Mcp and Fab-7: molecular analysis of putative boundaries of cis-regulatory domains in the bithorax complex of Drosophila melanogaster.
A very large cis-regulatory region of approximately 300 kb is responsible for the complex patterns of expression of the three homeotic genes of the bithorax complex Ubx, abd-A and Abd-B. This region can be subdivided in nine parasegment-specific regulatory subunits. Recent genetic and molecular analysis has revealed the existence of two novel cis-regulatory elements Mcp and Fab-7. Mcp is located between iab-4 and iab-5, the parasegment-specific regulatory subunits which direct Abd-B in parasegments 9 and 10. Similarly, Fab-7 is located between iab-6 and iab-7, the parasegment 11 and 12-specific regulatory units. Mcp and Fab-7 appear to function as domain boundaries that separate adjacent cis-regulatory units. We report the analysis of two new Mcp mutant deletions (McpH27 and McpB116) that allow us to localize sequences essential for boundary function to a approximately 0.4 kb DNA segment. These essential sequences closely coincide to a approximately 0.3 kb nuclease hypersensitive region in chromatin. We also show that sequences contributing to the Fab-7 boundary appear to be spread over a larger stretch of DNA, but like Mcp have an unusual chromatin structure.
Karch
F
F
Department of Zoology and Animal Biology, University of Geneva, Switzerland.
Galloni
M
M
Sipos
L
L
Gausz
J
J
Gyurkovics
H
H
Schedl
P
P
D000818:Animals; D001483:Base Sequence; D002843:Chromatin / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000235:genetics*; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics*; D017353:Gene Deletion; D005801:Genes, Homeobox; D018398:Homeodomain Proteins; D007301:Insect Hormones / Q000235:genetics*; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009687:Nuclear Proteins; D011506:Proteins / Q000235:genetics*; D012045:Regulatory Sequences, Nucleic Acid; D017422:Sequence Analysis, DNA; D013909:Thorax; D014157:Transcription Factors
C062393:Abd-B proteins, Drosophila; D002843:Chromatin; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D007301:Insect Hormones; D009687:Nuclear Proteins; D011506:Proteins; D014157:Transcription Factors; C066177:Ubx protein, Drosophila; C066591:abd-A protein, Drosophila