Genomes & Developmental Control A concerted action of a paired-type homeobox gene, aristaless, and a homolog of Hox11/tlx homeobox gene, clawless, is essential for the distal tip development of the Drosophila leg

AbstractThe subdivision of the developing field by region-specific expression of genes encoding transcription factors is an essential step duringappendage development in arthropod and vertebrates. In Drosophila leg development, the distal-most region (pretarsus) is specified by theexpression of homeobox genes, aristaless and Lim1, and its immediate neighbor (distal tarsus) is specified by the expression of a pair of Barhomeobox genes. Here, we show that one additional gene, clawless, which is a homolog of vertebrate Hox11/tlx homeobox gene family andformerly known as C15,is specifically expressed in the pretarsus and cooperatively acts with aristaless to repress Bar and possiblyto activateLim1. Similar to aristaless, the maximal expression of clawless requires Lim1 and its co-factor, Chip. Bar attenuates aristaless and clawlessexpression through Lim1 repression. Aristaless and Clawless proteins form a complex capable of binding to specific DNA targets, whichcannot be well recognized solely by Aristaless or Clawless.D 2004 Elsevier Inc. All rights reserved.