ADA1, a novel component of the ADA/GCN5 complex, has broader effects than GCN5, ADA2, or ADA3 (original) (raw)
Related papers
A novel human Ada2 homologue functions with Gcn5 or Brg1 to coactivate transcription
Molecular and cellular biology, 2003
In yeast, the transcriptional adaptor yeast Ada2 (yAda2) is a part of the multicomponent SAGA complex, which possesses histone acetyltransferase activity through action of the yGcn5 catalytic enzyme. yAda2, among several SAGA proteins, serves to recruit SAGA to genes via interactions with promoter-bound transcription factors. Here we report identification of a new human Ada2 homologue, hAda2beta. Ada2beta differs both biochemically and functionally from the previously characterized hAda2alpha, which is a stable component of the human PCAF (human Gcn5 homologue) acetylase complex. Ada2beta, relative to Ada2alpha, interacted selectively, although not stably, with the Gcn5-containing histone acetylation complex TFTC/STAGA. In addition, Ada2beta interacted with Baf57 (a component of the human Swi/Snf complex) in a yeast two-hybrid screen and associated with human Swi/Snf in vitro. In functional assays, hAda2beta (but not Ada2alpha), working in concert with Gcn5 (but not PCAF) or Brg1 (t...
Regulation of expression of the ada gene controlling the adaptive response
Journal of Molecular Biology, 1989
The Ada protein of Escherichia, coli catalyzes transfer of methyl groups from methylated DNA to its own molecule, and the methylated form of Ada protein promotes transcription of its own gene, ada. Using an in vitro reconstituted system, we found that both the sigma factor and the methylated Ada protein are required for transcription of the ada gene. To elucidate molecular mechanisms involved in the regulation of the ada transcription, we investigated interactions of the non-methylated and methylated forms of Ada protein and the RKA polymerase holo enzyme (the core enzyme and sigma factor) with a DNA fragment, carrying the ada promoter region. Footprinting analyses revealed that t,he methylated Ada protein binds t,o a region from positions-63 to-31, which includes the ada regulatory sequence AAAGCGCA. No firm binding was observed with the nonmethylated Ada protein, although some DNase I-hypersensitive sites were produced in the promo& by both types of Ada protein. RNA polymerase did bind to the promoter once the methylat,ed Ada protein had bound to the upstream sequence. To correlate these phenomena with the process in ,uivo, we used the DKAs derived from promoter-defective mutants. ?l'o binding of Ada protein nor of RNA polymerase occurred with a mutant DNA having a C to G substitution at position-47 within the ada regulatory sequence. In the case of a-35 box mutant with a T to A change at position-34, the methylated Ada protein did bind to the ada regulatory sequence. yet there was no RNA polymerase binding. Thus, the binding of the methylated Ada protein to the upstream region apparently facilitates binding of the RNA polymerase to the proper region of the promot.er. The Ada protein possesses two known methyl acceptor sites, Cys69 and Cys321. The role of methvlation of each cysteinr residue was investigated using mutant forms of the Ada protein."The Ada protein with the cysteine residue at posit*ion 69 replaced by alanine was incapable of binding to the ada promoter even when the cysteine residue at position 321 of the protein was methylated. When the Ada protein wrth alanine at posit,ion 321 was methylated. it acquired the potential to bind to the ada promoter. These results arc compatible with the notion that methylation of the cysteine residue at position 69 causes a conformational change of the Ada protein, thereby faeilit,ating binding of the protein to the upstream regulatory sequence.
Journal of Molecular Biology, 1989
The Ada protein of Escherichia, coli catalyzes transfer of methyl groups from methylated DNA to its own molecule, and the methylated form of Ada protein promotes transcription of its own gene, ada. Using an in vitro reconstituted system, we found that both the sigma factor and the methylated Ada protein are required for transcription of the ada gene. To elucidate molecular mechanisms involved in the regulation of the ada transcription, we investigated interactions of the non-methylated and methylated forms of Ada protein and the RKA polymerase holo enzyme (the core enzyme and sigma factor) with a DNA fragment, carrying the ada promoter region. Footprinting analyses revealed that t,he methylated Ada protein binds t,o a region from positions-63 to-31, which includes the ada regulatory sequence AAAGCGCA. No firm binding was observed with the nonmethylated Ada protein, although some DNase I-hypersensitive sites were produced in the promo& by both types of Ada protein. RNA polymerase did bind to the promoter once the methylat,ed Ada protein had bound to the upstream sequence. To correlate these phenomena with the process in ,uivo, we used the DKAs derived from promoter-defective mutants. ?l'o binding of Ada protein nor of RNA polymerase occurred with a mutant DNA having a C to G substitution at position-47 within the ada regulatory sequence. In the case of a-35 box mutant with a T to A change at position-34, the methylated Ada protein did bind to the ada regulatory sequence. yet there was no RNA polymerase binding. Thus, the binding of the methylated Ada protein to the upstream region apparently facilitates binding of the RNA polymerase to the proper region of the promot.er. The Ada protein possesses two known methyl acceptor sites, Cys69 and Cys321. The role of methvlation of each cysteinr residue was investigated using mutant forms of the Ada protein."The Ada protein with the cysteine residue at posit*ion 69 replaced by alanine was incapable of binding to the ada promoter even when the cysteine residue at position 321 of the protein was methylated. When the Ada protein wrth alanine at posit,ion 321 was methylated. it acquired the potential to bind to the ada promoter. These results arc compatible with the notion that methylation of the cysteine residue at position 69 causes a conformational change of the Ada protein, thereby faeilit,ating binding of the protein to the upstream regulatory sequence.
Molecular and Cellular Biology, 1993
We describe the isolation of a yeast gene, ADA3, mutations in which prevent the toxicity of GAL4-VP16 in vivo. Toxicity was previously proposed to be due to the trapping of general transcription factors required at RNA polymerase II promoters (S. L. Berger, B. Piña, N. Silverman, G. A. Marcus, J. Agapite, J. L. Regier, S. J. Triezenberg, and L. Guarente, Cell 70:251-265, 1992). trans activation by VP16 as well as the acidic activation domain of GCN4 is reduced in the mutant. Other activation domains, such as those of GAL4 and HAP4, are only slightly affected in the mutant. This spectrum is similar to that observed for mutants with lesions in ADA2, a gene proposed to encode a transcriptional adaptor. The ADA3 gene is not absolutely essential for cell growth, but gene disruption mutants grow slowly and are temperature sensitive. Strains doubly disrupted for ada2 and ada3 grow no more slowly than single mutants, providing further evidence that these genes function in the same pathway. ...
Proceedings of the National Academy of Sciences, 1991
The adaptive response of Escherichia coli protects cells against the mutagenic and toxic effects of alkylating agents. This response is controlled by the Ada protein, which not only functions as the transcriptional activator of the ada and alkA genes but also possesses two DNA methyltransferase activities. Ada is converted into an efficient transcriptional activator by transferring a methyl group from a DNA methylphosphotriester to its own Cys-69 residue and then binds to a DNA sequence (the Ada box) present in both the ada and alkA promoters. Although the Ada protein initially appeared to regulate the ada and alk4 genes in a similar fashion, our studies show that the wild-type Ada protein and its truncated derivatives can differentially regulate ada and alk4 transcription. In vivo, lower levels of wild-type methylated Ada are needed to activate ada transcription than alk4 transcription. In cells exposed to alkylating agents, the N-terminal half of Ada, which contains the DNA-binding domain, is sufficient for efficient activation of alk4, but not ada, transcription. Moreover, truncated derivatives containing 80-90% of Ada are extremely strong constitutive activators of ada but are only inducible activators of alk4 transcription. These results suggest that the mechanism by which Ada activates ada transcription differs from that by which it activates alkA transcription.
Role for ADA/GCN5 products in antagonizing chromatin-mediated transcriptional repression
Molecular and cellular biology, 1997
The Saccharomyces cerevisiae SWI/SNF complex is a 2-MDa multimeric assembly that facilitates transcriptional enhancement by antagonizing chromatin-mediated transcriptional repression. We show here that mutations in ADA2, ADA3, and GCN5, which are believed to encode subunits of a nuclear histone acetyltransferase complex, cause phenotypes strikingly similar to that of swi/snf mutants. ADA2, ADA3, and GCN5 are required for full expression of all SWI/SNF-dependent genes tested, including HO, SUC2, INO1, and Ty elements. Furthermore, mutations in the SIN1 gene, which encodes a nonhistone chromatin component, or mutations in histone H3 or H4 partially alleviate the transcriptional defects caused by ada/gcn5 or swi/snf mutations. We also find that ada2 swi1, ada3 swi1, and gcn5 swi1 double mutants are inviable and that mutations in SIN1 allow viability of these double mutants. We have partially purified three chromatographically distinct GCN5-dependent acetyltransferase activities, and we...
Genome Biology, 2012
Adenosine deaminases acting on RNA (ADARs) are enzymes that catalyze the chemical conversion of adenosines to inosines in double-stranded RNA (dsRNA) substrates. Because the properties of inosine mimic those of guanosine (inosine will form two hydrogen bonds with cytosine, for example), inosine is recognized as guanosine by the translational cellular machinery . Adenosine-toinosine (A-to-I) RNA 'editing, ' therefore, eff ectively changes the primary sequence of RNA targets.
Gene, 2003
The ADAR1 gene encodes an RNA-specific adenosine deaminase that alters the functional activity of both viral and cellular RNAs by posttranscriptional adenosine-to-inosine RNA editing. The interferon (IFN) responsive PI promoter of the ADAR1 gene possesses an IFNstimulated response element (ISRE) responsible for IFN-inducibility, as well as an adjacent upstream sequence, designated kinase conserved sequence-like (KCS-') element. The KCS-' element is similar to the 15-bp KCS element so far unique to the human and mouse RNAdependent PKR kinase gene promoters. The KCS element of the PKR kinase (PKR) promoter is essential for both basal and IFN-inducible PKR promoter activity. We have now examined the functional properties of the KCS-' element of the ADAR1 PI promoter. Electrophoretic mobility shift assays (EMSAs) detected constitutively expressed nuclear proteins that bound selectively to the ADAR1 KCS-' element. Competition EMSA and antibody supershift assays indicated that ADAR1 KCS-'-binding proteins shared some properties with PKR KCSbinding proteins. However, transient transfection analyses performed with ADAR1 PI promoter constructs possessing deletion and substitution mutant forms of the KCS-' element revealed that the ADAR1 KCS-' element was not essential for either basal or IFN-inducible promoter activity. Substitution of the ADAR1 KCS-' element with the PKR KCS element increased both basal and inducible ADAR1 PI promoter activity. These results suggest that the KCS-' element of the ADAR1 PI promoter is not functionally equivalent to the KCS element of the PKR promoter. q