JMJD6 cleaves MePCE to release positive transcription elongation factor b (P-TEFb) in higher eukaryotes

• Published in: eLife Vol. 9
• Main Authors: Lee, Schuyler, Liu, Haolin, Hill, Ryan, Chen, Chunjing, Hong, Xia, Crawford, Fran, Kingsley, Molly, Zhang, Qianqian, Liu, Xinjian, Chen, Zhongzhou, Lengeling, Andreas, Bernt, Kathrin Maria, Marrack, Philippa, Kappler, John, Zhou, Qiang, Li, Chuan-Yuan, Xue, Yuhua, Hansen, Kirk, Zhang, Gongyi
• Format: Journal Article
• Language: English
• Published: England eLife Science Publications, Ltd 12.02.2020; eLife Sciences Publications Ltd; eLife Sciences Publications, Ltd
• Subjects: 7SK snRNP; Analysis; Animal models; Animals; Arginine; Binding Sites; Biochemistry and Chemical Biology; Blotting, Western; CDK9; Crystal structure; Deoxyribonucleic acid; DNA; DNA methylation; DNA-directed RNA polymerase; Enzymes; Gene Knockout Techniques; Genes; House mouse; JMJD6; Mass Spectrometry; MePCE; Messenger RNA; Methyltransferases - metabolism; Mice; Novels; P-TEFb; Phosphorylation; Positive Transcriptional Elongation Factor B - metabolism; Proteases; Protein Structure, Tertiary; Proteins; Proteolysis; Receptors, Cell Surface - chemistry; Receptors, Cell Surface - metabolism; Ribonucleoproteins (small nuclear); RNA; RNA polymerase; RNA polymerase II; RNA Polymerase II - metabolism; Transcription (Genetics); Transcription elongation factor b; CDK9; mouse; 7SK snRNP; chemical biology; MePCE; biochemistry; RNA polymerase II; JMJD6; P-TEFb
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/eLife.53930

More than 30% of genes in higher eukaryotes are regulated by promoter-proximal pausing of RNA polymerase II (Pol II). Phosphorylation of Pol II CTD by positive transcription elongation factor b (P-TEFb) is a necessary precursor event that enables productive transcription elongation. The exact mechanism on how the sequestered P-TEFb is released from the 7SK snRNP complex and recruited to Pol II CTD remains unknown. In this report, we utilize mouse and human models to reveal methylphosphate capping enzyme (MePCE), a core component of the 7SK snRNP complex, as the cognate substrate for Jumonji domain-containing 6 (JMJD6)'s novel proteolytic function. Our evidences consist of a crystal structure of JMJD6 bound to methyl-arginine, enzymatic assays of JMJD6 cleaving MePCE in vivo and in vitro, binding assays, and downstream effects of knockout and overexpression on Pol II CTD phosphorylation. We propose that JMJD6 assists bromodomain containing 4 (BRD4) to recruit P-TEFb to Pol II CTD by disrupting the 7SK snRNP complex.