title: A gene that regulates the bithorax complex differentially in larval and adult cells of Drosophila.
abstract: Loss-of-function mutations of a new homeotic gene, sxc, in Drosophila cause transformations of body segments, suggesting inappropriate expression of BX-C and ANT-C genes. I present evidence that sxc+ is required during embryogenesis for the selective repression of the BX-C in different larval segments and show that this requirement may be met entirely by maternally derived gene product. sxc+ is also required later in development to ensure the appropriate expression of ANT-C and BX-C genes in adult thoracic and abdominal segments. Absence of sxc+ in the mesothorax apparently results in the ectopic expression of the bx+ (or Ubx+) function in both the anterior and posterior compartments; this suggests that pbx mutations may define a regulatory rather than a structural function.
mesh_terms: D000818:Animals; D002455:Cell Division; D004331:Drosophila melanogaster / Q000033:anatomy & histology / Q000235:genetics* / Q000254:growth & development; D005786:Gene Expression Regulation; D007814:Larva; D009024:Morphogenesis; D010641:Phenotype; D013909:Thorax