Gene Regulation Via Interallelic Interactions in the Drosophila Embryo

Abstract

Non-coding DNA elements regulate transcription during development, but their trans activity is poorly understood. Here, we use RNA live-imaging methods and quantitative analysis to address whether developmental gene expression is affected by interallelic interactions between regulatory sequences in living Drosophila embryos. We show that homologous alleles driven by strongly active developmental enhancers interfere with one another, reducing the transcriptional output of each allele. Conversely, alleles driven by weakly active enhancers do not exhibit interference. We also provide evidence that interference between strong enhancers can be reduced by replacing one of the strong enhancers with a weak enhancer, while interference lacking between weak enhancers cannot be induced by replacing one of the weak enhancers with a strong enhancer. We propose that the level of enhancer activity determines the degree to which alleles engage in interference.