Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P23193 (transcription elongation factor)
 739 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chimeric proteins joining the histone methyltransferase MLL with various fusion partners trigger distinctive lymphoid and myeloid leukemias. Here, we immunopurified proteins associated with ENL, a protein commonly fused to MLL. Identification of these ENL-associated proteins (EAPs) by mass spectrometry revealed enzymes with a known role in transcriptional elongation (RNA polymerase II C-terminal domain kinase [RNAPolII CTD] positive transcription elongation factor b [pTEFb]), and in chromatin modification (histone-H3 methyltransferase DOT1L) as well as other frequent MLL partners (AF4, AF5q31, and LAF4), and polycomb group members (RING1, CBX8, and BCoR). The composition of EAP was further verified by coimmunoprecipitation, 2-hybrid analysis, pull-down, and colocalization experiments. Purified EAP showed a histone H3 lysine 79-specific methylase activity, displayed a robust RNAPolII CTD kinase function, and counteracted the effect of the pTEFb inhibitor 5,6-dichloro-benzimidazole-riboside. In vivo, an ENL knock-down diminished genome-wide as well as gene-specific H3K79 dimethylation, reduced global run-on elongation, and inhibited transient transcriptional reporter activity. According to structure-function data, DOT1L recruitment was important for transformation by the MLL-ENL fusion derivative. These results suggest a function of ENL in histone modification and transcriptional elongation.
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PMID:A role for the MLL fusion partner ENL in transcriptional elongation and chromatin modification. 1785 33

AF4 and ENL family proteins are frequently fused with MLL, and they comprise a higher order complex (designated AEP) containing the P-TEFb transcription elongation factor. Here, we show that AEP is normally recruited to MLL-target chromatin to facilitate transcription. In contrast, MLL oncoproteins fused with AEP components constitutively form MLL/AEP hybrid complexes to cause sustained target gene expression, which leads to transformation of hematopoietic progenitors. Furthermore, MLL-AF6, an MLL fusion with a cytoplasmic protein, does not form such hybrid complexes, but nevertheless constitutively recruits AEP to target chromatin via unknown alternative mechanisms. Thus, AEP recruitment is an integral part of both physiological and pathological MLL-dependent transcriptional pathways. Bypass of its normal recruitment mechanisms is the strategy most frequently used by MLL oncoproteins.
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PMID:A higher-order complex containing AF4 and ENL family proteins with P-TEFb facilitates oncogenic and physiologic MLL-dependent transcription. 2015 63

The increasing number of chromosomal rearrangements involving the human MLL gene, in combination with differences in clinical behavior and outcome for MLL-rearranged leukemia patients, makes it necessary to reflect on the cancer mechanism and to discuss potential therapeutic strategies. To date, 64 different translocations have been identified at the molecular level. With very few exceptions, most of the identified fusion partner genes encode proteins that display no homologies or functional equivalence. Only the most frequent fusion partners (AF4 family members, AF9, ENL, AF10 and ELL) are involved in the positive transcription elongation factor b-dependent activation cycle of RNA polymerase II. Biological functions remain to be elucidated for the other fusion partners. This minireview tries to sum up some of the available data and mechanisms identified in leukemic stem and leukemic tumor cells and link this information with the known functions of mixed lineage leukemia and certain mixed lineage leukemia fusion partners.
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PMID:Mixed lineage leukemia: roles in human malignancies and potential therapy. 2023 11

Misregulation of transcription elongation is proposed to underlie the pathobiology of MLL leukemia. AF4, AF9, and ENL, common MLL fusion partners, are found in complex with positive transcription elongation factor b (P-TEFb). AF9 and its homolog ENL directly interact with AF4 within these complexes. Previously, we designed a peptide that mimics the AF9 binding domain of AF4 and reported that MLL leukemia cell lines are inhibited by it. Extending these studies, we have modified the peptide design in order to avoid recognition by proteases. The peptide is as effective as its predecessor in vitro and enhances survival in mice bearing MLL leukemia cell lines.
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PMID:An AF9/ENL-targted peptide with therapeutic potential in mixed lineage leukemias. 2550 85

Release of paused RNA polymerase II (Pol II) requires incorporation of the positive transcription elongation factor b (P-TEFb) into the super elongation complex (SEC), thus resulting in rapid yet synchronous transcriptional activation. However, the mechanism underlying dynamic transition of P-TEFb from inactive to active state remains unclear. Here, we found that the SEC components are able to compartmentalize and concentrate P-TEFb via liquid-liquid phase separation from the soluble inactive HEXIM1 containing the P-TEFb complex. Specifically, ENL or its intrinsically disordered region is sufficient to initiate the liquid droplet formation of SEC. AFF4 functions together with ENL in fluidizing SEC droplets. SEC droplets are fast and dynamically formed upon serum exposure and required for rapid transcriptional induction. We also found that the fusion of ENL with MLL can boost SEC phase separation. In summary, our results suggest a critical role of multivalent phase separation of SEC in controlling transcriptional pause release.
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PMID:ENL initiates multivalent phase separation of the super elongation complex (SEC) in controlling rapid transcriptional activation. 3227 36