The protein encoded by the Drosophila position-effect variegation suppressor gene Su(var)3-9 combines domains of antagonistic regulators of homeotic gene complexes.
Modifier mutations of position-effect variegation (PEV) represent a useful tool for a genetic and molecular dissection of genes connected with chromatin regulation in Drosophila. The Su(var)3-9 gene belongs to the group of haplo suppressor loci which manifest a triplo enhancer effect. Mutations show a strong suppressor effect even in the presence of PEV enhancer mutations, indicating a central role of this gene in the regulation of PEV. By molecular analysis, Su(var)3-9 could be correlated with a 2.4 kb transcript which encodes a putative protein of 635 amino acids containing a chromo domain and a region of homology to Enhancer of zeste and trithorax, two antagonistic regulators of the Antennapedia and Bithorax gene complexes, as well as to the human protein ALL-1/Hrx which is implicated in acute leukemias. This region of homology is found in all four proteins at the C-terminus. The homology of Su(var)3-9 to both negative (Polycomb and Enhancer of zeste) and positive (trithorax) regulators of the Antennapedia and Bithorax complexes also suggests similarities in the molecular processes connected with stable transmission of a determined state and the clonal propagation of heterochromatinization.
Tschiersch
B
B
Institut für Genetik, Martin-Luther-Universität Halle, Germany.
Hofmann
A
A
Krauss
V
V
Dorn
R
R
Korge
G
G
Reuter
G
G
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins / Q000235:genetics; D004330:Drosophila / Q000235:genetics*; D029721:Drosophila Proteins; D005786:Gene Expression Regulation; D015321:Gene Rearrangement; D005801:Genes, Homeobox / Q000235:genetics; D017344:Genes, Insect / Q000235:genetics*; D005809:Genes, Regulator / Q000235:genetics; D016153:Genes, Suppressor / Q000235:genetics*; D015698:Genomic Library; D008297:Male; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D009799:Ocular Physiological Phenomena; D063151:Polycomb Repressive Complex 2; D011506:Proteins / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors; D014158:Transcription, Genetic; D014170:Transformation, Genetic
D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D009687:Nuclear Proteins; D011506:Proteins; D012097:Repressor Proteins; C089148:Su(var)3-9 protein, Drosophila; D014157:Transcription Factors; C063460:Trl protein, Drosophila; C083329:E(z) protein, Drosophila; D063151:Polycomb Repressive Complex 2