TATA‐binding protein‐associated factor(s) in TFIID function through the initiator to direct basal transcription from a TATA‐less class II promoter

• Published in: The EMBO journal Vol. 13; no. 13; pp. 3115 - 3126
• Main Authors: Martinez, E., Chiang, C.M., Ge, H., Roeder, R.G.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group 01.07.1994
• Subjects: Base Sequence; Biological and medical sciences; Detergents - pharmacology; DNA - metabolism; DNA Nucleotidylexotransferase - genetics; DNA-Binding Proteins - metabolism; Fundamental and applied biological sciences. Psychology; HeLa Cells; Heparin - pharmacology; Humans; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; Promoter Regions, Genetic - drug effects; Protein Binding; RNA Polymerase II - metabolism; Sarcosine - analogs & derivatives; Sarcosine - pharmacology; TATA Box; TATA Box Binding Protein-Like Proteins; TATA-Box Binding Protein; Transcription Factor TFIID; Transcription Factors - isolation & purification; Transcription Factors - metabolism; Transcription, Genetic; Transcription. Transcription factor. Splicing. Rna processing; Sequence specificity; Transcription; Enzyme; Transcription promoter; Transferases; Rodentia; DNA binding protein; Molecular interaction; In vitro; DNA nucleotidylexotransferase; Nucleotidyltransferases; Vertebrata; Mammalia; Gene; Mouse; TATA box; Mechanism of action; Transcription factor TFIID
• ISSN: 0261-4189; 1460-2075
• DOI: 10.1002/j.1460-2075.1994.tb06610.x

The RNA polymerase II (Pol II) basal transcription factor TFIID is composed of the TATA box‐binding protein (TBP) and several TBP‐associated factors (TAFs). TBP is required for Pol II transcription from TATA‐containing and TATA‐less promoters. TATA‐less promoters of mRNA‐encoding genes often contain an initiator element at the transcription start site that is sufficient to direct accurate Pol II transcription. Here we address the mechanisms of functional TBP recruitment to the TATA‐less initiator‐dependent promoter of the mouse terminal deoxynucleotidyl transferase (TdT) gene. We show that the natural TATA‐less TdT initiator region is sufficient to promote low levels of specific transcription in vitro and to direct the assembly of a stable preinitiation complex. In contrast to what is observed for several other promoters lacking a consensus TATA element, the TATA‐binding activity of TBP is not required for the functional recruitment of TFIID to the natural TATA‐less TdT and beta‐polymerase promoters. Moreover, a comparison of TBP and highly purified epitope‐tagged TFIID reveals that one or several TAFs function independently of distal regulatory elements to mediate initiator‐directed (basal) transcription from the natural TATA‐less TdT core promoter in crude nuclear extracts. Furthermore, by using a transcription system reconstituted with purified components, we present the first evidence for a basal transcription function of TAFs through the TdT initiator element. Altogether, our results suggest an alternative pathway for TFIID recruitment to initiator‐dependent TATA‐less class II promoters in which TAF(s) recruit TBP by interacting either directly or indirectly with the initiator region.