Global regulation of erythroid gene expression by transcription factor GATA-1.
Transcription factor GATA-1 is required for erythropoiesis, yet its full actions are unknown. We performed transcriptome analysis of G1E-ER4 cells, a GATA-1-null erythroblast line that undergoes synchronous erythroid maturation when GATA-1 activity is restored. We interrogated more than 9000 transcripts at 6 time points representing the transition from late burst forming unit-erythroid (BFU-E) to basophilic erythroblast stages. Our findings illuminate several new aspects of GATA-1 function. First, the large number of genes responding quickly to restoration of GATA-1 extends the repertoire of its potential targets. Second, many transcripts were rapidly down-regulated, highlighting the importance of GATA-1 in gene repression. Third, up-regulation of some known GATA-1 targets was delayed, suggesting that auxiliary factors are required. For example, induction of the direct GATA-1 target gene beta major globin was late and, surprisingly, required new protein synthesis. In contrast, the gene encoding Fog1, which cooperates with GATA-1 in beta globin transcription, was rapidly induced independently of protein synthesis. Guided by bioinformatic analysis, we demonstrated that selected regions of the Fog1 gene exhibit enhancer activity and in vivo occupancy by GATA-1. These findings define a regulatory loop for beta globin expression and, more generally, demonstrate how transcriptome analysis can be used to generate testable hypotheses regarding transcriptional networks.
The Children's Hospital of Philadelphia, Division of Hematology, University of Pennsylvania, Philadelphia, PA 19104, USA.
John J
JJ
Welch
Jason A
JA
Watts
Christopher R
CR
Vakoc
Yu
Y
Yao
Hao
H
Wang
Ross C
RC
Hardison
Gerd A
GA
Blobel
Lewis A
LA
Chodosh
Mitchell J
MJ
Weiss
D000818:Animals; D002352:Carrier Proteins / Q000235:genetics; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D004742:Enhancer Elements, Genetic / Q000502:physiology; D004900:Erythroblasts / Q000166:cytology / Q000502:physiology*; D050981:Erythroid-Specific DNA-Binding Factors; D004920:Erythropoiesis / Q000235:genetics*; D050982:GATA1 Transcription Factor; D020869:Gene Expression Profiling; D005816:Genetic Complementation Test; D006801:Humans; D051379:Mice; D009687:Nuclear Proteins / Q000235:genetics; D015203:Reproducibility of Results; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*; D014158:Transcription, Genetic / Q000502:physiology
D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; C494688:GATA1 protein, human; C494689:Gata1 protein, mouse; D009687:Nuclear Proteins; D014157:Transcription Factors; C498432:ZFPM1 protein, human; C107310:Zfpm1 protein, mouse