Characterization of a region of the X chromosome of Drosophila including multi sex combs (mxc), a Polycomb group gene which also functions as a tumour suppressor.
Genetic analysis of the 8D3;8D8-9 segment of the Drosophila melanogaster X chromosome has assigned seven complementation groups to this region, three of which are new. A Polycomb group (Pc-G) gene, multi sex combs (mxc), is characterized and mutant alleles are described. Besides common homeotic transformations characteristic of Pc-G mutants that mimic the ectopic gain of function of BX-C and ANT-C genes, mxc mutants show other phenotypes: they zygotically mimic, in males and females, the characteristic lack of germ line seen in progeny of some maternal effect mutants of the so-called posterior group (the grandchildless phenotype). Loss of normal mxc function can promote uncontrolled malignant growth which indicates a possible relationship between Pc-G genes and tumour suppressor genes. We propose that gain-of-function of genes normally repressed by the wild-type mxc product could, in mxc mutants, give rise to an incoherent signal which would be devoid of meaning in normal development. Such a signal could divert somatic and germ line development pathways, provoke the loss of cell affinities, but allow or promote growth.
Centre de Génétique Moléculaire du C.N.R.S., Gif sur Yvette, France.
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Santamaría
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NB
Randsholt
D000483:Alleles; D000818:Animals; D003433:Crosses, Genetic; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics* / Q000254:growth & development; D005260:Female; D005799:Genes, Dominant; D017344:Genes, Insect / Q000502:physiology*; D005804:Genes, Lethal; D016147:Genes, Tumor Suppressor / Q000502:physiology*; D007247:Infertility, Female / Q000235:genetics; D007248:Infertility, Male / Q000235:genetics; D008297:Male; D016296:Mutagenesis; D010641:Phenotype; D063150:Polycomb Repressive Complex 1; D011506:Proteins / Q000235:genetics*; D014960:X Chromosome
D029721:Drosophila Proteins; C066770:Pc protein, Drosophila; D011506:Proteins; D063150:Polycomb Repressive Complex 1