Summary
We have identified the gene bric a brac and show that it is required for pattern formation along the proximal-distal axis of the leg and antenna of Drosophila. In bric a brac mutant legs, the bristle pattern of the three central tarsal segments is transformed towards the pattern of the most proximal tarsal segment. In addition, bric a brac mutant legs and antennae have segmentation defects. bric a brac encodes a nuclear protein that shares a highly conserved domain with two transcription factors from Drosophila. bric a brac function is dosage dependent and is required in a graded manner for the specification of tarsal segments. The graded requirement for bric a brac correlates with its graded expression pattern, suggesting that the concentration of BRIC A BRAC protein specifies segment identity in the tarsus.