scholarly journals SarA of Staphylococcus aureus Binds to the sarA Promoter To Regulate Gene Expression

2008 ◽  
Vol 190 (6) ◽  
pp. 2239-2243 ◽  
Author(s):  
Ambrose L. Cheung ◽  
Koren Nishina ◽  
Adhar C. Manna

ABSTRACT The 375-bp sarA open reading frame is driven by three promoters, P1, P3, and P2. Using gel shift and DNase I footprinting assays, we found that SarA binds to two 26-bp sequences and one 31-bp sequence within the P1 and P3 promoters, respectively. Together with the results of transcription analyses, our data indicate that SarA binds to its own promoter to down-regulate sarA expression.

2017 ◽  
Author(s):  
Miquel Angel Schikora-Tamarit ◽  
Guillem Lopez-Grado i Salinas ◽  
Carolina Gonzalez Navasa ◽  
Irene Calderon ◽  
Xavi Marcos-Fa ◽  
...  

Cells regulate gene expression by changing the concentration and activity of transcription factors (TFs). The response of each gene to changes in TF activity is generally assumed to be encoded in the promoter. Here we show that, even when the promoter itself remains constant, each gene has a unique TF dose response curve. Many genes have an intrinsic ability to either buffer or amplify the effects of high promoter activity. We present a coupled mathematical model and experimental system for quantifying this property. Promoter activity buffering can be encoded by sequences in both the open reading frame and 3UTR and can be implemented by both autoregulatory feedback loops and by titration of limiting trans regulators. We show experimentally that promoter activity buffering insulates cells from fitness defects due to misexpression. The response of genes to changes in [TF] is encoded by sequences outside of the promoter, and this effect can either insulate or amplify the effects of aneuploidy and misregulation on organismal fitness.


1999 ◽  
Vol 73 (12) ◽  
pp. 10519-10524 ◽  
Author(s):  
Delyth J. Goodwin ◽  
Kersten T. Hall ◽  
Alex J. Stevenson ◽  
Alex F. Markham ◽  
Adrian Whitehouse

ABSTRACT The herpesvirus saimiri open reading frame (ORF) 57 is homologous to genes identified in all classes of herpesviruses. It has previously been shown to regulate gene expression through a posttranscriptional mechanism. We demonstrate in this report that the expression of the ORF 57 protein leads to the cytoplasmic accumulation of glycoprotein B and capsid mRNAs. We also demonstrate that ORF 57 has the ability to specifically bind viral RNA transcripts. Utilizing an interspecies heterokaryon assay, we show that ORF 57 has the ability to shuttle between the nucleus and the cytoplasm. Furthermore, we show that ORF 57 contains a relatively leucine-rich sequence which shares some homology with nuclear export signals (NES) found in a number of proteins with the ability to shuttle between the nucleus and the cytoplasm. Moreover, we demonstrate that the ORF 57 NES enables the nuclear export of a heterologous protein and that mutation of the conserved leucine residues contained within the ORF 57 NES signal abrogates the ability of the ORF 57 protein to shuttle between the nucleus and cytoplasm. These results suggest that ORF 57 is involved in mediating the nuclear export of viral transcripts.


2001 ◽  
Vol 75 (20) ◽  
pp. 10005-10013 ◽  
Author(s):  
Loren del Mar Peña ◽  
Laimonis A. Laimins

ABSTRACT The life cycle of human papillomaviruses (HPVs) is tightly linked to the differentiation status of the host cell. While early genes are expressed during the initial stages of viral infection, late gene expression occurs in the suprabasal layers of the cervical epithelium. Late genes encode E1^E4, a cytosolic protein, and capsid proteins L1 and L2. We have mapped over 30 initiation sites for late transcripts and show that the transcripts initiate in a 200-nucleotide region within the E7 open reading frame. The mechanisms regulating the activation of late gene expression, however, are not yet understood. DNase I hypersensitivity analysis of HPV-31 chromatin in cell lines that maintain viral genomes extrachromosomally indicates that a major shift in nuclease digestion occurs upon differentiation. In undifferentiated cells, hypersensitive regions exist in the upstream regulatory region proximal to the E6 open reading frame. Upon differentiation, a region between nucleotides 659 and 811 in the E7 open reading frame becomes accessible to DNase I. These results indicate that the late transcript initiation region becomes accessible to transcription factor binding upon differentiation. Several complexes mediate chromatin rearrangement, and we tested whether histone acetylation was sufficient for late transcript activation. Treatment with the histone deacetylase inhibitor trichostatin A was found to be insufficient to activate late gene expression in undifferentiated cells. However, it did activate expression of early transcripts. These results suggest that chromatin remodeling around the late promoter occurs upon epithelial differentiation and that mechanisms in addition to histone deacetylation contribute to activation of late gene expression.


2005 ◽  
Vol 73 (7) ◽  
pp. 4391-4394 ◽  
Author(s):  
Ambrose L. Cheung ◽  
Adhar C. Manna

ABSTRACT The global regulatory locus sarA comprises a 375-bp open reading frame that is driven by three promoters, the proximal P1 and distal P3 and P2 promoters. We mutated the weaker P3 and P2 promoters to ascertain the effect of the change on SarA protein and target gene expression. Our results indicated that the solely active P1 promoter led to a lower SarA protein level, which has an effect on agr transcription and subsequently had corresponding effects on hla, sspA, and spa transcription, probably in both agr-independent and agr-dependent manners.


1992 ◽  
Vol 66 (1) ◽  
pp. 95-105 ◽  
Author(s):  
A M Colberg-Poley ◽  
L D Santomenna ◽  
P P Harlow ◽  
P A Benfield ◽  
D J Tenney

2019 ◽  
Vol 70 (19) ◽  
pp. 5355-5374 ◽  
Author(s):  
Dandan Zang ◽  
Jingxin Wang ◽  
Xin Zhang ◽  
Zhujun Liu ◽  
Yucheng Wang

Abstract Plant heat shock transcription factors (HSFs) are involved in heat and other abiotic stress responses. However, their functions in salt tolerance are little known. In this study, we characterized the function of a HSF from Arabidopsis, AtHSFA7b, in salt tolerance. AtHSFA7b is a nuclear protein with transactivation activity. ChIP-seq combined with an RNA-seq assay indicated that AtHSFA7b preferentially binds to a novel cis-acting element, termed the E-box-like motif, to regulate gene expression; it also binds to the heat shock element motif. Under salt conditions, AtHSFA7b regulates its target genes to mediate serial physiological changes, including maintaining cellular ion homeostasis, reducing water loss rate, decreasing reactive oxygen species accumulation, and adjusting osmotic potential, which ultimately leads to improved salt tolerance. Additionally, most cellulose synthase-like (CSL) and cellulose synthase (CESA) family genes were inhibited by AtHSFA7b; some of them were randomly selected for salt tolerance characterization, and they were mainly found to negatively modulate salt tolerance. By contrast, some transcription factors (TFs) were induced by AtHSFA7b; among them, we randomly identified six TFs that positively regulate salt tolerance. Thus, AtHSFA7b serves as a transactivator that positively mediates salinity tolerance mainly through binding to the E-box-like motif to regulate gene expression.


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