The ordered assembly of a functional preinitiation complex (PIC), composed of 
general transcription factors (GTFs), is a prerequisite for the transcription of 
protein-coding genes by RNA polymerase II. TFIID, comprised of the TATA binding 
protein (TBP) and 13 TBP-associated factors (TAFs), is the GTF that is thought 
to recognize the promoter sequences allowing site-specific PIC assembly. 
Transcriptional cofactors, such as SAGA, are also necessary for tightly 
regulated transcription initiation. The contribution of the two TAF10-containing 
complexes (TFIID, SAGA) to erythropoiesis remains elusive. By ablating TAF10 
specifically in erythroid cells in vivo, we observed a differentiation block 
accompanied by deregulated GATA1 target genes, including Gata1 itself, 
suggesting functional cross talk between GATA1 and TAF10. Additionally, we 
analyzed by mass spectrometry the composition of TFIID and SAGA complexes in 
mouse and human cells and found that their global integrity is maintained, with 
minor changes, during erythroid cell differentiation and development. In 
agreement with our functional data, we show that TAF10 interacts directly with 
GATA1 and that TAF10 is enriched on the GATA1 locus in human fetal erythroid 
cells. Thus, our findings demonstrate a cross talk between canonical TFIID and 
SAGA complexes and cell-specific transcription activators during development and 
differentiation.