scholarly journals A Novel TATA-Binding Protein-Binding Protein, ABT1, Activates Basal Transcription and Has a Yeast Homolog That Is Essential for Growth

2000 ◽  
Vol 20 (4) ◽  
pp. 1407-1418 ◽  
Author(s):  
Tsukasa Oda ◽  
Kentaro Kayukawa ◽  
Hiroko Hagiwara ◽  
Henrik T. Yudate ◽  
Yasuhiko Masuho ◽  
...  

ABSTRACT Identification of a novel mouse nuclear protein termed activator of basal transcription 1 (mABT1) that associates with the TATA-binding protein (TBP) and enhances basal transcription activity of class II promoters is described. We also identify mABT1 homologous counterparts in Caenorhabditis elegans and Saccharomyces cerevisiae and show the homologous yeast gene to be essential for growth. The mABT1 associated with TBP in HeLa nuclear extracts and with purified mouse TBP in vitro. In addition, ectopically expressed mABT1 was coimmunoprecipitated with endogenous TBP in transfected cells. More importantly, mABT1 significantly enhanced transcription from an adenovirus major late promoter in a reconstituted cell-free system. We furthermore demonstrate that mABT1 consistently enhanced transcription from a reporter gene with a minimal core promoter as well as from reporter genes with various enhancer elements in a cotransfection assay. Taken together, these results suggest that mABT1 is a novel TBP-binding protein which can function as a basal transcription activator.

1999 ◽  
Vol 19 (4) ◽  
pp. 2835-2845 ◽  
Author(s):  
Tamara A. Muldrow ◽  
Allyson M. Campbell ◽  
P. Anthony Weil ◽  
David T. Auble

ABSTRACT MOT1 is an ATPase which can dissociate TATA binding protein (TBP)-DNA complexes in a reaction requiring ATP hydrolysis. Consistent with this observation, MOT1 can repress basal transcription in vitro. Paradoxically, however, some genes, such as HIS4, appear to require MOT1 as an activator of transcription in vivo. To further investigate the function of MOT1 in basal transcription, we performed in vitro transcription reactions using yeast nuclear extracts depleted of MOT1. Quantitation of MOT1 revealed that it is an abundant protein, with nuclear extracts from wild-type cells containing a molar excess of MOT1 over TBP. Surprisingly, MOT1 can weakly activate basal transcription in vitro. This activation by MOT1 is detectable with amounts of MOT1 that are approximately stoichiometric to TBP. With amounts of MOT1 similar to those present in wild-type nuclear extracts, MOT1 behaves as a weak repressor of basal transcription. These results suggest that MOT1 might activate transcription via an indirect mechanism in which limiting TBP can be liberated from nonpromoter sites for use at promoters. In support of this idea, excess nonpromoter DNA sequesters TBP and represses transcription, but this effect can be reversed by addition of MOT1. These results help to reconcile previous in vitro and in vivo results and expand the repertoire of transcriptional control strategies to include factor-assisted redistribution of TBP between promoter and nonpromoter sites.


1990 ◽  
Vol 10 (2) ◽  
pp. 480-485
Author(s):  
D J Klemm ◽  
W J Roesler ◽  
J S Liu ◽  
E A Park ◽  
R W Hanson

A cell-free system for the study of transcription from the promoter of the phosphoenolpyruvate carboxykinase (GTP) gene by using nuclear extracts from rat tissues was developed. The level of basal transcription from the phosphoenolpyruvate carboxykinase (PEPCK) promoter between -490 and +73 was highest when extracts from liver nuclei, rather than kidney, spleen, and HeLa nuclear extracts, were used. A series of 5' deletions and block mutations were also tested for their effects on basal transcription in vitro. The promoter truncated to -355 had the highest rate of basal transcription, while subsequent deletion to -277 markedly decreased the rate of transcription. Further deletion of the promoter to -134 resulted in a twofold increase in the basal level of transcription compared with that of the promoter deleted to -277. However, subsequent deletion of the NF-1-CCAAT-binding transcription factor binding site or the proximal cyclic AMP (cAMP) regulatory element caused a decrease in basal transcription. Block mutations were inserted into nine specific protein-binding regions of the PEPCK promoter previously shown to be of functional significance or to bind nuclear proteins. Mutation of the TATA box resulted in a 94% decrease in the level of transcription noted with the intact promoter, while sequence substitutions within the proximal cAMP regulatory element decreased the transcription rate to 25%. The addition of the catalytic subunit of cAMP-dependent protein kinase to the in vitro system stimulated transcription from the intact promoter or from a promoter deletion to -109. However, a promoter deletion to -68, which removes the proximal cAMP regulatory element, was unresponsive to added protein kinase catalytic subunit. These findings indicate that the PEPCK promoter between -490 and +73 contains sequences responsive to hormonal and tissue-specific factors in nuclei from rat tissues. The sensitivity of this in vitro transcription system closely mimics the process regulating PEPCK transcription in rat tissues and should make it ideal for testing the function of purified transcription factors.


1999 ◽  
Vol 19 (12) ◽  
pp. 7951-7960 ◽  
Author(s):  
Yasutaka Makino ◽  
Shingo Yogosawa ◽  
Kentaro Kayukawa ◽  
Frederic Coin ◽  
Jean-Marc Egly ◽  
...  

ABSTRACT We previously identified a novel TATA-binding protein (TBP)-interacting protein (TIP120) from the rat liver. Here, in an RNA polymerase II (RNAP II)-reconstituted transcription system, we demonstrate that recombinant TIP120 activates the basal level of transcription from various kinds of promoters regardless of the template DNA topology and the presence of TFIIE/TFIIH and TBP-associated factors. Deletion analysis demonstrated that a 412-residue N-terminal domain, which includes an acidic region and the TBP-binding domain, is required for TIP120 function. Kinetic studies suggest that TIP120 functions during preinitiation complex (PIC) formation at the step of RNAP II/TFIIF recruitment to the promoter but not after the completion of PIC formation. Electrophoretic mobility shift assays showed that TIP120 enhanced PIC formation, and TIP120 also stimulated the nonspecific transcription and DNA-binding activity of RNAP II. These lines of evidence suggest that TIP120 is able to activate basal transcription by overcoming a kinetic impediment to RNAP II/TFIIF integration into the TBP (TFIID)-TFIIB-DNA-complex. Interestingly, TIP120 also stimulates RNAP I- and III-driven transcription and binds to RPB5, one of the common subunits of the eukaryotic RNA polymerases, in vitro. Furthermore, in mouse cells, ectopically expressed TIP120 enhances transcription from all three classes (I, II, and III) of promoters. We propose that TIP120 globally regulates transcription through interaction with basal transcription mechanisms common to all three transcription systems.


2000 ◽  
Vol 20 (14) ◽  
pp. 5269-5275 ◽  
Author(s):  
Pavel Aprikian ◽  
Beth Moorefield ◽  
Ronald H. Reeder

ABSTRACT The TATA binding protein (TBP) interacts with two transcription factor complexes, upstream activating factor (UAF) and core factor (CF), to direct transcription by RNA polymerase I (polI) in the yeastSaccharomyces cerevisiae. Previous work indicates that one function of TBP is to serve as a bridge, ennabling UAF to recruit and stabilize the binding of CF (23, 24). In this work we show that, in addition to aiding recruitment, TBP also directly aids CF function. Overexpression of TBP in strains with UAF components deleted will stimulate CF-directed transcription nearly to wild-type levels in vivo. In vitro, increasing the concentration of TBP stimulates CF-directed transcription in the absence of either UAF or its DNA binding site. This dual function of TBP, serving as a critical member of a core promoter complex as well as a contact point for upstream activators, appears similar to the dual roles that TBP also plays in transcription by RNA polII.


1993 ◽  
Vol 13 (11) ◽  
pp. 6733-6741
Author(s):  
X Xu ◽  
C Prorock ◽  
H Ishikawa ◽  
E Maldonado ◽  
Y Ito ◽  
...  

Rel family proteins regulate the expression of genes linked to kappa B-binding motifs. Little is known, however, of the mechanism by which they enhance transcription. We have investigated the ability of the v-Rel and c-Rel oncoproteins to interact with components of the basal transcription machinery. Here we report that both the acidic transcription activation domain mapping to the unique C terminus of chicken c-Rel and the F9 cell-specific activation region common to both v-Rel and c-Rel interact with the TATA-binding protein (TBP) and transcription factor IIB (TFIIB) in vitro and in vivo. We also demonstrate that TPB interaction with Rel activation regions leads to synergistic activation of transcription of a kappa B-linked reporter gene. Combined with the observation that the mouse c-Rel and human RelA proteins also interact with TBP and TFIIB in vitro, these results suggest that association with basal transcription factors is important for the transcriptional activities of Rel family proteins.


1990 ◽  
Vol 10 (2) ◽  
pp. 480-485 ◽  
Author(s):  
D J Klemm ◽  
W J Roesler ◽  
J S Liu ◽  
E A Park ◽  
R W Hanson

A cell-free system for the study of transcription from the promoter of the phosphoenolpyruvate carboxykinase (GTP) gene by using nuclear extracts from rat tissues was developed. The level of basal transcription from the phosphoenolpyruvate carboxykinase (PEPCK) promoter between -490 and +73 was highest when extracts from liver nuclei, rather than kidney, spleen, and HeLa nuclear extracts, were used. A series of 5' deletions and block mutations were also tested for their effects on basal transcription in vitro. The promoter truncated to -355 had the highest rate of basal transcription, while subsequent deletion to -277 markedly decreased the rate of transcription. Further deletion of the promoter to -134 resulted in a twofold increase in the basal level of transcription compared with that of the promoter deleted to -277. However, subsequent deletion of the NF-1-CCAAT-binding transcription factor binding site or the proximal cyclic AMP (cAMP) regulatory element caused a decrease in basal transcription. Block mutations were inserted into nine specific protein-binding regions of the PEPCK promoter previously shown to be of functional significance or to bind nuclear proteins. Mutation of the TATA box resulted in a 94% decrease in the level of transcription noted with the intact promoter, while sequence substitutions within the proximal cAMP regulatory element decreased the transcription rate to 25%. The addition of the catalytic subunit of cAMP-dependent protein kinase to the in vitro system stimulated transcription from the intact promoter or from a promoter deletion to -109. However, a promoter deletion to -68, which removes the proximal cAMP regulatory element, was unresponsive to added protein kinase catalytic subunit. These findings indicate that the PEPCK promoter between -490 and +73 contains sequences responsive to hormonal and tissue-specific factors in nuclei from rat tissues. The sensitivity of this in vitro transcription system closely mimics the process regulating PEPCK transcription in rat tissues and should make it ideal for testing the function of purified transcription factors.


1993 ◽  
Vol 13 (11) ◽  
pp. 6733-6741 ◽  
Author(s):  
X Xu ◽  
C Prorock ◽  
H Ishikawa ◽  
E Maldonado ◽  
Y Ito ◽  
...  

Rel family proteins regulate the expression of genes linked to kappa B-binding motifs. Little is known, however, of the mechanism by which they enhance transcription. We have investigated the ability of the v-Rel and c-Rel oncoproteins to interact with components of the basal transcription machinery. Here we report that both the acidic transcription activation domain mapping to the unique C terminus of chicken c-Rel and the F9 cell-specific activation region common to both v-Rel and c-Rel interact with the TATA-binding protein (TBP) and transcription factor IIB (TFIIB) in vitro and in vivo. We also demonstrate that TPB interaction with Rel activation regions leads to synergistic activation of transcription of a kappa B-linked reporter gene. Combined with the observation that the mouse c-Rel and human RelA proteins also interact with TBP and TFIIB in vitro, these results suggest that association with basal transcription factors is important for the transcriptional activities of Rel family proteins.


1993 ◽  
Vol 13 (7) ◽  
pp. 3841-3849
Author(s):  
B Zenzie-Gregory ◽  
A Khachi ◽  
I P Garraway ◽  
S T Smale

Promoters containing Sp1 binding sites and an initiator element but lacking a TATA box direct high levels of accurate transcription initiation by using a mechanism that requires the TATA-binding protein (TBP). We have begun to address the role of TBP during transcription from Sp1-initiator promoters by varying the nucleotide sequence between -14 and -33 relative to the start site. With each of several promoters containing different upstream sequences, we detected accurate transcription both in vitro and in vivo, but the promoter strengths varied widely, particularly with the in vitro assay. The variable promoter activities correlated with, but were not proportional to, the abilities of the upstream sequences to function as TATA boxes, as assessed by multiple criteria. These results confirm that accurate transcription can proceed in the presence of an initiator, regardless of the sequence present in the -30 region. However, the results reveal a role for this upstream region, most consistent with a model in which initiator-mediated transcription requires binding of TBP to the upstream DNA in the absence of a specific recognition sequence. Moreover, in vivo it appears that the promoter strength is modulated less severely by altering the -30 sequence, consistent with a previous suggestion that TBP is not rate limiting in vivo for TATA-less promoters. Taken together, these results suggest that variations in the structure of a core promoter might alter the rate-limiting step for transcription initiation and thereby alter the potential modes of transcriptional regulation, without severely changing the pathway used to assemble a functional preinitiation complex.


1999 ◽  
Vol 19 (1) ◽  
pp. 86-98 ◽  
Author(s):  
David E. Sterner ◽  
Patrick A. Grant ◽  
Shannon M. Roberts ◽  
Laura J. Duggan ◽  
Rimma Belotserkovskaya ◽  
...  

ABSTRACT SAGA, a recently described protein complex in Saccharomyces cerevisiae, is important for transcription in vivo and possesses histone acetylation function. Here we report both biochemical and genetic analyses of members of three classes of transcription regulatory factors contained within the SAGA complex. We demonstrate a correlation between the phenotypic severity of SAGA mutants and SAGA structural integrity. Specifically, null mutations in the Gcn5/Ada2/Ada3 or Spt3/Spt8 classes cause moderate phenotypes and subtle structural alterations, while mutations in a third subgroup, Spt7/Spt20, as well as Ada1, disrupt the complex and cause severe phenotypes. Interestingly, double mutants (gcn5Δ spt3Δand gcn5Δ spt8Δ) causing loss of a member of each of the moderate classes have severe phenotypes, similar tospt7Δ, spt20Δ, or ada1Δmutants. In addition, we have investigated biochemical functions suggested by the moderate phenotypic classes and find that first, normal nucleosomal acetylation by SAGA requires a specific domain of Gcn5, termed the bromodomain. Deletion of this domain also causes specific transcriptional defects at the HIS3 promoter in vivo. Second, SAGA interacts with TBP, the TATA-binding protein, and this interaction requires Spt8 in vitro. Overall, our data demonstrate that SAGA harbors multiple, distinct transcription-related functions, including direct TBP interaction and nucleosomal histone acetylation. Loss of either of these causes slight impairment in vivo, but loss of both is highly detrimental to growth and transcription.


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