The initiator directs the assembly of a transcription factor IID-dependent transcription complex.

Abstract

Highly purified RNA polymerase H was found to be able to weakly recognize the initiator (Inr) present in the adenovirus IVa2 and major late promoters. The association of RNA polymerase H with the Inr was enhanced by the general transcription factors. The Inr was capable of directing the formation of a DNA-protein complex. Transcription competent complexes on the adenovirus major late and IVa2 promoters appear to be formed by alternative pathways mediated through the Inr and/or "TATA" motif. The presence of both motifs, however, is required for efficient transcription utilizing a discrete start site. Complexes formed at either site required transcription factor TFIID, the TATA binding protein. Consistent with this observation, a TFUD requirement was demonstrated for transcription from a mutant adenovirus major late promoter construct lacking a functional TATA motif.Studies on various class II promoters have indicated that distinct cis-acting DNA elements can affect transcription (1, 2). One of these elements is the "TATA box," which in higher eukaryotes is located -30 nucleotides upstream from the initiation site and is thought to position the start site of transcription (3, 4). The initiator (Inr) constitutes a second such element that appears to be present in most RNA polymerase II transcribed genes and encompasses the transcriptional start site (5).Specific initiation of transcription from class II promoters requires at least six protein transcription factors (TFIIA, -IIB, -IID, -IIE, -IIF, and -IIH) in addition to RNA polymerase II (6, 7). TFIID is the only general transcription factor containing DNA binding activity specific for the TATA motif (8,9). Studies have demonstrated that binding ofTFIID to the TATA motif is the first step in the formation of a transcription-competent complex, providing a target site for association of the other general transcription factors and RNA polymerase II (6,(10)(11)(12)(13)(14).Although it was thought initially that most of the RNA polymerase II-transcribed genes contained a TATA motif, it is now clear that many genes do not (15). We began our studies on TATA-less promoters by analyzing the factors required for transcription of the adenovirus IVa2 promoter (Ad-IVa2). The transcriptional start site of the Ad-IVa2 promoter is located 210 nucleotides upstream of the cap site of the adenovirus major late promoter (Ad-MLP) (15). Transcription from the Ad-IVa2 and ML promoters occurs on different DNA strands (15). Using recombinant yeast TFIID, we demonstrated that transcription of this so called TATAless promoter was dependent on TFIID (16). Upon inspection of IVa2 promoter sequences, a TATA-like sequence (5'-TATAGAAA-3') was discovered -20 nucleotides downstream of the IVa2-transcriptional start site (16). An initiator motif was identified in the Ad-IVa2 promoter; in contrast to the TATA motifs, the initiator motifs in the IVa2 and ML promoters were oriented in opposite directions. Accordingly, a model was presented in which the polar nature of the initiator governed th...

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.…”

Accurate Positioning of RNA Polymerase II on a Natural TATA-Less Promoter Is Independent of TATA-Binding-Protein-Associated Factors and Initiator-Binding Proteins

“…Incubation was carried out at 28°C for 45 min. For primer extension analysis, products of transcription reactions were analyzed by using a primer that hybridized to the chloramphenicol acetyltransferase (CAT) gene (5Ј-CTCCATTTTAGCTTCCTTAG-3Ј) (9). For RNase protection analysis, transcription reactions were stopped by the addition of 2 M ammonium acetate-0.05% sodium dodecyl sulfate-0.05 mM EDTA, extracted with phenol-chloroform, and chloroform and ethanol precipitated.…”

“…Gel mobility shift experiments show that a specific, stable complex containing TBP, TFIIB, TFIIF, and highly purified RNAPII can form on the AdMLP, adenovirus IVa2 (AdIVa2), and TdT Inr elements as well as on the TATA-less dihydrofolate reductase (DHFR) promoter (1,9). Template challenge experiments demonstrate that stable preinitiation complex formation on a wide variety of TATA-containing and TATA-less promoters requires TBP, TFIIB, and RNAPII and that TFIID and TFIIF increase and stabilize complex formation.…”

Binding of YY1 to a Site Overlapping a Weak TATA Box Is Essential for Transcription from the Uteroglobin Promoter in Endometrial Cells

“…Some genes contain another core element, the initiator, either alone or in addition to a TATA box, which is also able to direct accurate transcription initiation by RNA polymerase II. Several proteins and multiprotein complexes have been reported to be involved in initiator function; these include RNA polymerase II itself (9), transcription factors like E2F (33), YY1 (50), and USF (13), the putative initiator factor TFII-I (46), and the general transcription factor TFIID through its TBP-associated factor components (24,61).…”