scholarly journals Role of SAGA complex subunits in gene regulation of Candida albicans

2021 ◽  
Vol 3 (12) ◽  
Author(s):  
Saima Rashid ◽  
Tuana Oliveira Correia Mesquita ◽  
Malcolm Whiteway
Keyword(s):  
Gene Regulation ◽  
Candida Albicans ◽  
Transcription Initiation ◽  
Telomere Maintenance ◽  
Initiation Factor ◽  
Saga Complex ◽  
Transcription Initiation Factor ◽  
Depth Study ◽  
Homozygous Deletions

The SAGA (Spt-Ada-Gcn5-acetyltransferase) is an evolutionary conserved multidomain co-activator complex involved in gene regulation through its histone acetyltransferase (HAT) and deubiquitinase (DUB) functions. It is well studied in Saccharomyces cerevisiae, and recent reports from humans and Drosophila expand its importance from gene transcription regulation to transcription elongation, protein stability and telomere maintenance. In Candida albicans, little is known about the components of the SAGA complex and their influence in morphogenesis and stress response. In this work, we analysed individual components of the SAGA complex, their role in morphogenesis and responses to different signalling cues. We initially analysed conditionally repressed strains of SAGA complex subunits involved in the HAT function of the complex: Tra1, Ngg1, Spt7, Spt8, Taf5, Taf6, Taf9, and Taf10. It appears that the Tra1 might be essential for the viability of C. albicans, as we failed to obtain homozygous deletions although it showed detectible growth in the conditionally repressed strain. Also, we observed that TBP- associated factors are essential in C. albicans, possibly due to their role in the transcription initiation factor TFIID instead of SAGA. We also detected that the Spt8 repressed mutant was extensively invasive in YPD at 300C while a repressed Ngg1 was considerably less invasive compared to its wild type. Also, we have seen that the mutations affecting TBP-binding ability confer susceptibility to drugs, temperature, osmotic, oxidative and DNA damage stress. Further, it seems that the modules of SAGA complex might have antagonistic roles in expression regulation but this needs more in-depth study.

scholarly journals The Role of Transcription Initiation Factor IIIB Subunits in Promoter Opening Probed by Photochemical Cross-linking

2003 ◽  
Vol 278 (20) ◽  
pp. 17912-17917 ◽  
Author(s):  
George A. Kassavetis ◽  
Shulin Han ◽  
Souad Naji ◽  
E. Peter Geiduschek
Keyword(s):  
Transcription Initiation ◽  
Initiation Factor ◽  
Cross Linking ◽  
Transcription Initiation Factor

Molecular cloning, expression, and characterization of the Drosophila 85-kilodalton TFIID subunit

1993 ◽  
Vol 13 (12) ◽  
pp. 7859-7863
Author(s):  
T Kokubo ◽  
D W Gong ◽  
S Yamashita ◽  
R Takada ◽  
R G Roeder ◽  
...  
Keyword(s):  
Transcription Initiation ◽  
Initiation Factor ◽  
Transcriptional Regulatory ◽  
Transcription Initiation Factor ◽  
Multimeric Protein ◽  
And Function ◽  
Tfiid Complex ◽  
Binding Subunit

Transcription initiation factor TFIID is a multimeric protein complex that plays a central role in mediating promoter responses to various activators and repressors. To further understand the role of the 85-kDa TFIID subunit (p85), we have cloned the corresponding cDNA with a probe based on an amino acid sequence of the purified protein. The recombinant p85 interacts directly with both the TATA box-binding subunit (TFIID tau or TBP) and the 110-kDa subunit (p110) of TFIID, suggesting that p85 may play a role in helping to anchor p110 within the TFIID complex and, with other studies, that TFIID assembly and function may involve a concerted series of subunit interactions. Interestingly, the carboxy terminus of p85 contains eight of the WD-40 repeats found originally in the beta subunit of G proteins and more recently in other transcriptional regulatory factors. However, truncated p85 lacking all the WD-40 repeats maintained interactions with both TFIID tau and p110. These observations leave open the possibility of a distinct function for the WD-40 repeats, possibly in transducing signals by interactions with transcriptional regulators and/or other components of the basic transcriptional machinery.

scholarly journals Two RNA Polymerase I Subunits Control the Binding and Release of Rrn3 during Transcription

2007 ◽  
Vol 28 (5) ◽  
pp. 1596-1605 ◽  
Author(s):  
Frédéric Beckouet ◽  
Sylvie Labarre-Mariotte ◽  
Benjamin Albert ◽  
Yukiko Imazawa ◽  
Michel Werner ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Transcription Initiation ◽  
Binding Domain ◽  
Rna Polymerase I ◽  
Initiation Factor ◽  
C Terminus ◽  
Transcription Initiation Factor ◽  
Polymerase I ◽  
Polymerase Mutants

ABSTRACT Rpa34 and Rpa49 are nonessential subunits of RNA polymerase I, conserved in species from Saccharomyces cerevisiae and Schizosaccharomyces pombe to humans. Rpa34 bound an N-terminal region of Rpa49 in a two-hybrid assay and was lost from RNA polymerase in an rpa49 mutant lacking this Rpa34-binding domain, whereas rpa34Δ weakened the binding of Rpa49 to RNA polymerase. rpa34Δ mutants were caffeine sensitive, and the rpa34Δ mutation was lethal in a top1Δ mutant and in rpa14Δ, rpa135(L656P), and rpa135(D395N) RNA polymerase mutants. These defects were shared by rpa49Δ mutants, were suppressed by the overexpression of Rpa49, and thus, were presumably mediated by Rpa49 itself. rpa49 mutants lacking the Rpa34-binding domain behaved essentially like rpa34Δ mutants, but strains carrying rpa49Δ and rpa49-338::HIS3 (encoding a form of Rpa49 lacking the conserved C terminus) had reduced polymerase occupancy at 30°C, failed to grow at 25°C, and were sensitive to 6-azauracil and mycophenolate. Mycophenolate almost fully dissociated the mutant polymerase from its ribosomal DNA (rDNA) template. The rpa49Δ and rpa49-338::HIS3 mutations had a dual effect on the transcription initiation factor Rrn3 (TIF-IA). They partially impaired its recruitment to the rDNA promoter, an effect that was bypassed by an N-terminal deletion of the Rpa43 subunit encoded by rpa43-35,326, and they strongly reduced the release of the Rrn3 initiation factor during elongation. These data suggest a dual role of the Rpa49-Rpa34 dimer during the recruitment of Rrn3 and its subsequent dissociation from the elongating polymerase.

scholarly journals Molecular cloning, expression, and characterization of the Drosophila 85-kilodalton TFIID subunit.

1993 ◽  
Vol 13 (12) ◽  
pp. 7859-7863 ◽  
Author(s):  
T Kokubo ◽  
D W Gong ◽  
S Yamashita ◽  
R Takada ◽  
R G Roeder ◽  
...  
Keyword(s):  
Transcription Initiation ◽  
Initiation Factor ◽  
Transcriptional Regulatory ◽  
Transcription Initiation Factor ◽  
Multimeric Protein ◽  
And Function ◽  
Tfiid Complex ◽  
Binding Subunit

Transcription initiation factor TFIID is a multimeric protein complex that plays a central role in mediating promoter responses to various activators and repressors. To further understand the role of the 85-kDa TFIID subunit (p85), we have cloned the corresponding cDNA with a probe based on an amino acid sequence of the purified protein. The recombinant p85 interacts directly with both the TATA box-binding subunit (TFIID tau or TBP) and the 110-kDa subunit (p110) of TFIID, suggesting that p85 may play a role in helping to anchor p110 within the TFIID complex and, with other studies, that TFIID assembly and function may involve a concerted series of subunit interactions. Interestingly, the carboxy terminus of p85 contains eight of the WD-40 repeats found originally in the beta subunit of G proteins and more recently in other transcriptional regulatory factors. However, truncated p85 lacking all the WD-40 repeats maintained interactions with both TFIID tau and p110. These observations leave open the possibility of a distinct function for the WD-40 repeats, possibly in transducing signals by interactions with transcriptional regulators and/or other components of the basic transcriptional machinery.

TATA box-binding protein (TBP) is a constituent of the polymerase I-specific transcription initiation factor TIF-IB (SL1) bound to the rRNA promoter and shows differential sensitivity to TBP-directed reagents in polymerase I, II, and III transcription factors

1994 ◽  
Vol 14 (1) ◽  
pp. 597-605
Author(s):  
C A Radebaugh ◽  
J L Matthews ◽  
G K Geiss ◽  
F Liu ◽  
J M Wong ◽  
...  
Keyword(s):  
Transcription Initiation ◽  
Binding Protein ◽  
Acanthamoeba Castellanii ◽  
Differential Sensitivity ◽  
Initiation Factor ◽  
Transcription Initiation Factor ◽  
I Factor ◽  
Tata Box Binding Protein ◽  
Polymerase I

The role of the Acanthamoeba castellanii TATA-binding protein (TBP) in transcription was examined. Specific antibodies against the nonconserved N-terminal domain of TBP were used to verify the presence of TBP in the fundamental transcription initiation factor for RNA polymerase I, TIF-IB, and to demonstrate that TBP is part of the committed initiation complex on the rRNA promoter. The same antibodies inhibit transcription in all three polymerase systems, but they do so differentially. Oligonucleotide competitors were used to evaluate the accessibility of the TATA-binding site in TIF-IB, TFIID, and TFIIIB. The results suggest that insertion of TBP into the polymerase II and III factors is more similar than insertion into the polymerase I factor.

scholarly journals DOT1L complex regulates transcriptional initiation in human erythroleukemic cells

2021 ◽  
Vol 118 (27) ◽  
pp. e2106148118
Author(s):  
Aiwei Wu ◽  
Junhong Zhi ◽  
Tian Tian ◽  
Ali Cihan ◽  
Murat A. Cevher ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
Transcription Initiation ◽  
Target Genes ◽  
Initiation Factor ◽  
Transcriptional Elongation ◽  
Saga Complex ◽  
Transcriptional Initiation ◽  
Pol Ii ◽  
Transcription Initiation Factor ◽  
Erythroleukemic Cells

DOT1L, the only H3K79 methyltransferase in human cells and a homolog of the yeast Dot1, normally forms a complex with AF10, AF17, and ENL or AF9, is dysregulated in most cases of mixed-lineage leukemia (MLLr), and has been believed to regulate transcriptional elongation on the basis of its colocalization with RNA polymerase II (Pol II), the sharing of subunits (AF9 and ENL) between the DOT1L and super elongation complexes, and the distribution of H3K79 methylation on both promoters and transcribed regions of active genes. Here we show that DOT1L depletion in erythroleukemic cells reduces its global occupancy without affecting the traveling ratio or the elongation rate (assessed by 4sUDRB-seq) of Pol II, suggesting that DOT1L does not play a major role in elongation in these cells. In contrast, analyses of transcription initiation factor binding reveal that DOT1L and ENL depletions each result in reduced TATA binding protein (TBP) occupancies on thousands of genes. More importantly, DOT1L and ENL depletions concomitantly reduce TBP and Pol II occupancies on a significant fraction of direct (DOT1L-bound) target genes, indicating a role for the DOT1L complex in transcription initiation. Mechanistically, proteomic and biochemical studies suggest that the DOT1L complex may regulate transcriptional initiation by facilitating the recruitment or stabilization of transcription factor IID, likely in a monoubiquitinated H2B (H2Bub1)-enhanced manner. Additional studies show that DOT1L enhances H2Bub1 levels by limiting recruitment of the Spt-Ada-Gcn5-acetyltransferase (SAGA) complex. These results advance our understanding of roles of the DOT1L complex in transcriptional regulation and have important implications for MLLr leukemias.

scholarly journals TATA box-binding protein (TBP) is a constituent of the polymerase I-specific transcription initiation factor TIF-IB (SL1) bound to the rRNA promoter and shows differential sensitivity to TBP-directed reagents in polymerase I, II, and III transcription factors.

1994 ◽  
Vol 14 (1) ◽  
pp. 597-605 ◽  
Author(s):  
C A Radebaugh ◽  
J L Matthews ◽  
G K Geiss ◽  
F Liu ◽  
J M Wong ◽  
...  
Keyword(s):  
Transcription Initiation ◽  
Binding Protein ◽  
Acanthamoeba Castellanii ◽  
Differential Sensitivity ◽  
Initiation Factor ◽  
Transcription Initiation Factor ◽  
I Factor ◽  
Tata Box Binding Protein ◽  
Polymerase I

The role of the Acanthamoeba castellanii TATA-binding protein (TBP) in transcription was examined. Specific antibodies against the nonconserved N-terminal domain of TBP were used to verify the presence of TBP in the fundamental transcription initiation factor for RNA polymerase I, TIF-IB, and to demonstrate that TBP is part of the committed initiation complex on the rRNA promoter. The same antibodies inhibit transcription in all three polymerase systems, but they do so differentially. Oligonucleotide competitors were used to evaluate the accessibility of the TATA-binding site in TIF-IB, TFIID, and TFIIIB. The results suggest that insertion of TBP into the polymerase II and III factors is more similar than insertion into the polymerase I factor.

scholarly journals Inhibition of TATA Binding Protein Dimerization by RNA Polymerase III Transcription Initiation Factor Brf1

2004 ◽  
Vol 279 (31) ◽  
pp. 32401-32406 ◽  
Author(s):  
Diane E. Alexander ◽  
David J. Kaczorowski ◽  
Amy J. Jackson-Fisher ◽  
Drew M. Lowery ◽  
Sara J. Zanton ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Transcription Initiation ◽  
Binding Protein ◽  
Rna Polymerase Iii ◽  
Tata Binding Protein ◽  
Initiation Factor ◽  
Protein Dimerization ◽  
Polymerase Iii ◽  
Transcription Initiation Factor
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