TFII Is Required for Transcription of the Naturally TATA-less but Initiator-containing Vβ Promoter

Abstract

The proximal or core promoter of a typical eukaryotic protein coding gene comprises distinct elements, TATA and/or initiator (Inr). The existence of TATA or Inr at the core promoter suggests that the mechanism of transcription initiation mediated by these two genetic elements may be different. Accordingly, it has been demonstrated that the transcriptional requirements for the TATA-containing, Inr-less ( Transcription initiation of protein coding genes is brought about by RNA polymerase II and a set of general transcription initiation factors (1-3). These factors, in a combinatorial fashion, can direct transcription initiation of a variety of eukaryotic promoters in an in vitro assay (1-3). The core promoter region of a typical eukaryotic gene consists of a TATA box and/or an Inr 1 element (4, 5). The presence of distinct core promoter elements in different genes suggests distinct transcriptional strategies. However, the differences in mechanism of transcriptional initiation mediated by TATA or Inr elements have yet to be elucidated. Biochemical complementation assays employing heat-treated nuclear extracts have demonstrated that the transcription factor requirements for a TATA ϩ InrϪ promoter are different from a TATA Ϫ Inr ϩ promoter (6). The TATA-binding transcription factor complex TFIID is required for both promoters (7), and heat treatment of nuclear extracts (at 49°C for 15 min) renders the TFIID inactive (6, 8). Hence, a heat-treated nuclear extract was incapable of transcribing either a TATAcontaining or a TATA-less promoter unless supplemented with exogenous TFIID (6). Exogenously added TFIID could restore only a TATA ϩ Inr Ϫ promoter activity but not a TATA Ϫ Inr ϩ promoter activity, suggesting that in addition to TFIID, another heat-sensitive component(s) was required for the TATA Ϫ Inr ϩ promoter (6). The mechanism of action of this component is unclear. Because TFIID is required for a TATAless promoter, it is possible that such a factor may serve to anchor TFIID to a TATA (16), and a member of the TBP-associated factors (TAF;6,(17)(18)(19)(20), although other studies have suggested that a TAF may not bind directly to an Inr element (21). However, these observations may not be mutually exclusive. The differences possibly indicate redundancy in Inr element-mediated interactions, which may be condition-and/or promoter context-dependent. In addition, it is possibile that structurally (and perhaps functionally) different classes of Inr elements exist.We wish to elucidate the molecular mechanisms of transcription initiation mediated via an Inr element in TATA Ϫ Inr ϩ promoters. Here, we report that TFII-I (10 -12) is necessary for transcription of a naturally occurring TATA Ϫ Inr ϩ but not for a TATA ϩ Inr Ϫ promoter. For our analyses, we have used the T cell receptor variable region-derived (V␤) promoter (22) Inrϩ V␤ promoter. In each case we have selectively blocked the transcription of the V␤ promoter and subsequently restored its transcriptional activity by exogenous addition of purified TFII-I. We ...

Transcription of the juvenile hormone esterase gene under the control of both an initiator and AT-rich motif

“…see [29]). A number of studies have identified various proteins as binding at or near the initiator motif, such as RNA polymerase II [3], YY1 [30], E2f(HIP1) [5], TAFII150 [1], USF [6], TFIIA [7], TFII-I [8,9] or TFIID itself [10][11][12], but the actual mechanisms of joint interaction of these proteins with the initiator (binding protein) and TFIID are obscure. The role and form of the TATA box are also more complicated than originally conceived.…”

“…TAFII28 and RXR ; [2]). In a number of cases there also appears to be specific binding by factors other than TBP to an ' initiator ' motif downstream from the TBP-binding site [3][4][5][6][7][8][9][10][11][12]. There is increasing evidence that particular DNA sequences in the core promoter, other than the TBP-and initiator-binding motifs, play a pivotal role in controlling whether a particular TBP\TAFII complex [13] or other non-TFIID factor (e.g.…”

Structure-Function Analysis of TFII-I

“…TFII-I is a unique transcription factor, because it can function both as a basal factor and as an activator (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11). Consistent with these functional activities, it has been shown to bind a core promoter element, Inr, and various upstream elements apparently through distinct DNA binding domains (1, 4, 6 -11).…”

Activation of Reg gene, a gene for insulin-producing beta -cell regeneration: Poly(ADP-ribose) polymerase binds Reg promoter and regulates the transcription by autopoly(ADP-ribosyl)ation

“…In the supershift assay, 2 g of antibody for supershift grade (Santa Cruz Biotechnology) were added before the addition of the 32 P-labeled probe. For immunodepletion, nuclear extracts were treated with 2 g of an antibody against PARP (Upstate Biotechnology) or CD38 (24), or of preimmune serum for 10 min at 0°C before the addition of the probe as described (25).…”