Replication-coupled chromatin assembly is required for the repression of basal transcription in vivo.
The chromatin assembly process coupled to DNA synthesis in the Xenopus oocyte nucleus is significantly more repressive toward basal transcription than chromatin assembly on duplex DNA. We show that chromatin assembly concurrent with DNA synthesis over the promoter region itself is causal for repression. However, the trans-activator Gal4-VP16 both relieves repression and activates transcription regardless of the chromatin assembly pathway. This activation is independent of whether Gal4-VP16 addition occurs before or after chromatin assembly. We propose that replication-coupled chromatin assembly represents a general mechanism to direct the efficient repression of basal transcription. However transcription induction by a specific activator, Gal4-VP16, occurs independent of this chromatin-mediated repression.
Almouzni
G
G
Laboratory of Molecular Embryology, National Institute of Child Health and Human Development, Bethesda, Maryland 20892.
Wolffe
A P
AP
D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism*; D004261:DNA Replication; D004274:DNA, Recombinant / Q000378:metabolism; D004277:DNA, Single-Stranded; D005656:Fungal Proteins / Q000378:metabolism; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D009865:Oocytes / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D017422:Sequence Analysis, DNA; D015534:Trans-Activators / Q000378:metabolism; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014981:Xenopus
D002843:Chromatin; D004274:DNA, Recombinant; D004277:DNA, Single-Stranded; D005656:Fungal Proteins; C070633:Gal-VP16; D012333:RNA, Messenger; D015534:Trans-Activators