Developmental consequences of unrestricted expression of the abd-A gene of Drosophila.
The abdominal-A (abd-A) gene of Drosophila specifies abdominal segments two through eight (A2-A8). We have found that the uniform expression of the abd-A protein under heat shock control transforms embryonic segments anterior to the abd-A domain into an abdominal segment of the A2-A6 type. Posterior abdominal segments and telson undergo little or no transformation, that is, the abd-A product is phenotypically suppressed posterior to its realm of expression. The comparison of wildtype embryos with embryos carrying the heat shock-abd-A construct but no abd-A endogenous product indicate that some elements of the pattern-like shape of denticle belts or ventral pits depend on the amount of abd-A protein. The concurrent expression of abd-A and other homeotic genes suggest competition for common downstream genes. This competition has been studied by looking at the expression on the visceral mesoderm of a gene downstream of abd-A, decapentaplegic, when two homeoproteins with opposing effects on its transcription are simultaneously induced.
Sánchez-Herrero
E
E
Centro de Biología Molecular Severo Ochod, Facultad de Ciencias, Universidad Autónoma de Madrid, Spain.
Guerrero
I
I
Sampedro
J
J
González-Reyes
A
A
D000005:Abdomen / Q000196:embryology / Q000254:growth & development*; D000818:Animals; D004330:Drosophila / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D005801:Genes, Homeobox; D006360:Heat-Shock Proteins / Q000235:genetics; D007814:Larva / Q000254:growth & development / Q000378:metabolism; D010641:Phenotype; D011401:Promoter Regions, Genetic; D013489:Suppression, Genetic; D014170:Transformation, Genetic
D006360:Heat-Shock Proteins