Mitochondrial upstream promoter sequences modulate in vivo the transcription of a gene in yeast mitochondria

Mitochondrion ◽  
2006 ◽  
Vol 6 (6) ◽  
pp. 289-298 ◽  
Author(s):  
A. Pfeuty ◽  
C. Dufresne ◽  
M. Gueride ◽  
G. Lecellier
1991 ◽  
Vol 11 (7) ◽  
pp. 3676-3681
Author(s):  
W M Yang ◽  
W Gahl ◽  
D Hamer

The induction of Saccharomyces cerevisiae metallothionein gene transcription by Cu and Ag is mediated by the ACE1 transcription factor. In an effort to detect additional stimuli and factors that regulate metallothionein gene transcription, we isolated a Cu-resistant suppressor mutant of an ACE1 deletion strain. Even in the absence of metals, the suppressor mutant exhibited high basal levels of metallothionein gene transcription that required upstream promoter sequences. The suppressor gene was cloned, and its predicted product was shown to correspond to yeast heat shock transcription factor with a single-amino-acid substitution in the DNA-binding domain. The mutant heat shock factor bound strongly to metallothionein gene upstream promoter sequences, whereas wild-type heat shock factor interacted weakly with the same region. Heat treatment led to a slight but reproducible induction of metallothionein gene expression in both wild-type and suppressor strains, and Cd induced transcription in the mutant strain. These studies provide evidence for multiple pathways of metallothionein gene transcriptional regulation in S. cerevisiae.


1993 ◽  
Vol 13 (7) ◽  
pp. 4167-4173
Author(s):  
J Min ◽  
H P Zassenhaus

An activity from Saccharomyces cerevisiae mitochondria was identified that specifically bound to a 12-nucleotide sequence, AAUAA(U/C)AUUCUU, that is a site for processing of pre-mRNAs so as to generate the mature 3' ends of mRNAs. Because processing occurs 3' to the end of the dodecamer site, all mRNAs in yeast mitochondria terminate with that sequence. RNase T1 digestion fragments which terminated precisely at their 3' ends with the dodecamer sequence bound the activity, indicating that mRNAs in vivo would be capable of binding. Gel mobility shift analyses using RNA oligonucleotides showed that binding was reduced by a U-to-A substitution at position 3 of the dodecamer sequence; a C-to-A substitution at position 10 eliminated binding. UV cross-linking identified three polypeptides with approximate molecular masses of 19, 60, and 70 kDa as constituents of the binding activity. These estimates included the contribution of the 32P-labeled RNA oligonucleotide used to tag these polypeptides. An oligonucleotide with a UA-->AU substitution at positions 3 and 4 of the dodecamer site formed complexes deficient in the 19-kDa species, suggesting that binding specificity was inherent to the higher-molecular-weight polypeptides. Assembly of the complex at a dodecamer site on an RNA protected sequences located 5' to the dodecamer site from digestion by a nucleoside triphosphate-dependent 3' exoribonuclease found in yeast mitochondria. Since mitochondrial mRNAs terminate with an intact dodecamer sequence, the binding activity may function in the stabilization of mRNAs in addition to 3'-end formation of mRNAs.


1988 ◽  
Vol 8 (6) ◽  
pp. 2562-2571
Author(s):  
S Partono ◽  
A S Lewin

The terminal intron of the mitochondrial cob gene of Saccharomyces cerevisiae can undergo autocatalytic splicing in vitro. Efficient splicing of this intron required a high concentration of monovalent ion (1 M). We found that at a high salt concentration this intron was very active and performed many of the reactions described for other group I introns. The rate of the splicing reaction was dependent on the choice of the monovalent ion; the reaction intermediate, the intron-3' exon molecule, accumulated in NH4Cl but not in KCl. In addition, the intron was more reactive in KCl, accumulating in two different circular forms: one cyclized at the 5' intron boundary and the other at 236 nucleotides from the 5' end. These circular forms were able to undergo the opening and recyclization reactions previously described for the Tetrahymena rRNA intron. Cleavage of the 5' exon-intron boundary by the addition of GTP did not require the 3' terminus of the intron and the downstream exon. An anomalous guanosine addition at the 3' exon and at the middle of the intron was also detected. Hence, this intron, which requires a functional protein to splice in vivo, demonstrated a full spectrum of characteristic reactions in the absence of proteins.


1984 ◽  
Vol 4 (1) ◽  
pp. 133-141
Author(s):  
J Brady ◽  
M Radonovich ◽  
M Thoren ◽  
G Das ◽  
N P Salzman

We have previously identified an 11-base DNA sequence, 5'-G-G-T-A-C-C-T-A-A-C-C-3' (simian virus 40 [SV40] map position 294 to 304), which is important in the control of SV40 late RNA expression in vitro and in vivo (Brady et al., Cell 31:625-633, 1982). We report here the identification of another domain of the SV40 late promoter. A series of mutants with deletions extending from SV40 map position 0 to 300 was prepared by nuclease BAL 31 treatment. The cloned templates were then analyzed for efficiency and accuracy of late SV40 RNA expression in the Manley in vitro transcription system. Our studies showed that, in addition to the promoter domain near map position 300, there are essential DNA sequences between nucleotide positions 74 and 95 that are required for efficient expression of late SV40 RNA. Included in this SV40 DNA sequence were two of the six GGGCGG SV40 repeat sequences and an 11-nucleotide segment which showed strong homology with the upstream sequences required for the efficient in vitro and in vivo expression of the histone H2A gene. This upstream promoter sequence supported transcription with the same efficiency even when it was moved 72 nucleotides closer to the major late cap site. In vitro promoter competition analysis demonstrated that the upstream promoter sequence, independent of the 294 to 304 promoter element, is capable of binding polymerase-transcription factors required for SV40 late gene transcription. Finally, we show that DNA sequences which control the specificity of RNA initiation at nucleotide 325 lie downstream of map position 294.


Author(s):  
M Nevin ◽  
X Song ◽  
S Japoni ◽  
J Zagozewski ◽  
Q Jiang ◽  
...  

Introduction: Diffuse intrinsic pontine glioma (DIPG) is refractory to therapy. The identification of histone H3.1/H3.3 K27M mutations in most DIPG has provided new insights. The DLX homeobox genes are expressed in the developing forebrain. The Dlx1/Dlx2 double knockout (DKO) mouse loses tangential GABAergic interneuron migration to the neocortex. We have identified genes that encode glutamic acid decarboxylase (GAD) enzymes as direct targets of DLX1/DLX2. In DIPG patients with H3.3 K27M mutations there is decreased Dlx2 and increased expression of the myelin transcription factor, Myt1. Methods and Results: We used bioinformatics approaches and chromatin immunoprecipitation (ChIP) assays to identify Olig2, Nkx2.2 and Myt1 promoter sequences as candidate DLX2 targets in vivo. DNA binding specificity was confirmed. The functional consequences of Dlx2 co-expression with reporter constructs of ChIP-isolated promoter fragments of Olig2 and Nkx2.2 demonstrated repression of gene targets in vitro. qPCR showed increased Olig2 and Nkx2.2 expression in the DKO forebrain. Stable transfection of a murine DIPG cell line with Dlx2 resulted in increased Gad1 and Gad2 and decreased Olig2 and Nkx2.2 expression. Of significance, we demonstrated decreased expression of H3.3 K27M and restoration of H3.3 K27 tri-methylation (me3). Conclusions: DLX transcription factors promote GABAergic interneuron and concomitant inhibition of oligodendroglial differentiation in neural progenitors by repression of a suite of genes including Olig2 and Nkx2.2. Restoration of H3 K27me3 expression in DIPG provides a promising lead towards exploration of differentiation as a therapeutic strategy for DIPG.


2008 ◽  
Vol 2008 ◽  
pp. 1-9 ◽  
Author(s):  
J. Sunil Rao ◽  
Suresh Karanam ◽  
Colleen D. McCabe ◽  
Carlos S. Moreno

Background. The computational identification of functional transcription factor binding sites (TFBSs) remains a major challenge of computational biology. Results. We have analyzed the conserved promoter sequences for the complete set of human RefSeq genes using our conserved transcription factor binding site (CONFAC) software. CONFAC identified 16296 human-mouse ortholog gene pairs, and of those pairs, 9107 genes contained conserved TFBS in the 3 kb proximal promoter and first intron. To attempt to predict in vivo occupancy of transcription factor binding sites, we developed a novel marginal effect isolator algorithm that builds upon Bayesian methods for multigroup TFBS filtering and predicted the in vivo occupancy of two transcription factors with an overall accuracy of 84%. Conclusion. Our analyses show that integration of chromatin immunoprecipitation data with conserved TFBS analysis can be used to generate accurate predictions of functional TFBS. They also show that TFBS cooccurrence can be used to predict transcription factor binding to promoters in vivo.


EMBO Reports ◽  
2007 ◽  
Vol 8 (3) ◽  
pp. 271-278 ◽  
Author(s):  
Sara Cellai ◽  
Laura Mangiarotti ◽  
Nicola Vannini ◽  
Nikolai Naryshkin ◽  
Ekaterine Kortkhonjia ◽  
...  

2005 ◽  
Vol 187 (20) ◽  
pp. 7062-7071 ◽  
Author(s):  
Mi-Young Hahn ◽  
Sahadevan Raman ◽  
Mauricio Anaya ◽  
Robert N. Husson

ABSTRACT Mycobacterium tuberculosis sigL encodes an extracytoplasmic function (ECF) sigma factor and is adjacent to a gene for a membrane protein (Rv0736) that contains a conserved HXXXCXXC sequence. This motif is found in anti-sigma factors that regulate several ECF sigma factors, including those that control oxidative stress responses. In this work, SigL and Rv0736 were found to be cotranscribed, and the intracellular domain of Rv0736 was shown to interact specifically with SigL, suggesting that Rv0736 may encode an anti-sigma factor of SigL. An M. tuberculosis sigL mutant was not more susceptible than the parental strain to several oxidative and nitrosative stresses, and sigL expression was not increased in response to these stresses. In vivo, sigL is expressed from a weak SigL-independent promoter and also from a second SigL-dependent promoter. To identify SigL-regulated genes, sigL was overexpressed and microarray analysis of global transcription was performed. Four small operons, sigL (Rv0735)-Rv0736, mpt53 (Rv2878c)-Rv2877c, pks10 (Rv1660)-pks7 (Rv1661), and Rv1139c-Rv1138c, were among the most highly upregulated genes in the sigL-overexpressing strain. SigL-dependent transcription start sites of these operons were mapped, and the consensus promoter sequences TGAACC in the −35 region and CGTgtc in the −10 region were identified. In vitro, purified SigL specifically initiated transcription from the promoters of sigL, mpt53, and pks10. Additional genes, including four PE_PGRS genes, appear to be regulated indirectly by SigL. In an in vivo murine infection model, the sigL mutant strain showed marked attenuation, indicating that the sigL regulon is important in M. tuberculosis pathogenesis.


Microbiology ◽  
2005 ◽  
Vol 151 (6) ◽  
pp. 1729-1740 ◽  
Author(s):  
Deborah M. Hinton ◽  
Suchira Pande ◽  
Neelowfar Wais ◽  
Xanthia B. Johnson ◽  
Madhavi Vuthoori ◽  
...  

Activation of bacteriophage T4 middle promoters, which occurs about 1 min after infection, uses two phage-encoded factors that change the promoter specificity of the host RNA polymerase. These phage factors, the MotA activator and the AsiA co-activator, interact with the σ 70 specificity subunit of Escherichia coli RNA polymerase, which normally contacts the −10 and −35 regions of host promoter DNA. Like host promoters, T4 middle promoters have a good match to the canonical σ 70 DNA element located in the −10 region. However, instead of the σ 70 DNA recognition element in the promoter's −35 region, they have a 9 bp sequence (a MotA box) centred at −30, which is bound by MotA. Recent work has begun to provide information about the MotA/AsiA system at a detailed molecular level. Accumulated evidence suggests that the presence of MotA and AsiA reconfigures protein–DNA contacts in the upstream promoter sequences, without significantly affecting the contacts of σ 70 with the −10 region. This type of activation, which is called ‘σ appropriation’, is fundamentally different from other well-characterized models of prokaryotic activation in which an activator frequently serves to force σ 70 to contact a less than ideal −35 DNA element. This review summarizes the interactions of AsiA and MotA with σ 70, and discusses how these interactions accomplish the switch to T4 middle promoters by inhibiting the typical contacts of the C-terminal region of σ 70, region 4, with the host −35 DNA element and with other subunits of polymerase.


2006 ◽  
Vol 173 (1) ◽  
pp. 83-93 ◽  
Author(s):  
Daniela Dorner ◽  
Sylvia Vlcek ◽  
Nicole Foeger ◽  
Andreas Gajewski ◽  
Christian Makolm ◽  
...  

Lamina-associated polypeptide (LAP) 2α is a nonmembrane-bound LAP2 isoform that forms complexes with nucleoplasmic A-type lamins. In this study, we show that the overexpression of LAP2α in fibroblasts reduced proliferation and delayed entry into the cell cycle from a G0 arrest. In contrast, stable down-regulation of LAP2α by RNA interference accelerated proliferation and interfered with cell cycle exit upon serum starvation. The LAP2α-linked cell cycle phenotype is mediated by the retinoblastoma (Rb) protein because the LAP2α COOH terminus directly bound Rb, and overexpressed LAP2α inhibited E2F/Rb-dependent reporter gene activity in G1 phase in an Rb-dependent manner. Furthermore, LAP2α associated with promoter sequences in endogenous E2F/Rb-dependent target genes in vivo and negatively affected their expression. In addition, the expression of LAP2α in proliferating preadipocytes caused the accumulation of hypophosphorylated Rb, which is reminiscent of noncycling cells, and initiated partial differentiation into adipocytes. The effects of LAP2α on cell cycle progression and differentiation may be highly relevant for the cell- and tissue-specific phenotypes observed in laminopathic diseases.


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