The role of transcriptional activator GATA-1 at human beta-globin HS2.
GATA-1 is an erythroid activator that binds beta-globin gene promoters and DNase I hypersensitive sites (HSs) of the beta-globin locus control region (LCR). We investigated the direct role of GATA-1 interaction at the LCR HS2 enhancer by mutating its binding sites within minichromosomes in erythroid cells. Loss of GATA-1 in HS2 did not compromise interaction of NF-E2, a second activator that binds to HS2, nor was DNase I hypersensitivity at HS2 or the promoter of a linked epsilon-globin gene altered. Reduction of NF-E2 using RNAi confirmed the overall importance of this activator in establishing LCR HSs. However, recruitment of the histone acetyltransferase CBP and RNA pol II to HS2 was diminished by GATA-1 loss. Transcription of epsilon-globin was severely compromised with loss of RNA pol II from the transcription start site and reduction of H3 acetylation and H3K4 di- and tri-methylation in coding sequences. In contrast, widespread detection of H3K4 mono-methylation was unaffected by loss of GATA-1 in HS2. These results support the idea that GATA-1 interaction in HS2 has a prominent and direct role in co-activator and pol II recruitment conferring active histone tail modifications and transcription activation to a target gene but that it does not, by itself, play a major role in establishing DNase I hypersensitivity.
Cho
Youngran
Y
Department of Molecular Biology, College of Natural Sciences, Pusan National University, Pusan 609-735, Korea.
Song
Sang-Hyun
SH
Lee
Jong Joo
JJ
Choi
Narae
N
Kim
Chul Geun
CG
Dean
Ann
A
Kim
AeRi
A
D000107:Acetylation; D001665:Binding Sites; D050882:CREB-Binding Protein / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D050982:GATA1 Transcription Factor / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*; D005914:Globins / Q000235:genetics*; D006657:Histones / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D020014:K562 Cells; D019901:Locus Control Region; D008745:Methylation; D009154:Mutation; D050984:NF-E2 Transcription Factor, p45 Subunit / Q000037:antagonists & inhibitors / Q000502:physiology; D016366:Open Reading Frames; D012319:RNA Polymerase II / Q000378:metabolism; D015534:Trans-Activators / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*; D015533:Transcriptional Activation
D050982:GATA1 Transcription Factor; C494688:GATA1 protein, human; D006657:Histones; D050984:NF-E2 Transcription Factor, p45 Subunit; D015534:Trans-Activators; D005914:Globins; D050882:CREB-Binding Protein; D012319:RNA Polymerase II; D003850:Deoxyribonuclease I