Two modes of cis-activation of switch transcription by the IgH superenhancer

摘要: B cell isotype switching plays an important role in modulating adaptive immune responses. It occurs response to specific signals that often induce different (I) promoters driving transcription of switch regions, located upstream the Ig heavy chain (IgH) constant genes. The transcribed regions can recombine, leading a change gene and, consequently, antibody isotype. Switch is controlled by superenhancer 3' regulatory region (3'RR) establishes long-range chromatin cis-interactions with I promoters. Most stimuli more than one promoter, and occur on both chromosomes. Therefore, it presently unknown whether induced compete for 3'RR same chromosome. Here we performed single-chromosome RT-qPCR assays examine monoallelically endogenous context. We show there are two modes 3'RR-mediated activation promoters: coactivation competition. nature inducing signal pivotal determining mode activation. Furthermore, provide evidence that, its setting, has bidirectional activity. propose competition mediated may have evolved cope kinetics primary