Open AccessPromoter targeting sequence mediates enhancer interference in the Drosophila embryo
Author(s) -
Qing Lin,
Qi Chen,
Lan Lin,
Sheryl T. Smith,
Jumin Zhou
Publication year - 2007
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.0605730104
Subject(s) - enhancer , biology , enhancer trap , enhancer rnas , promoter , transgene , transcription factor , transcription (linguistics) , insulator (electricity) , gene , drosophila melanogaster , genetics , rna interference , microbiology and biotechnology , gene expression , rna , linguistics , philosophy , electrical engineering , engineering
Gene transcription can be regulated by promoter competition when multiple promoters are available for a single enhancer. The converse, however, is largely undescribed. Here we report an occurrence of several enhancers competing for one promoter (enhancer interference) and propose its underlying mechanism. The promoter targeting sequence from theAbdominal-B locus of theDrosophila bithorax complex overcomes the enhancer-blocking activity of insulators in transgenic embryos. It may facilitate the long-range enhancer–promoter communication inAbdominal-B by bypassing insulator elements such asFrontabdominal-7 andFrontabdominal-8 . In transgenic embryos, the anti-insulator activity allowed both an insulator-blocked enhancer and a nonblocked enhancer to contact the same promoter. We found that these two enhancers exhibited mutual inhibition or mutual exclusion in cells where both are transcriptionally active. This enhancer interference occurred at the level of enhancer–promoter communication. It occurred only between enhancers on opposite sides of an insulator and depended on enhancer activity. We hypothesize that enhancer interference limits the interaction of theAbdominal-B promoter to the enhancer(s) from only one regulatory domain in a specific abdominal segment.