NuA4 (nucleosome acetyltransferase of H4) promotes transcriptional initiation of 
TFIID (a complex of TBP and TBP-associated factors [TAFs])-dependent ribosomal 
protein genes involved in ribosome biogenesis. However, it is not clearly 
understood how NuA4 regulates the transcription of ribosomal protein genes. 
Here, we show that NuA4 is recruited to the promoters of ribosomal protein 
genes, such as RPS5, RPL2B, and RPS11B, for TFIID recruitment to initiate 
transcription, and the recruitment of NuA4 to these promoters is impaired in the 
absence of its Eaf1p component. Intriguingly, impaired NuA4 recruitment in a 
Δeaf1 strain depletes recruitment of TFIID (a TAF-dependent form of TBP) but not 
the TAF-independent form of TBP to the promoters of ribosomal protein genes. 
However, in the absence of NuA4, SAGA (Spt-Ada-Gcn5-acetyltransferase) is 
involved in targeting the TAF-independent form of TBP to the promoters of 
ribosomal protein genes for transcriptional initiation. Thus, NuA4 plays an 
important role in targeting TFIID to the promoters of ribosomal protein genes 
for transcriptional initiation in vivo. Such a function is mediated via its 
targeted histone acetyltransferase activity. In the absence of NuA4, ribosomal 
protein genes lose TFIID dependency and become SAGA dependent for 
transcriptional initiation. Collectively, these results provide significant 
insights into the regulation of ribosomal protein gene expression and, hence, 
ribosome biogenesis and functions.