scholarly journals Mutational Analysis of the Antitoxin in the Lactococcal Type III Toxin-Antitoxin System AbiQ

2015 ◽  
Vol 81 (11) ◽  
pp. 3848-3855 ◽  
Author(s):  
Maxime Bélanger ◽  
Sylvain Moineau
Keyword(s):  
Noncoding Rna ◽  
Mutational Analysis ◽  
Point Mutations ◽  
Northern Hybridization ◽  
Type Iii ◽  
Infection Mechanism ◽  
Digestion Profile ◽  
Rapid Amplification ◽  
Antiphage Activity

ABSTRACTThe lactococcal abortive phage infection mechanism AbiQ recently was classified as a type III toxin-antitoxin system in which the toxic protein (ABIQ) is regulated following cleavage of its repeated noncoding RNA antitoxin (antiQ). In this study, we investigated the role of the antitoxin in antiphage activity. The cleavage ofantiQby ABIQ was characterized using 5′ rapid amplification of cDNA ends PCR and was located in an adenine-rich region ofantiQ. We next generated a series of derivatives with point mutations withinantiQor with various numbers ofantiQrepetitions. These modifications were analyzed for their effect on the antiphage activity (efficiency of plaquing) and on the endoribonuclease activity (Northern hybridization). We observed that increasing or reducing the number ofantiQrepeats significantly decreased the antiphage activity of the system. Several point mutations had a similar effect on the antiphage activity and were associated with changes in the digestion profile ofantiQ. Interestingly, a point mutation in the putative pseudoknot structure ofantiQmutants led to an increased AbiQ antiphage activity, thereby offering a novel way to increase the activity of an abortive infection mechanism.

scholarly journals Inactivation of BK Channels by the NH2 Terminus of the β2 Auxiliary Subunit: An Essential Role of a Terminal Peptide Segment of Three Hydrophobic Residues

2003 ◽  
Vol 121 (2) ◽  
pp. 125-148 ◽  
Author(s):  
Xiao-Ming Xia ◽  
J.P. Ding ◽  
Christopher J. Lingle
Keyword(s):  
Mutational Analysis ◽  
Point Mutations ◽  
Bk Channels ◽  
Amino Acid Sequences ◽  
Transmembrane Segment ◽  
Critical Determinant ◽  
Specific Distribution ◽  
Voltage Dependent ◽  
Inactivation Process

An auxiliary β2 subunit, when coexpressed with Slo α subunits, produces inactivation of the resulting large-conductance, Ca2+ and voltage-dependent K+ (BK-type) channels. Inactivation is mediated by the cytosolic NH2 terminus of the β2 subunit. To understand the structural requirements for inactivation, we have done a mutational analysis of the role of the NH2 terminus in the inactivation process. The β2 NH2 terminus contains 46 residues thought to be cytosolic to the first transmembrane segment (TM1). Here, we address two issues. First, we define the key segment of residues that mediates inactivation. Second, we examine the role of the linker between the inactivation segment and TM1. The results show that the critical determinant for inactivation is an initial segment of three amino acids (residues 2–4: FIW) after the initiation methionine. Deletions that scan positions from residue 5 through residue 36 alter inactivation, but do not abolish it. In contrast, deletion of FIW or combinations of point mutations within the FIW triplet abolish inactivation. Mutational analysis of the three initial residues argues that inactivation does not result from a well-defined structure formed by this epitope. Inactivation may be better explained by linear entry of the NH2-terminal peptide segment into the permeation pathway with residue hydrophobicity and size influencing the onset and recovery from inactivation. Examination of the ability of artificial, polymeric linkers to support inactivation suggests that a variety of amino acid sequences can serve as adequate linkers as long as they contain a minimum of 12 residues between the first transmembrane segment and the FIW triplet. Thus, neither a specific distribution of charge on the linker nor a specific structure in the linker is required to support the inactivation process.

A Mutational Analysis of dishevelled in Drosophila Defines Novel Domains in the Dishevelled Protein as Well as Novel Suppressing Alleles of axin

Genetics ◽  
2002 ◽  
Vol 161 (2) ◽  
pp. 747-762
Author(s):  
Andrea Penton ◽  
Andreas Wodarz ◽  
Roel Nusse
Keyword(s):  
Planar Cell Polarity ◽  
Mutational Analysis ◽  
Consensus Sequence ◽  
Point Mutations ◽  
Site Directed Mutagenesis ◽  
Missense Mutations ◽  
Genetic Screens ◽  
Planar Polarity ◽  
Overexpression Phenotype

Abstract Drosophila dishevelled (dsh) functions in two pathways: it is necessary to transduce Wingless (Wg) signaling and it is required in planar cell polarity. To learn more about how Dsh can discriminate between these functions, we performed genetic screens to isolate additional dsh alleles and we examined the potential role of protein phosphorylation by site-directed mutagenesis. We identified two alleles with point mutations in the Dsh DEP domain that specifically disrupt planar polarity signaling. When positioned in the structure of the DEP domain, these mutations are located close to each other and to a previously identified planar polarity mutation. In addition to the requirement for the DEP domain, we found that a cluster of potential phosphorylation sites in a binding domain for the protein kinase PAR-1 is also essential for planar polarity signaling. To identify regions of dsh that are necessary for Wg signaling, we screened for mutations that modified a GMR-GAL4;UAS-dsh overexpression phenotype in the eye. We recovered many alleles of the transgene containing missense mutations, including mutations in the DIX domain and in the DEP domain, the latter group mapping separately from the planar polarity mutations. In addition, several transgenes had mutations within a domain containing a consensus sequence for an SH3-binding protein. We also recovered second-site-suppressing mutations in axin, mapping at a region that may specifically interact with overexpressed Dsh.

The Therapeutic Potential and Role of miRNA, lncRNA, and circRNA in Osteoarthritis

2019 ◽  
Vol 19 (4) ◽  
pp. 255-263 ◽  
Author(s):  
Yuangang Wu ◽  
Xiaoxi Lu ◽  
Bin Shen ◽  
Yi Zeng
Keyword(s):  
Gene Expression ◽  
Gene Therapy ◽  
Extracellular Matrix ◽  
Inflammatory Reaction ◽  
Noncoding Rna ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Protein Translation ◽  
Cochrane Library

Background: Osteoarthritis (OA) is a disease characterized by progressive degeneration, joint hyperplasia, narrowing of joint spaces, and extracellular matrix metabolism. Recent studies have shown that the pathogenesis of OA may be related to non-coding RNA, and its pathological mechanism may be an effective way to reduce OA. Objective: The purpose of this review was to investigate the recent progress of miRNA, long noncoding RNA (lncRNA) and circular RNA (circRNA) in gene therapy of OA, discussing the effects of this RNA on gene expression, inflammatory reaction, apoptosis and extracellular matrix in OA. Methods: The following electronic databases were searched, including PubMed, EMBASE, Web of Science, and the Cochrane Library, for published studies involving the miRNA, lncRNA, and circRNA in OA. The outcomes included the gene expression, inflammatory reaction, apoptosis, and extracellular matrix. Results and Discussion: With the development of technology, miRNA, lncRNA, and circRNA have been found in many diseases. More importantly, recent studies have found that RNA interacts with RNA-binding proteins to regulate gene transcription and protein translation, and is involved in various pathological processes of OA, thus becoming a potential therapy for OA. Conclusion: In this paper, we briefly introduced the role of miRNA, lncRNA, and circRNA in the occurrence and development of OA and as a new target for gene therapy.

Role of key point Mutations in Receptor Binding Domain of SARS-CoV-2 Spike Glycoprotein

2020 ◽  
Vol 20 ◽  
Author(s):  
Bipin Singh
Keyword(s):  
Receptor Binding ◽  
Point Mutations ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
Spike Glycoprotein ◽  
Angiotensin Converting Enzyme 2 ◽  
Recent Outbreak ◽  
Novel Coronavirus ◽  
Genomic Similarity

: The recent outbreak of novel coronavirus (SARS-CoV-2 or 2019-nCoV) and its worldwide spread is posing one of the major threats to human health and the world economy. It has been suggested that SARS-CoV-2 is similar to SARSCoV based on the comparison of the genome sequence. Despite the genomic similarity between SARS-CoV-2 and SARSCoV, the spike glycoprotein and receptor binding domain in SARS-CoV-2 shows the considerable difference compared to SARS-CoV, due to the presence of several point mutations. The analysis of receptor binding domain (RBD) from recently published 3D structures of spike glycoprotein of SARS-CoV-2 (Yan, R., et al. (2020); Wrapp, D., et al. (2020); Walls, A. C., et al. (2020)) highlights the contribution of a few key point mutations in RBD of spike glycoprotein and molecular basis of its efficient binding with human angiotensin-converting enzyme 2 (ACE2).

scholarly journals Role of type III homology repeats in cell adhesive function within the cell-binding domain of fibronectin.

1991 ◽  
Vol 266 (5) ◽  
pp. 3045-3051
Author(s):  
F Kimizuka ◽  
Y Ohdate ◽  
Y Kawase ◽  
T Shimojo ◽  
Y Taguchi ◽  
...  
Keyword(s):  
Binding Domain ◽  
Cell Binding ◽  
Type Iii ◽  
Cell Adhesive ◽  
Cell Binding Domain

scholarly journals MUTATIONAL ANALYSIS OF THE REGION SURROUNDING THE 93D HEAT SHOCK LOCUS OF DROSOPHILA MELANOGASTER

Genetics ◽  
1984 ◽  
Vol 106 (2) ◽  
pp. 249-265
Author(s):  
Jym Mohler ◽  
Mary Lou Pardue
Keyword(s):  
Drosophila Melanogaster ◽  
Heat Shock ◽  
Mutational Analysis ◽  
Point Mutations ◽  
Γ Irradiation ◽  
Lethal Mutations ◽  
Complementation Groups ◽  
In Trans ◽  
Shock Locus ◽  
Shock Proteins

ABSTRACT The region containing subdivisions 93C, 93D and 93E on chromosome 3 of Drosophila melanogaster has been screened for visible and lethal mutations. Treatment with three mutagens, γ irradiation, ethyl methanesulfonate and diepoxybutane, has produced mutations that fall into 20 complementation groups, including the previously identified ebony locus. No point mutations affecting the heat shock locus in 93D were detected; however, a pair of deficiencies that overlap in the region of this locus was isolated. Flies heterozygous in trans for this pair of deficiencies are capable of producing all of the major heat shock puffs (except 93D) and the major heat shock proteins. In addition, these flies show recovery of normal protein synthesis following a heat shock.

scholarly journals LncRNA CRNDE attenuates chemoresistance in gastric cancer via SRSF6-regulated alternative splicing of PICALM

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Feifei Zhang ◽  
Hui Wang ◽  
Jiang Yu ◽  
Xueqing Yao ◽  
Shibin Yang ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Alternative Splicing ◽  
Noncoding Rna ◽  
De Novo ◽  
Acquired Resistance ◽  
Genetic Alterations ◽  
Clinical Samples ◽  
Autophagy Flux ◽  
Resistance To Chemotherapy

AbstractDe novo and acquired resistance, which are mainly mediated by genetic alterations, are barriers to effective routine chemotherapy. However, the mechanisms underlying gastric cancer (GC) resistance to chemotherapy are still unclear. We showed that the long noncoding RNA CRNDE was related to the chemosensitivity of GC in clinical samples and a PDX model. CRNDE was decreased and inhibited autophagy flux in chemoresistant GC cells. CRNDE directly bound to splicing protein SRSF6 to reduce its protein stability and thus regulate alternative splicing (AS) events. We determined that SRSF6 regulated the PICALM exon 14 skip splice variant and triggered a significant S-to-L isoform switch, which contributed to the expression of the long isoform of PICALM (encoding PICALML). Collectively, our findings reveal the key role of CRNDE in autophagy regulation, highlighting the significance of CRNDE as a potential prognostic marker and therapeutic target against chemoresistance in GC.

scholarly journals Type III Collagen is Required for Adipogenesis and Actin Stress Fibre Formation in 3T3-L1 Preadipocytes

Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 156
Author(s):  
Mohammad Al Hasan ◽  
Patricia E. Martin ◽  
Xinhua Shu ◽  
Steven Patterson ◽  
Chris Bartholomew
Keyword(s):  
Quantitative Polymerase Chain Reaction ◽  
Type Iii Collagen ◽  
Type Iii ◽  
Actin Stress Fibre ◽  
Matrix Gene ◽  
Gene Transcripts ◽  
Polymerase Chain ◽  
Oil Red O Staining ◽  
Oil Red O

GPR56 is required for the adipogenesis of preadipocytes, and the role of one of its ligands, type III collagen (ColIII), was investigated here. ColIII expression was examined by reverse transcription quantitative polymerase chain reaction, immunoblotting and immunostaining, and its function investigated by knockdown and genome editing in 3T3-L1 cells. Adipogenesis was assessed by oil red O staining of neutral cell lipids and production of established marker and regulator proteins. siRNA-mediated knockdown significantly reduced Col3a1 transcripts, ColIII protein and lipid accumulation in 3T3-L1 differentiating cells. Col3a1−/− 3T3-L1 genome-edited cell lines abolished adipogenesis, demonstrated by a dramatic reduction in adipogenic moderators: Pparγ2 (88%) and C/ebpα (96%) as well as markers aP2 (93%) and oil red O staining (80%). Col3a1−/− 3T3-L1 cells displayed reduced cell adhesion, sustained active β-catenin and deregulation of fibronectin (Fn) and collagen (Col4a1, Col6a1) extracellular matrix gene transcripts. Col3a1−/− 3T3-L1 cells also had dramatically reduced actin stress fibres. We conclude that ColIII is required for 3T3-L1 preadipocyte adipogenesis as well as the formation of actin stress fibres. The phenotype of Col3a1−/− 3T3-L1 cells is very similar to that of Gpr56−/− 3T3-L1 cells, suggesting a functional relationship between ColIII and Gpr56 in preadipocytes.

scholarly journals Involvement of the long noncoding RNA H19 in osteogenic differentiation and bone regeneration

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Zimo Zhou ◽  
Mohammad Showkat Hossain ◽  
Da Liu
Keyword(s):  
Bone Regeneration ◽  
Osteogenic Differentiation ◽  
Long Noncoding Rna ◽  
Noncoding Rna ◽  
Osteoblast Differentiation ◽  
Osteoclast Differentiation ◽  
Complex Processes ◽  
Osteogenic Induction ◽  
Novel Target

AbstractOsteogenic differentiation and bone regeneration are complex processes involving multiple genes and multiple steps. In this review, we summarize the effects of the long noncoding RNA (lncRNA) H19 on osteogenic differentiation.Osteogenic differentiation includes matrix secretion and calcium mineralization as hallmarks of osteoblast differentiation and the absorption of calcium and phosphorus as hallmarks of osteoclast differentiation. Mesenchymal stem cells (MSCs) form osteoprogenitor cells, pre-osteoblasts, mature osteoblasts, and osteocytes through induction and differentiation. lncRNAs regulate the expression of coding genes and play essential roles in osteogenic differentiation and bone regeneration. The lncRNA H19 is known to have vital roles in osteogenic induction.This review highlights the role of H19 as a novel target for osteogenic differentiation and the promotion of bone regeneration.

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