Position-effect variegation in Drosophila depends on dose of the gene encoding the E2F transcriptional activator and cell cycle regulator.
A dominant mutation due to the insertion of a P-element at 93E on the third chromosome of Drosophila melanogaster enhances position-effect variegation. The corresponding gene was cloned by transposon tagging and the sequence of the transcript revealed that it corresponds to the gene encoding the transcriptional activator and cell cycle regulator dE2F. The transposon-tagged allele is homozygous viable, and the insertion of the transposon in an intron correlates with a strong reduction in the amount of transcript. A homozygous lethal null allele was found to behave as a strong enhancer when heterozygous. Overexpression of the gene in transgenic flies has the opposite effect of suppressing variegation. A link is established here, and discussed, between the dose of a transcriptional activator, which controls the cell cycle, and epigenetic silencing of chromosomal domains in Drosophila.
Seum
C
C
Department of Zoology and Animal Biology, University of Geneva, Switzerland.
Spierer
A
A
Pauli
D
D
Szidonya
J
J
Reuter
G
G
Spierer
P
P
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D004247:DNA; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics*; D050684:E2F Transcription Factors; D004742:Enhancer Elements, Genetic; D005127:Eye Color / Q000235:genetics*; D005260:Female; D018628:Gene Dosage; D005786:Gene Expression Regulation; D007301:Insect Hormones; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D012333:RNA, Messenger / Q000378:metabolism; D056465:Retinoblastoma-Binding Protein 1; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C088053:Dp transcription factor, Drosophila; D029721:Drosophila Proteins; D050684:E2F Transcription Factors; D007301:Insect Hormones; D012333:RNA, Messenger; D056465:Retinoblastoma-Binding Protein 1; D015534:Trans-Activators; D014157:Transcription Factors; C050680:y protein, Drosophila; D004247:DNA