title: Patient mutation in AIRE disrupts P-TEFb binding and target gene transcription.
abstract: Autoimmune regulator (AIRE) is a transcription factor that induces the expression of a large subset of otherwise strictly tissue restricted antigens in medullary thymic epithelial cells, thereby enabling their presentation to developing T cells for negative selection. Mutations in AIRE lead to autoimmune-polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED), a rare monogenetic disease. Although it has been reported that AIRE interacts with proteins involved in nuclear transport, DNA-damage response, chromatin remodeling, transcription and pre-mRNA-splicing, the precise mechanism of AIRE-induced tissue restricted antigen expression has remained elusive. In this study, we investigated an APECED patient mutation that causes the loss of the extreme C-terminus of AIRE and found that this mutant protein is transcriptionaly inactive. When tethered heterologously to DNA, this domain could stimulate transcription and splicing by itself. Moreover, the loss of this C-terminus disrupted interactions with the positive transcription elongation factor b (P-TEFb). Via P-TEFb, AIRE increased levels of RNA polymerase II on and enhanced pre-mRNA splicing of heterologous and endogenous target genes. Indeed, the inhibition of CDK9, the kinase subunit of P-TEFb, inhibited AIRE-induced pre-mRNA splicing of these genes. Thus, AIRE requires P-TEFb to activate transcription elongation and co-transcriptional processing of target genes.
authors: Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia. kristina.zumer@helsinki.fi
authors: Kristina
authors: K
authors: Žumer
authors: Ana
authors: A
authors: Plemenitaš
authors: Kalle
authors: K
authors: Saksela
authors: B Matija
authors: BM
authors: Peterlin
mesh_terms: D000818:Animals; D002460:Cell Line; D042863:Cyclin-Dependent Kinase 9 / Q000037:antagonists & inhibitors / Q000502:physiology; D006801:Humans; D051379:Mice; D009154:Mutation; D010766:Phosphorylation; D016884:Polyendocrinopathies, Autoimmune / Q000235:genetics*; D042925:Positive Transcriptional Elongation Factor B / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D012322:RNA Precursors / Q000378:metabolism; D012326:RNA Splicing; D012333:RNA, Messenger / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015533:Transcriptional Activation; D000096927:AIRE Protein
chemical_list: D042863:Cyclin-Dependent Kinase 9; D042925:Positive Transcriptional Elongation Factor B; D012322:RNA Precursors; D012333:RNA, Messenger; D014157:Transcription Factors; D000096927:AIRE Protein