To investigate the importance of core promoter elements for tissue-specific 
transcription of RNA polymerase II genes, we examined testis-specific 
transcription in Drosophila melanogaster. Bioinformatic analyses of core 
promoter sequences from 190 genes that are specifically expressed in testes 
identified a 10 bp A/T-rich motif that is identical to the translational control 
element (TCE). The TCE functions in the 5' untranslated region of Mst(3)CGP 
mRNAs to repress translation, and it also functions in a heterologous gene to 
regulate transcription. We found that among genes with focused initiation 
patterns, the TCE is significantly enriched in core promoters of genes that are 
specifically expressed in testes but not in core promoters of genes that are 
specifically expressed in other tissues. The TCE is variably located in core 
promoters and is conserved in melanogaster subgroup species, but conservation 
dramatically drops in more distant species. In transgenic flies, short (300-400 
bp) genomic regions containing a TCE directed testis-specific transcription of a 
reporter gene. Mutation of the TCE significantly reduced but did not abolish 
reporter gene transcription indicating that the TCE is important but not 
essential for transcription activation. Finally, mutation of testis-specific 
TFIID (tTFIID) subunits significantly reduced the transcription of a subset of 
endogenous TCE-containing but not TCE-lacking genes, suggesting that tTFIID 
activity is limited to TCE-containing genes but that tTFIID is not an obligatory 
regulator of TCE-containing genes. Thus, the TCE is a core promoter element in a 
subset of genes that are specifically expressed in testes. Furthermore, the TCE 
regulates transcription in the context of short genomic regions, from variable 
locations in the core promoter, and both dependently and independently of 
tTFIID. These findings set the stage for determining the mechanism by which the 
TCE regulates testis-specific transcription and understanding the dual role of 
the TCE in translational and transcriptional regulation.