The transcription factor E2F is required for S phase during Drosophila embryogenesis.
Overexpression of the E2F-1 cDNA in mammalian cells disrupts normal control of the cell cycle and drives cells into S phase. Whereas eliminating E2F activity would test its inferred involvement in the G1-S transition, elimination is complicated by the existence of gene families encoding mammalian E2F. Here we identify mutations in a single essential Drosophila gene, dE2F, that encodes a homolog of the mammalian E2F gene family. Embryos homozygous for null mutations of dE2F complete early cell cycles, presumably using maternal contributions of gene products, but DNA synthesis falls to virtually undetectable levels in cycle 17. Mutant embryos also lack the pulses of coordinate transcription of genes encoding replication functions that usually accompany each transition from quiescence to S phase. We conclude that in most cells dE2F is essential for a G1-S transcriptional program and for G1-S progression.
Duronio
R J
RJ
Department of Biochemistry and Biophysics, University of California, San Francisco 94143, USA.
O'Farrell
P H
PH
Xie
J E
JE
Brook
A
A
Dyson
N
N
D000818:Animals; D030801:Animals, Genetically Modified; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004252:DNA Mutational Analysis; D018076:DNA, Complementary / Q000235:genetics; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000196:embryology* / Q000235:genetics; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; D004625:Embryo, Nonmammalian / Q000378:metabolism; D017344:Genes, Insect; D005816:Genetic Complementation Test; D017403:In Situ Hybridization; D011401:Promoter Regions, Genetic; D056465:Retinoblastoma-Binding Protein 1; D016196:S Phase / Q000502:physiology*; D015534:Trans-Activators; D014157:Transcription Factors / Q000502:physiology*
D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; C088053:Dp transcription factor, Drosophila; D029721:Drosophila Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; D056465:Retinoblastoma-Binding Protein 1; D015534:Trans-Activators; D014157:Transcription Factors