Genetic analysis of the enhancer of zeste locus and its role in gene regulation in Drosophila melanogaster.
The Enhancer of zeste [E(z)] locus of Drosophila melanogaster is implicated in multiple examples of gene regulation during development. First identified as dominant gain-of-function modifiers of the zeste1-white (z-w) interaction, mutant E(z) alleles also produce homeotic transformations. Reduction of E(z)+ activity leads to both suppression of the z-w interaction and ectopic expression of segment identity genes of the Antennapedia and bithorax gene complexes. This latter effect defines E(z) as a member of the Polycomb-group of genes. Analysis of E(z)S2, a temperature-sensitive E(z) allele, reveals that both maternally and zygotically produced E(z)+ activity is required to correctly regulate the segment identity genes during embryonic and imaginal development. As has been shown for other Polycomb-group genes, E(z)+ is required not to initiate the pattern of these genes, but rather to maintain their repressed state. We propose that the E(z) loss-of-function eye color and homeotic phenotypes may both be due to gene derepression, and that the E(z)+ product may be a general repressing factor required for both examples of negative gene regulation.
Jones
R S
RS
Department of Cellular and Developmental Biology, Harvard University, Cambridge, Massachusetts 02138-2097.
Gelbart
W M
WM
D000483:Alleles; D000818:Animals; D002874:Chromosome Mapping; D003433:Crosses, Genetic; D004331:Drosophila melanogaster / Q000235:genetics* / Q000254:growth & development; D004742:Enhancer Elements, Genetic; D005260:Female; D005786:Gene Expression Regulation; D005801:Genes, Homeobox; D005804:Genes, Lethal; D005808:Genes, Recessive; D008297:Male; D009154:Mutation; D010641:Phenotype; D013489:Suppression, Genetic; D013696:Temperature; D014170:Transformation, Genetic