Open AccessAIRE Recruits P-TEFb for Transcriptional Elongation of Target Genes in Medullary Thymic Epithelial Cells
Author(s) -
Irena Oven,
Naděžda Brdičková,
Jiří Kohoutek,
Tomaž Vaupotič,
Mojca Narat,
B. Matija Peterlin
Publication year - 2007
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.01085-07
Subject(s) - biology , rna polymerase ii , p tefb , promoter , transcription (linguistics) , ectopic expression , microbiology and biotechnology , gene , chromatin immunoprecipitation , gene expression , genetics , linguistics , philosophy
AIRE is a transcriptional activator that directs the ectopic expression of many tissue-specific genes in medullary thymic epithelial cells, which plays an important role in the negative selection of autoreactive T cells. However, its mechanism of action remains poorly understood. In this study, we found that AIRE regulates the step of elongation rather than initiation of RNA polymerase II. For these effects, AIRE bound and recruited P-TEFb to target promoters in medullary thymic epithelial cells. In these cells, AIRE activated the ectopic transcription of insulin and salivary protein 1 genes. Indeed, by chromatin immunoprecipitation, we found that RNA polymerase II was already engaged on these promoters but was unable to elongate in the absence of AIRE. Moreover, the genetic inactivation of cyclin T1 from P-TEFb abolished the transcription of AIRE-responsive genes and led to lymphocytic infiltration of lacrimal and salivary glands in the CycT1−/− mouse. Our findings reveal critical steps by which AIRE regulates the transcription of genes that control central tolerance in the thymus.