon, Pierre;Vanderver, Adeline;Orcesi, Simona;Rice, Gillian I.
通讯作者：
Rice, Gillian I.
影响因子：
3.5
作者：
Kawakubo, K;Samuel, CE
通讯作者：
Samuel, CE