Promoter recognition in archaea is mediated by transcription factors: identification of transcription factor aTFB from Methanococcus thermolithotrophicus as archaeal TATA-binding protein.

At least two transcription factors, aTFB and aTFA, are required for accurate and faithful in vitro transcription of homologous templates in cell-free extracts from the methanogenic Archaeon Methanococcus thermolithotrophicus. We have recently shown that the function of aTFB can be replaced by eucaryal TATA-binding proteins. Here we demonstrate using template commitment experiments that promoter recognition in an Archaeon is mediated by transcription factors. The archaeal TATA box was identified as recognition site for binding of aTFB by gel shift analyses. aTFB binds also to the TATA box of adenovirus 2 major late promoter suggesting homology of eucaryal and archaeal TATA boxes. Our analyses provide evidence for a common molecular mechanism of transcription initiation by eucaryal RNA polymerases and archaeal RNA polymerase. They indicate also an evolutionary homology for aTFB and TBP.