Determination of low-abundance single-base point mutations based on endonuclease IV and branch migration system

2020 ◽  
Vol 1134 ◽  
pp. 28-33
Author(s):  
Xiaofeng Tang ◽  
Na Chen ◽  
Ruijie Liu ◽  
Qingyi Hu ◽  
Na Liu ◽  
...  
Keyword(s):  
Point Mutations ◽  
Base Point ◽  
Branch Migration ◽  
Single Base ◽  
Migration System

scholarly journals Impact of point-mutations on the hybridization affinity of surface-bound DNA/DNA and RNA/DNA oligonucleotide-duplexes: Comparison of single base mismatches and base bulges

2008 ◽  
Vol 8 (1) ◽  
pp. 48 ◽  
Author(s):  
Thomas Naiser ◽  
Oliver Ehler ◽  
Jona Kayser ◽  
Timo Mai ◽  
Wolfgang Michel ◽  
...  
Keyword(s):  
Point Mutations ◽  
Single Base ◽  
Dna And Rna

scholarly journals Somatic Mutations During an Immune Response inXenopusTadpoles

1995 ◽  
Vol 4 (3) ◽  
pp. 227-234 ◽  
Author(s):  
Melanie Wilson ◽  
Anne Marcuz ◽  
Louis Du Pasquier
Keyword(s):  
Immune Response ◽  
Somatic Mutations ◽  
Somatic Hypermutation ◽  
Point Mutations ◽  
Base Point ◽  
High Ratio ◽  
Cell Repertoire ◽  
Cdna Sequences ◽  
B Cell Repertoire ◽  
Reduced Rate

The tadpole B-cell repertoire is less diverse than that of the adult frog; their antibodies are of lower affinity and are less heterogenous. In order to determine whether this difference is due to a lack of or a reduced rate of somatic hypermutation, we analyzed and compared cDNA sequences utilizing VH1 elements with germline counterparts in isogenic LG7 tadpoles during an immune response. Indeed, tadpole VH1 sequences contained somatic mutations. There were zeo to 5 mutations per sequence, all single base-point mutations, with the high ratio of GC to AT base-pair alterations similar to that observed in adult frogs.

scholarly journals The phasmid as a tool for plasmid genetics: II. Isolation of point mutations that affect replication of a ColE1-related plasmid

1982 ◽  
Vol 40 (3) ◽  
pp. 233-247 ◽  
Author(s):  
Gianni Cesareni ◽  
Luisa Castagnoli ◽  
Sydney Brenner
Keyword(s):  
Copy Number ◽  
Point Mutations ◽  
Plasmid Replication ◽  
Single Base ◽  
Lambdoid Phage ◽  
Copy Number Plasmid ◽  
High Copy Number Plasmid ◽  
Single Base Pair ◽  
Related Plasmid ◽  
Single Base Pair Change

SUMMARYThe insertion of a high-copy-number plasmid into a lambdoid phage chromosome which lacks a functional repressor gene confers on the hybrid ‘phasmid’ the capacity to grow on an immune lysogen. This was found to be due to titration of repressor because of plasmid replication. We have exploited this property in order to isolate mutants that affect plasmid replication. These mutants have been mapped in a region that was previously characterized as necessary for plasmid replication and incompatibility properties. Some of the mutations could revert at frequencies characteristic of single-base-pair change mutations.

GENETIC STUDIES OF PIGMENTATION OF STAPHYLOCOCCUS AUREUS

1967 ◽  
Vol 13 (4) ◽  
pp. 389-395 ◽  
Author(s):  
Robert A. Altenbern
Keyword(s):  
Staphylococcus Aureus ◽  
Optical Density ◽  
Point Mutations ◽  
Low Frequency ◽  
Pigment Content ◽  
Single Site ◽  
Genetic Studies ◽  
Large Numbers ◽  
Acridine Dyes

Exposure of cells of several strains of Staphylococcus aureus to 50 or 100 μg of N-methyl-N′-nitro-N-nitrosoguanidine for 30 to 60 minutes induced large numbers of mutants with pigment content different from that of the parent. By determination of the amount of pigment as related to the optical density of the cells, four to seven classes of pigmentation mutants could be defined. Mutants with pigment content differing from that of the parent could readily be mutated to other pigmentation states and are thus probable point mutations. In contrast, completely white mutants could not be induced by the mutagen to any degree of pigmentation and possibly represent minor deletions or cumulative single-site mutations in the chromosome. Growth of parent strains in media containing acridine dyes occasionally produced a low frequency (0.01%) of white mutants. Mutants differing in pigment content from that of the parent were unable to produce coagulase during growth, although the parent cultures elaborated considerable coagulase under identical conditions.

scholarly journals Accurate Determination of Phenotypic Information from Historic Thoroughbred Horses by Single Base Extension

PLoS ONE ◽  
2010 ◽  
Vol 5 (12) ◽  
pp. e15172 ◽  
Author(s):  
Michael G. Campana ◽  
C. Mark Whitten ◽  
Ceiridwen J. Edwards ◽  
Frauke Stock ◽  
Angela M. Murphy ◽  
...  
Keyword(s):  
Accurate Determination ◽  
Single Base Extension ◽  
Single Base ◽  
Phenotypic Information ◽  
Base Extension ◽  
Thoroughbred Horses

scholarly journals Role of Residues W228 and Y233 in the Structure and Activity of Metallo-β-Lactamase GIM-1

2015 ◽  
Vol 60 (2) ◽  
pp. 990-1002 ◽  
Author(s):  
Susann Skagseth ◽  
Trine Josefine Carlsen ◽  
Gro Elin Kjæreng Bjerga ◽  
James Spencer ◽  
Ørjan Samuelsen ◽  
...  
Keyword(s):  
Active Site ◽  
Active Sites ◽  
Point Mutations ◽  
Resistant Bacteria ◽  
Antibiotic Resistant ◽  
X Ray Crystallography ◽  
Steady State Kinetics ◽  
Hydrophilic Residues

ABSTRACTMetallo-β-lactamases (MBLs) hydrolyze virtually all β-lactam antibiotics, including penicillins, cephalosporins, and carbapenems. The worldwide emergence of antibiotic-resistant bacteria harboring MBLs poses an increasing clinical threat. The MBL German imipenemase-1 (GIM-1) possesses an active site that is narrower and more hydrophobic than the active sites of other MBLs. The GIM-1 active-site groove is shaped by the presence of the aromatic side chains of tryptophan at residue 228 and tyrosine at residue 233, positions where other MBLs harbor hydrophilic residues. To investigate the importance of these two residues, eight site-directed mutants of GIM-1, W228R/A/Y/S and Y233N/A/I/S, were generated and characterized using enzyme kinetics, thermostability assays, and determination of the MICs of representative β-lactams. The structures of selected mutants were obtained by X-ray crystallography, and their interactions with β-lactam substrates were modeledin silico. Steady-state kinetics revealed that both positions are important to GIM-1 activity but that the effects of individual mutations vary depending on the β-lactam substrate. Activity against type 1 substrates bearing electron-donating C-3/C-4 substituents (cefoxitin, meropenem) could be enhanced by mutations at position 228, whereas hydrolysis of type 2 substrates (benzylpenicillin, ampicillin, ceftazidime, imipenem) with methyl or positively charged substituents was favored by mutations at position 233. The crystal structures showed that mutations at position 228 or the Y233A variant alters the conformation of GIM-1 loop L1 rather than that of loop L3, on which the mutations are located. Taken together, these data show that point mutations at both positions 228 and 233 can influence the catalytic properties and the structure of GIM-1.

Determination of cis/trans phase of variations in the MC1R gene with allele-specific PCR and single base extension

2008 ◽  
Vol 29 (23) ◽  
pp. 4780-4787 ◽  
Author(s):  
Jonas Mengel-From ◽  
Claus Børsting ◽  
Juan J. Sanchez ◽  
Hans Eiberg ◽  
Niels Morling
Keyword(s):  
Single Base Extension ◽  
Mc1r Gene ◽  
Single Base ◽  
Specific Pcr ◽  
Base Extension ◽  
Allele Specific ◽  
Allele Specific Pcr

scholarly journals Base editors: modular tools for the introduction of point mutations in living cells

2019 ◽  
Vol 3 (5) ◽  
pp. 483-491 ◽  
Author(s):  
Mallory Evanoff ◽  
Alexis C. Komor
Keyword(s):  
Synthetic Biology ◽  
Genome Editing ◽  
Genome Engineering ◽  
Point Mutations ◽  
Living Cells ◽  
Single Base ◽  
New Family ◽  
Alternative Techniques ◽  
Cas Proteins ◽  
Modular Nature

Base editors are a new family of programmable genome editing tools that fuse ssDNA (single-stranded DNA) modifying enzymes to catalytically inactive CRISPR-associated (Cas) endonucleases to induce highly efficient single base changes. With dozens of base editors now reported, it is apparent that these tools are highly modular; many combinations of ssDNA modifying enzymes and Cas proteins have resulted in a variety of base editors, each with its own unique properties and potential uses. In this perspective, we describe currently available base editors, highlighting their modular nature and describing the various options available for each component. Furthermore, we briefly discuss applications in synthetic biology and genome engineering where base editors have presented unique advantages over alternative techniques.

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