Cross-competition for TATA-binding protein between TATA boxes of the selenocysteine tRNA[Ser]Sec promoter and RNA polymerase II promoters.

In this study we show that the TATA-binding protein (TBP) interacts with the selenocysteine tRNA[Ser]Sec TATA element in a fashion analogous to the TBP-TATA interaction in RNA polymerase (Pol) II-transcribed genes even though the gene is transcribed by Pol III. Recombinant TBPs expressed in Escherichia coli bound to the tRNA[Ser]Sec TATA element. A factor was detected in Xenopus oocyte extracts which contain TBP and bind to the TATA boxes of the tRNA[Ser]Sec gene and various class II genes. Transcription of the microinjected tRNA[Ser]Sec gene was inhibited in Xenopus oocytes by coinjection with the TATA box of the adenovirus major late promoter (AdMLP). Transcription of a 5S gene was not affected under these conditions. These results suggest that the tRNA[Ser]Sec gene recruits TBP in a manner similar to that of TATA-dependent Pol II-transcribed genes and differently from that of Pol III-transcribed genes lacking a TATA box.