scholarly journals Minigene as a Novel Regulatory Element in Toxin-Antitoxin Systems

2021 ◽  
Vol 22 (24) ◽  
pp. 13389
Author(s):  
Barbara Kędzierska ◽  
Katarzyna Potrykus
Keyword(s):  
Regulatory Mechanism ◽  
Gene Expression Regulation ◽  
Regulatory Element ◽  
Critical Parameters ◽  
Gene Fusions ◽  
Type Ii ◽  
Tight Control ◽  
Genetic Studies ◽  
Reading Frame ◽  
In Cis

The axe-txe type II toxin-antitoxin (TA) system is characterized by a complex and multilayered mode of gene expression regulation. Precise and tight control of this process is crucial to keep the toxin in an appropriate balance with the cognate antitoxin until its activation is needed for the cell. In this report, we provide evidence that a minigene encoded within the axe-txe operon influences translation of the Txe toxin. This is the first example to date of such a regulatory mechanism identified in the TA modules. Here, in a series of genetic studies, we employed translational reporter gene fusions to establish the molecular basis of this phenomenon. Our results show that translation of the two-codon mini-ORF displays an in cis mode of action, and positively affects the expression of txe, possibly by increasing its mRNA stability through protection from an endonuclease attack. Moreover, we established that the reading frame in which the two cistrons are encoded, as well as the distance between them, are critical parameters that affect the level of such regulation. In addition, by searching for two-codon ORFs we found sequences of several potential minigenes in the leader sequences of several other toxins belonging to the type II TA family. These findings suggest that this type of gene regulation may not only apply for the axe-txe cassette, but could be more widespread among other TA systems.

Autoimmunity and Frontotemporal Dementia

2018 ◽  
Vol 15 (7) ◽  
pp. 602-609 ◽  
Author(s):  
Antonella Alberici ◽  
Viviana Cristillo ◽  
Stefano Gazzina ◽  
Alberto Benussi ◽  
Alessandro Padovani ◽  
...  
Keyword(s):  
Frontotemporal Dementia ◽  
Language Impairment ◽  
Neurodegenerative Disorder ◽  
Chromosome 9 ◽  
Bibliographic Databases ◽  
Extensive Literature ◽  
Genetic Studies ◽  
Reading Frame ◽  
Current State ◽  
Extensive Evaluation

Background: Frontotemporal Dementia (FTD) is a neurodegenerative disorder which asymmetrically affects the frontotemporal lobe, characterized by behavioural abnormalities, language impairment, and deficits of executive functions. Genetic studies identified mutations causing the disease, namely Microtubule Associated Protein Tau (MAPT), Granulin (GRN) and chromosome 9 open reading frame 72 (C9orf72) mutations, which contributed to elucidate the molecular pathways involved in brain depositions of either Tau or TAR DNA-binding protein 43 (TDP43) inclusions. However, in the majority of sporadic FTD patients, the mechanisms triggering Tau or TDP43 protein deposition are still to be uncovered. Objective: We aimed to present an extensive evaluation of literature data on immune homeostasis in FTD, in order to provide potentially evidence-based approaches for a disease still orphan of any treatment. Methods: A structured search of bibliographic databases from peer-reviewed literature was pursued focusing on autoimmunity in the brain and FTD. Results: One-hundred-fourteen papers were included in this review. The majority of studies (32) were represented by extensive literature revision on immunity, central nervous system (CNS) and autoimmunity; neuroimaging papers (11) in autoimmune diseases were evaluated, and immunomodulatory approaches (25) were revised. Six papers were found specifically related to FTD and autoimmune hypothesis, the other papers referring to current state of art on FTD. Conclusion: Overall this review contribute to expand the knowledge of a possible immune hypothesis in FTD, suggesting therapeutic perspectives in autoimmune related neurodegeneration, to reduce or revert the disease.

Transvection and Silencing of the Scr Homeotic Gene of Drosophila melanogaster

Genetics ◽  
2002 ◽  
Vol 161 (2) ◽  
pp. 733-746
Author(s):  
Jeffrey W Southworth ◽  
James A Kennison
Keyword(s):  
Drosophila Melanogaster ◽  
Chromosomal Aberrations ◽  
Regulatory Element ◽  
Regulatory Elements ◽  
Anomalous Behavior ◽  
Polycomb Group ◽  
Homeotic Gene ◽  
Polycomb Group Proteins ◽  
Sex Combs Reduced ◽  
In Cis

Abstract The Sex combs reduced (Scr) gene specifies the identities of the labial and first thoracic segments in Drosophila melanogaster. In imaginal cells, some Scr mutations allow cis-regulatory elements on one chromosome to stimulate expression of the promoter on the homolog, a phenomenon that was named transvection by Ed Lewis in 1954. Transvection at the Scr gene is blocked by rearrangements that disrupt pairing, but is zeste independent. Silencing of the Scr gene in the second and third thoracic segments, which requires the Polycomb group proteins, is disrupted by most chromosomal aberrations within the Scr gene. Some chromosomal aberrations completely derepress Scr even in the presence of normal levels of all Polycomb group proteins. On the basis of the pattern of chromosomal aberrations that disrupt Scr gene silencing, we propose a model in which two cis-regulatory elements interact to stabilize silencing of any promoter or cis-regulatory element physically between them. This model also explains the anomalous behavior of the Scx allele of the flanking homeotic gene, Antennapedia. This allele, which is associated with an insertion near the Antennapedia P1 promoter, inactivates the Antennapedia P1 and P2 promoters in cis and derepresses the Scr promoters both in cis and on the homologous chromosome.

scholarly journals An unusual genomic position effect on Drosophila white gene expression: pairing dependence, interactions with zeste, and molecular analysis of revertants.

Genetics ◽  
1992 ◽  
Vol 130 (1) ◽  
pp. 125-138 ◽  
Author(s):  
T Hazelrigg ◽  
S Petersen
Keyword(s):  
Gene Expression ◽  
Regulatory Element ◽  
Position Effect ◽  
Insertion Site ◽  
White Gene ◽  
Chromosome 2 ◽  
Wild Type ◽  
Gene Copies ◽  
In Trans ◽  
In Cis

Abstract The white gene in the AR4-24 P[white,rosy] insertion on chromosome 2 has a novel expression pattern, in which it is repressed in the dorsal half of the eye. X-ray mutagenesis led to the isolation of six revertants mapping to chromosome 2, which are wild type in a zeste+ background, and three extreme derivatives, in which white gene expression is repressed in ventral regions of the eye as well. By Southern blot analyses the breakpoints of five of the revertants and one of the extreme derivatives were mapped in the flanking DNA bordering each side of the AR4-24 insertion. The revertants show some dorsal repression of white in the presence of z1, and by this criterion each is only a partial revertant. The extreme derivatives act not only in cis, but also in trans to repress expression of AR4-24 and its various derivatives. We provide evidence that these trans effects are proximity-dependent effects, possibly mediated by pairing of gene copies, as they do not extend to copies of the white gene located elsewhere in the genome. We show that one extreme derivative, E1, is a small deletion spanning the insertion site at the 5' end of the white gene, and propose that the distance between a negative regulatory element in the 5' flanking DNA and the white promoter influences the degree of the repression.

scholarly journals Towards Exploring Toxin-Antitoxin Systems in Geobacillus: A Screen for Type II Toxin-Antitoxin System Families in a Thermophilic Genus

2019 ◽  
Vol 20 (23) ◽  
pp. 5869 ◽  
Author(s):  
Rawana Alkhalili ◽  
Joel Wallenius ◽  
Björn Canbäck
Keyword(s):  
Gene Expression ◽  
Experimental Research ◽  
Gene Order ◽  
Stress Responses ◽  
Gene Expression Regulation ◽  
Protein Domain ◽  
Limited Attention ◽  
Type Ii ◽  
Biotechnological Potential ◽  
Ncbi Blast

The toxin-antitoxin (TA) systems have been attracting attention due to their role in regulating stress responses in prokaryotes and their biotechnological potential. Much recognition has been given to type II TA system of mesophiles, while thermophiles have received merely limited attention. Here, we are presenting the putative type II TA families encoded on the genomes of four Geobacillus strains. We employed the TA finder tool to mine for TA-coding genes and manually curated the results using protein domain analysis tools. We also used the NCBI BLAST, Operon Mapper, ProOpDB, and sequence alignment tools to reveal the geobacilli TA features. We identified 28 putative TA pairs, distributed over eight TA families. Among the identified TAs, 15 represent putative novel toxins and antitoxins, belonging to the MazEF, MNT-HEPN, ParDE, RelBE, and XRE-COG2856 TA families. We also identified a potentially new TA composite, AbrB-ParE. Furthermore, we are suggesting the Geobacillus acetyltransferase TA (GacTA) family, which potentially represents one of the unique TA families with a reverse gene order. Moreover, we are proposing a hypothesis on the xre-cog2856 gene expression regulation, which seems to involve the c-di-AMP. This study aims for highlighting the significance of studying TAs in Geobacillus and facilitating future experimental research.

scholarly journals An Alternative Platform for Protein Expression Using an Innate Whole Expression Module from Metagenomic DNA

2019 ◽  
Vol 7 (1) ◽  
pp. 9 ◽  
Author(s):  
Dae-Eun Cheong ◽  
So-Youn Park ◽  
Ho-Dong Lim ◽  
Geun-Joong Kim
Keyword(s):  
Gene Expression ◽  
Regulatory Element ◽  
Expression System ◽  
Expression Patterns ◽  
Gene Clusters ◽  
Single Element ◽  
Reading Frame ◽  
Cis Acting ◽  
Dna Libraries ◽  
Expression Module

Many integrated gene clusters beyond a single genetic element are commonly trapped as the result of promoter traps in (meta)genomic DNA libraries. Generally, a single element, which is mainly the promoter, is deduced from the resulting gene clusters and employed to construct a new expression vector. However, expression patterns of target proteins under the incorporated promoter are often inconsistent with those shown in clones harboring plasmids with gene clusters. These results suggest that the integrated set of gene clusters with diverse cis- and trans-acting elements is evolutionarily tuned as a complete set for gene expression, and is an expression module with all the components for the expression of a nested open reading frame (ORF). This possibility is further supported by truncation and/or serial deletion analysis of this module in which the expression of the nested ORF is highly fluctuated or reduced frequently, despite being supported by plentiful cis-acting elements in the spanning regions around the ORF such as the promoter, ribosome binding site (RBS), terminator, and 3′-/5′-UTRs for gene expression. Here, we examined whether an innate module with a naturally overexpressed gene could be considered as a scaffold for an expression system. For a proof-of-principle study, we mined a complete expression module with an innately overexpressed ORF in E. coli from a metagenomics DNA library, and incorporated it into a vector that had no regulatory element for expressing the insert. We obtained successful expression of several inserts such as MBP, GFPuv, β-glucosidase, and esterase using this simple construct without tuning and codon optimization of the target insert.

scholarly journals The Role of Insulation in Patterning Gene Expression

Genes ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 767 ◽  
Author(s):  
Özdemir ◽  
Gambetta
Keyword(s):  
Regulatory Element ◽  
Gene Promoter ◽  
Regulatory Elements ◽  
Spatial And Temporal Patterns ◽  
Genetic Studies ◽  
Animal Development ◽  
Binding Factor ◽  
Dna Elements ◽  
Biochemical Analyses

Development is orchestrated by regulatory elements that turn genes ON or OFF in precise spatial and temporal patterns. Many safety mechanisms prevent inappropriate action of a regulatory element on the wrong gene promoter. In flies and mammals, dedicated DNA elements (insulators) recruit protein factors (insulator binding proteins, or IBPs) to shield promoters from regulatory elements. In mammals, a single IBP called CCCTC-binding factor (CTCF) is known, whereas genetic and biochemical analyses in Drosophila have identified a larger repertoire of IBPs. How insulators function at the molecular level is not fully understood, but it is currently thought that they fold chromosomes into conformations that affect regulatory element-promoter communication. Here, we review the discovery of insulators and describe their properties. We discuss recent genetic studies in flies and mice to address the question: Is gene insulation important for animal development? Comparing and contrasting observations in these two species reveal that they have different requirements for insulation, but that insulation is a conserved and critical gene regulation strategy.

scholarly journals Late-onset presentation of POLG1-associated mitochondrial disease

2019 ◽  
Vol 12 (3) ◽  
pp. e228482 ◽  
Author(s):  
Bruna Meira ◽  
Rafael Roque ◽  
Miguel Pinto ◽  
André Caetano
Keyword(s):  
Mitochondrial Disease ◽  
Age Of Onset ◽  
Late Onset ◽  
Clinical Manifestations ◽  
Progressive External Ophthalmoplegia ◽  
Clinical Feature ◽  
Gait Ataxia ◽  
Chronic Progressive External Ophthalmoplegia ◽  
Genetic Studies ◽  
In Cis

Mutations in the nuclear POLG1 gene compromise the integrity of mitochondrial DNA and show great allelic and clinical heterogeneity. Among adult POLG1-associated mitochondrial disease, the main clinical feature is chronic progressive external ophthalmoplegia. Other related clinical manifestations are sensory or cerebellar ataxia, peripheral neuropathy, myopathy or extrapyramidal symptoms. We report the case of a 72-year-old man who presented with a late onset sensory neuronopathy, chronic progressive external ophthalmoplegia, gait ataxia and parkinsonism. Genetic studies showed a compound heterozygosity of known pathogenic mutations in the POLG1 gene (variant T252I/P587 L in cis configuration in allele 1 and variant R807C in allele 2). Late life presentation highlights that mitochondrial disorders should be considered regardless of age of onset of symptoms.

scholarly journals Type II Isopentenyl Diphosphate Isomerase from Synechocystis sp. Strain PCC 6803

2004 ◽  
Vol 186 (23) ◽  
pp. 8156-8158 ◽  
Author(s):  
Sam J. Barkley ◽  
Shrivallabh B. Desai ◽  
C. Dale Poulter
Keyword(s):  
Escherichia Coli ◽  
Open Reading Frame ◽  
Flavin Mononucleotide ◽  
Isopentenyl Diphosphate ◽  
Type Ii ◽  
Isopentenyl Diphosphate Isomerase ◽  
Reading Frame ◽  
Synechocystis Sp ◽  
Pcc 6803

ABSTRACT Open reading frame sll1556 in the cyanobacterium Synechocystis sp. strain 6803 encodes a putative type II isopentenyl diphosphate (IPP) isomerase. The His6-tagged protein was produced in Escherichia coli and purified by Ni2+ chromatography. The homotetrameric enzyme required NADPH, flavin mononucleotide, and Mg2+ for activity; K m IPP was 52 μM, and k cat IPP was 0.23 s−1.

scholarly journals RNR-R2 Upregulation by a Short Non-Coding Viral Transcript

Biomolecules ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1822
Author(s):  
Karin Broennimann ◽  
Inna Ricardo-Lax ◽  
Julia Adler ◽  
Eleftherios Michailidis ◽  
Ype P. de Jong ◽  
...  
Keyword(s):  
Dna Damage Response ◽  
Regulatory Element ◽  
Human Hepatocytes ◽  
Viral Transcript ◽  
Dna Viruses ◽  
Reading Frame ◽  
Intracellular Dntp ◽  
B Virus ◽  
Damage Response ◽  
Dividing Cells

DNA viruses require dNTPs for replication and have developed different strategies to increase intracellular dNTP pools. Hepatitis B virus (HBV) infects non-dividing cells in which dNTPs are scarce and the question is how viral replication takes place. Previously we reported that the virus induces the DNA damage response (DDR) pathway culminating in RNR-R2 expression and the generation of an active RNR holoenzyme, the key regulator of dNTP levels, leading to an increase in dNTPs. How the virus induces DDR and RNR-R2 upregulation is not completely known. The viral HBx open reading frame (ORF) was believed to trigger this pathway. Unexpectedly, however, we report here that the production of HBx protein is dispensable. We found that a small conserved region of 125 bases within the HBx ORF is sufficient to upregulate RNR-R2 expression in growth-arrested HepG2 cells and primary human hepatocytes. The observed HBV mRNA embedded regulatory element is named ERE. ERE in isolation is sufficient to activate the ATR-Chk1-E2F1-RNR-R2 DDR pathway. These findings demonstrate a non-coding function of HBV transcripts to support its propagation in non-cycling cells.

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