Study of the functional interaction between Mcp insulators from the Drosophila bithorax complex: effects of insulator pairing on enhancer-promoter communication.
Boundary elements have been found in the Abd-B 3' cis-regulatory region, which is subdivided into a series of iab domains. Previously, a 340-bp insulator-like element, M(340), was identified in one such 755-bp Mcp fragment linked to the PcG-dependent silencer. In this study, we identified a 210-bp core that was sufficient for pairing of sequence-remote Mcp elements. In two-gene transgenic constructs with two Mcp insulators (or their cores) surrounding yellow, the upstream yeast GAL4 sites were able to activate the distal white only if the insulators were in the opposite orientations (head-to-head or tail-to-tail), which is consistent with the looping/bypass model. The same was true for the efficiency of the cognate eye enhancer, while yellow thus isolated in the loop from its enhancers was blocked more strongly. These results indicate that the relative placement and orientation of insulator-like elements can determine proper enhancer-promoter communication.
Kyrchanova
Olga
O
Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia.
Toshchakov
Stepan
S
Parshikov
Alexander
A
Georgiev
Pavel
P
D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000818:Animals; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins / Q000235:genetics; D004331:Drosophila melanogaster / Q000235:genetics*; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D005123:Eye / Q000166:cytology / Q000378:metabolism; D005136:Eye Proteins / Q000235:genetics; D005786:Gene Expression Regulation / Q000235:genetics*; D005801:Genes, Homeobox / Q000235:genetics*; D038101:Insulator Elements / Q000235:genetics*; D020161:Physical Chromosome Mapping; D011401:Promoter Regions, Genetic / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D019076:Transgenes
D018528:ATP-Binding Cassette Transporters; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D005136:Eye Proteins; C052130:GAL4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C059254:w protein, Drosophila