A majority of m6A residues are in the last exons, allowing the potential for 3' UTR regulation.
A majority of m6A residues are in the last exons, allowing the potential for 3' UTR regulation.
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DOI：
10.1101/gad.269415.115
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发表时间：
2015-10-01
影响因子：
10.5
通讯作者：
Darnell RB
中科院分区：
文献类型：
--
作者：
Ke S;Alemu EA;Mertens C;Gantman EC;Fak JJ;Mele A;Haripal B;Zucker-Scharff I;Moore MJ;Park CY;Vågbø CB;Kusśnierczyk A;Klungland A;Darnell JE Jr;Darnell RB
Ke等人发现，>70%的m6 A残基存在于最3′端（最后一个）外显子中，在最后一个外显子开始的150-400个核苷酸内急剧上升。该报告还表明了m6 A修饰在调节近端替代polyA选择中的作用。我们采用UV CLIP（交联免疫沉淀），以单核苷酸分辨率准确定位哺乳动物mRNA中的数万个m6 A残基。超过70%的这些残基存在于最3′端（最后一个）外显子中，在最后一个外显子开始的150-400个核苷酸内急剧增加（6倍）。最后一个外显子m6 A的三分之二和mRNA中所有m6 A的>40%存在于3′非翻译区（UTR）;与早期的建议相反，终止密码子周围的m6 A位点没有偏好。此外，m6 A是显着高于非编码最后一个外显子比在下一个到最后一个外显子窝藏终止密码子。我们发现m6 A密度在3′ UTR的早期达到峰值，并且在大脑和肝脏中具有替代polyA（阿帕）使用的转录物中，大脑转录物优先使用远端polyA位点，如报道的那样，并且在最后一个外显子中也显示出较高的近端m6 A密度。此外，当我们通过敲低甲基化酶复合物的组分来减少m6 A甲基化，然后检查661个在最后外显子中具有近端m6 A峰的转录物时，我们确定了一组111个阿帕使用改变的转录物（近端增加约三分之二）。总之，这些观察结果表明m6 A修饰在调节近端替代polyA选择中的作用。
Ke et al. found that >70% of m6A residues are present in the 3′-most (last) exons, with a sharp rise within 150–400 nucleotides of the start of the last exon. This report also suggests a role of m6A modification in regulating proximal alternative polyA choice. We adapted UV CLIP (cross-linking immunoprecipitation) to accurately locate tens of thousands of m6A residues in mammalian mRNA with single-nucleotide resolution. More than 70% of these residues are present in the 3′-most (last) exons, with a very sharp rise (sixfold) within 150–400 nucleotides of the start of the last exon. Two-thirds of last exon m6A and >40% of all m6A in mRNA are present in 3′ untranslated regions (UTRs); contrary to earlier suggestions, there is no preference for location of m6A sites around stop codons. Moreover, m6A is significantly higher in noncoding last exons than in next-to-last exons harboring stop codons. We found that m6A density peaks early in the 3′ UTR and that, among transcripts with alternative polyA (APA) usage in both the brain and the liver, brain transcripts preferentially use distal polyA sites, as reported, and also show higher proximal m6A density in the last exons. Furthermore, when we reduced m6A methylation by knocking down components of the methylase complex and then examined 661 transcripts with proximal m6A peaks in last exons, we identified a set of 111 transcripts with altered (approximately two-thirds increased proximal) APA use. Taken together, these observations suggest a role of m6A modification in regulating proximal alternative polyA choice.