Preferential genome targeting of the CBP co-activator by Rel and Smad proteins in early Drosophila melanogaster embryos.
CBP and the related p300 protein are widely used transcriptional co-activators in metazoans that interact with multiple transcription factors. Whether CBP/p300 occupies the genome equally with all factors or preferentially binds together with some factors is not known. We therefore compared Drosophila melanogaster CBP (nejire) ChIP-seq peaks with regions bound by 40 different transcription factors in early embryos, and we found high co-occupancy with the Rel-family protein Dorsal. Dorsal is required for CBP occupancy in the embryo, but only at regions where few other factors are present. CBP peaks in mutant embryos lacking nuclear Dorsal are best correlated with TGF-ß/Dpp-signaling and Smad-protein binding. Differences in CBP occupancy in mutant embryos reflect gene expression changes genome-wide, but CBP also occupies some non-expressed genes. The presence of CBP at silent genes does not result in histone acetylation. We find that Polycomb-repressed H3K27me3 chromatin does not preclude CBP binding, but restricts histone acetylation at CBP-bound genomic sites. We conclude that CBP occupancy in Drosophila embryos preferentially overlaps factors controlling dorso-ventral patterning and that CBP binds silent genes without causing histone hyperacetylation.
The Wenner-Gren Institute, Developmental Biology, Stockholm University, Stockholm, Sweden.
Per-Henrik
PH
Holmqvist
Ann
A
Boija
Philge
P
Philip
Filip
F
Crona
Per
P
Stenberg
Mattias
M
Mannervik
D000818:Animals; D001665:Binding Sites; D019521:Body Patterning / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics / Q000254:growth & development; D047108:Embryonic Development / Q000235:genetics; D056466:Histone Demethylases / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D015398:Signal Transduction; D051901:Smad4 Protein / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000378:metabolism; D050880:p300-CBP Transcription Factors / Q000235:genetics / Q000378:metabolism
D029721:Drosophila Proteins; C112504:Med protein, Drosophila; D009687:Nuclear Proteins; D010750:Phosphoproteins; D051901:Smad4 Protein; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; C062236:dl protein, Drosophila; C064196:dpp protein, Drosophila; D056466:Histone Demethylases; D050880:p300-CBP Transcription Factors