Polycomb-group proteins are involved in silencing processes caused by a transgenic element from the murine imprinted H19/Igf2 region in Drosophila.
A subset of autosomal genes undergo genomic imprinting which results in expression from only the paternal or maternal chromosome. While this phenomenon is restricted to mammals and angiosperms, the underlying silencing mechanisms appear to be evolutionarily conserved. A biallelically unmethylated DNaseI hypersensitive region (A6-A4) between the imprinted Igf2 and H19 genes is conserved in humans and mice and functions as a tissue-specific maintenance element for the imprinted growth factor IGF2. In order to analyse A6-A4 for potentially conserved transcriptional maintenance properties, we have generated transgenic Drosophila harbouring the element in a reporter construct. These flies depicted silencing of the reporter genes lacZ and mini -white. The silenced state of the mini -white gene showed variegation and sensitivity to temperature changes. In addition, two members of the conserved Polycomb group, Enhancer of zeste and Posterior sex combs, were needed for repression. Polycomb group proteins are essential for gene silencing during development. Our results indicate that Polycomb group proteins may also be involved in the regulation of mammalian imprinted genes.
Erhardt
Sylvia
S
ZMBH, University of Heidelberg, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany.
Lyko
Frank
F
Ainscough
Justin F-X
JF
Surani
M Azim
MA
Paro
Renato
R
D000818:Animals; D030801:Animals, Genetically Modified; D017124:Conserved Sequence; D004268:DNA-Binding Proteins / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics*; D004742:Enhancer Elements, Genetic; D020868:Gene Silencing; D017930:Genes, Reporter; D018392:Genomic Imprinting; D007335:Insulin-Like Growth Factor II / Q000235:genetics*; D051379:Mice; D008817:Mice, Mutant Strains; D009124:Muscle Proteins / Q000235:genetics; D009687:Nuclear Proteins / Q000378:metabolism; D010957:Plasmids; D063150:Polycomb Repressive Complex 1; D063151:Polycomb Repressive Complex 2; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated / Q000235:genetics*; D012097:Repressor Proteins / Q000378:metabolism; D013696:Temperature; D014158:Transcription, Genetic; D019076:Transgenes
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; C094335:H19 long non-coding RNA; D009124:Muscle Proteins; D009687:Nuclear Proteins; C066770:Pc protein, Drosophila; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D012097:Repressor Proteins; C071050:Psc protein, Drosophila; D007335:Insulin-Like Growth Factor II; C083329:E(z) protein, Drosophila; D063151:Polycomb Repressive Complex 2; D063150:Polycomb Repressive Complex 1