title: Human Polymerase-Associated Factor complex (PAFc) connects the Super Elongation Complex (SEC) to RNA polymerase II on chromatin.
abstract: The Super Elongation Complex (SEC), containing transcription elongation activators/coactivators P-TEFb, ELL2, AFF4/1, ENL, and AF9, is recruited by HIV-1 Tat and mixed lineage leukemia (MLL) proteins to activate the expression of HIV-1 and MLL-target genes, respectively. In the absence of Tat and MLL, however, it is unclear how SEC is targeted to RNA polymerase (Pol) II to stimulate elongation in general. Furthermore, although ENL and AF9 can bind the H3K79 methyltransferase Dot1L, it is unclear whether these bindings are required for SEC-mediated transcription. Here, we show that the homologous ENL and AF9 exist in separate SECs with similar but nonidentical functions. ENL/AF9 contacts the scaffolding protein AFF4 that uses separate domains to recruit different subunits into SEC. ENL/AF9 also exists outside SEC when bound to Dot1L, which is found to inhibit SEC function. The YEATS domain of ENL/AF9 targets SEC to Pol II on chromatin through contacting the human Polymerase-Associated Factor complex (PAFc) complex. This finding explains the YEATS domain's dispensability for leukemogenesis when ENL/AF9 is translocated to MLL, whose interactions with PAFc and DNA likely substitute for the PAFc/chromatin-targeting function of the YEATS domain.
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
authors.forename: Nanhai
authors.initials: N
authors.lastname: He
authors.forename: Caleb K
authors.initials: CK
authors.lastname: Chan
authors.forename: Bijan
authors.initials: B
authors.lastname: Sobhian
authors.forename: Seemay
authors.initials: S
authors.lastname: Chou
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Xue
authors.forename: Min
authors.initials: M
authors.lastname: Liu
authors.forename: Tom
authors.initials: T
authors.lastname: Alber
authors.forename: Monsef
authors.initials: M
authors.lastname: Benkirane
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhou
mesh_terms: D002843:Chromatin / Q000235:genetics / Q000378:metabolism*; D015967:Gene Expression Regulation, Viral / Q000502:physiology; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D000076983:Histone Methyltransferases; D011495:Histone-Lysine N-Methyltransferase / Q000235:genetics / Q000378:metabolism; D006801:Humans; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D051788:Myeloid-Lymphoid Leukemia Protein / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012319:RNA Polymerase II / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D035602:Transcriptional Elongation Factors / Q000235:genetics / Q000378:metabolism*; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000235:genetics / Q000378:metabolism
chemical_list: C471348:AFF4 protein, human; D002843:Chromatin; C497422:KMT2A protein, human; D046912:Multiprotein Complexes; D012097:Repressor Proteins; D035602:Transcriptional Elongation Factors; D054322:tat Gene Products, Human Immunodeficiency Virus; D051788:Myeloid-Lymphoid Leukemia Protein; D000076983:Histone Methyltransferases; D011495:Histone-Lysine N-Methyltransferase; D012319:RNA Polymerase II