The Drosophila Polycomb-group gene Enhancer of zeste contains a region with sequence similarity to trithorax.
As is typical of Polycomb-group loci, the Enhancer of zeste [E(z)] gene negatively regulates the segment identity genes of the Antennapedia (ANT-C) and Bithorax (BX-C) gene complexes. A second class of loci, collectively known as the trithorax group, plays an antagonistic role as positive regulators of the ANT-C and BX-C genes. Molecular analysis of the E(z) gene predicts a 760-amino-acid protein product. A region of 116 amino acids near the E(z) carboxy terminus is 41.2% identical (68.4% similar) with a carboxy-terminal region of the trithorax protein. This portion of the trithorax protein is part of a larger region previously shown to share extensive homology with a human protein (ALL-1/Hrx) that is implicated in acute leukemias. Over this same 116 amino acids, E(z) and ALL-1/Hrx are 43.9% identical (68.4% similar). Otherwise, E(z) is not significantly similar to any previously described proteins. As this region of sequence similarity is shared by two proteins with antagonistic functions, we suggest that it may comprise a domain that interacts with a common target, either nucleic acid or protein. Opposite effects on transcription might then be determined by other portions of the two proteins.
Jones
R S
RS
Department of Cellular and Developmental Biology, Harvard University, Cambridge, Massachusetts 02138-2097.
Gelbart
W M
WM
D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D016386:Chromosome Walking; D003001:Cloning, Molecular; D004247:DNA; D004268:DNA-Binding Proteins / Q000235:genetics*; D004330:Drosophila / Q000235:genetics* / Q000254:growth & development; D029721:Drosophila Proteins; D005786:Gene Expression Regulation; D005809:Genes, Regulator; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins; D010641:Phenotype; D063151:Polycomb Repressive Complex 2; D011506:Proteins / Q000235:genetics*; D012097:Repressor Proteins; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D009687:Nuclear Proteins; D011506:Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C063460:Trl protein, Drosophila; D004247:DNA; C083329:E(z) protein, Drosophila; D063151:Polycomb Repressive Complex 2