Characterization of the transvection mediating region of the abdominal-B locus in Drosophila.
Genetic studies have identified an unusual transvection process in the Abdominal-B (Abd-B) locus of Drosophila. In some cases distal infraabdominal (iab) regulatory domains continue to activate the Abd-B promoter even when translocated onto different chromosomes. Transvection depends on an approx. 10 kb genomic DNA sequence, termed the transvection mediating region (tmr), located immediately downstream of the Abd-B transcription unit. Here we report a detailed analysis of this region. Different DNA fragments from the tmr were inserted into a variety of P-transformation vectors. Analyses of reporter gene expression in transgenic embryos and adults identify at least three cis-regulatory elements, including two enhancers (IAB7 and IAB8) and a new insulator DNA (Frontabdominal-8, Fab-8). Evidence is also presented for a Polycomb Response Element (PRE) linked to the IAB8 enhancer, and an internal promoter in the iab-8 domain, which transcribes the iab-7 and iab-8 cis-regulatory DNA, including the Fab-8 insulator. We discuss the significance of these findings with regard to Abd-B transvection and long-range enhancer-promoter interactions in mammalian globin loci.
Zhou
J
J
Dept Mol. Cell Biol., Division of Genetics, University of California, Berkeley, CA 94720, USA. mlevine@uclink4.berkeley.edu
Ashe
H
H
Burks
C
C
Levine
M
M
D018528:ATP-Binding Cassette Transporters; D000818:Animals; D002875:Chromosomes / Q000235:genetics; D004330:Drosophila / Q000196:embryology / Q000235:genetics*; D029721:Drosophila Proteins; D004625:Embryo, Nonmammalian; D004742:Enhancer Elements, Genetic; D005136:Eye Proteins / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics*; D019476:Insect Proteins / Q000235:genetics; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D020218:Response Elements; D001616:beta-Galactosidase / Q000235:genetics
D018528:ATP-Binding Cassette Transporters; C062393:Abd-B proteins, Drosophila; D029721:Drosophila Proteins; D005136:Eye Proteins; D018398:Homeodomain Proteins; D019476:Insect Proteins; C059254:w protein, Drosophila; C050680:y protein, Drosophila; D001616:beta-Galactosidase