scholarly journals MISMATCH REPAIR AND REPAIR OF INSERTION/DELETION LOOPS IN EUKARYOTIC DNA

2016 ◽  
Vol 1 (3) ◽  
pp. 72-75
Author(s):  
Минакина ◽  
Liliya Minakina ◽  
Непомнящих ◽  
Svetlana Nepomnyashchikh ◽  
Егорова ◽  
...  
Keyword(s):  
Mismatch Repair ◽  
Nuclear Antigen ◽  
Proliferating Cells ◽  
Base Pairs ◽  
Dna Mutation ◽  
Mismatch Correction ◽  
Msh2 Protein ◽  
Efficiency Parameter ◽  
Eukaryotic Dna ◽  
Exonuclease 1

The mismatch repair (MMR) system detects non-Watson – Crick base pairs as well as the defects, appearing in course of DNA replication, and helps to eliminate them by catalyzing the excision of the defect-containing region of daughter DNA and its error-free resynthesis. Thus, MMR remarkably improves the fidelity of replication. After separation, both strands contain non-repairable damages and the mismatches may generate DNA mutation in 50 % of cell progeny after next replication. MMR dysfunction causes surge of mutation rate, abnormal recombination, and cancer in humans and animals. Therefore, the main MMR efficiency parameter is mismatch correction before the next replication cycle. Mismatch detection is made by the MSH2 protein, which forms a heterodimer with either MSH6 or MSH3 (Mut S), depending on the damage (MSH6 is needed for the amendment of single base mispairs, whereas both MSH3 and MSH6 can correct IDLs). A heterodimer of MLH1 and PMS2 (Mut L) controls the interaction between the mismatch-detecting complex of proteins and other proteins essential for MMR, including exonuclease 1, helicase, nuclear antigen of proliferating cells, single-stranded DNA-binding protein and DNA polymerases δ and ε. MLH1 can form a heterodimer with two additional proteins – MLH3 and PMS1. PMS2 is required for the correction of single based mismatches, and PMS2 and MLH3 contribute to the correction of IDLs. The Nobel Prize in Chemistry 2015 was awarded for the studies of DNA repair, i.a. MMR.

Mismatch repair, genetic stability and tumour avoidance

1995 ◽  
Vol 347 (1319) ◽  
pp. 89-95 ◽  
Keyword(s):  
Mismatch Repair ◽  
Dna Sequences ◽  
Dna Ligase ◽  
Cytotoxic Action ◽  
Repair System ◽  
Base Pairs ◽  
Mismatch Correction ◽  
Nuclear Extracts ◽  
Mutation Avoidance

Escherischia coli methyl-directed mismatch repair eliminates premutagenic lesions that arise via DNA biosynthetic errors; components of the repair system also block ectopic recombination between diverged DNA sequences. A mismatch-dependent, methyl-directed excision reaction that accounts for function of the system in replication fidelity has been reconstituted in a purified system dependent on ten activities. The reaction displays a broad specificity for mismatched base pairs and is characterized by an unusual bidirectional excision capability. Human cell nuclear extracts support strand-specific mismatch correction in a reaction that is similar to bacterial repair, with respect to both mismatch specificity and unusual features of mechanism. Like the bacterial system, the human pathway also functions in mutation avoidance because several classes of mutator human cells are deficient in the reaction. These include an alkylation-tolerance cell line that is resistant to the cytotoxic action of N -methyl- N' -nitro-nitrosoguanidine, as well as hypermutable RER+ tumour cells such as those associated with hereditary non-polyposis colon cancer. In vitro experiments indicate that the human repair reaction is dependent on at least six activities, excluding DNA ligase, and that distinct defects in the system can lead to the RER+ phenotype.

scholarly journals Rad27 and Exo1 function in different excision pathways for mismatch repair in Saccharomyces cerevisiae

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Felipe A. Calil ◽  
Bin-Zhong Li ◽  
Kendall A. Torres ◽  
Katarina Nguyen ◽  
Nikki Bowen ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mismatch Repair ◽  
Dna Mismatch Repair ◽  
Dna Mismatch ◽  
Eukaryotic Dna ◽  
Mutl Homolog 1 ◽  
Exonuclease 1 ◽  
Dna Substrate ◽  
Mmr Proteins

AbstractEukaryotic DNA Mismatch Repair (MMR) involves redundant exonuclease 1 (Exo1)-dependent and Exo1-independent pathways, of which the Exo1-independent pathway(s) is not well understood. The exo1Δ440-702 mutation, which deletes the MutS Homolog 2 (Msh2) and MutL Homolog 1 (Mlh1) interacting peptides (SHIP and MIP boxes, respectively), eliminates the Exo1 MMR functions but is not lethal in combination with rad27Δ mutations. Analyzing the effect of different combinations of the exo1Δ440-702 mutation, a rad27Δ mutation and the pms1-A99V mutation, which inactivates an Exo1-independent MMR pathway, demonstrated that each of these mutations inactivates a different MMR pathway. Furthermore, it was possible to reconstitute a Rad27- and Msh2-Msh6-dependent MMR reaction in vitro using a mispaired DNA substrate and other MMR proteins. Our results demonstrate Rad27 defines an Exo1-independent eukaryotic MMR pathway that is redundant with at least two other MMR pathways.

A Mutation in a Saccharomyces cerevisiae Gene (RAD3) Required for Nucleotide Excision Repair and Transcription Increases the Efficiency of Mismatch Correction

Genetics ◽  
1996 ◽  
Vol 144 (2) ◽  
pp. 459-466 ◽  
Author(s):  
Yingying Yang ◽  
Anthony L Johnson ◽  
Leland H Johnston ◽  
Wolfram Siede ◽  
Errol C Friedberg ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mismatch Repair ◽  
Excision Repair ◽  
Spontaneous Mutation ◽  
Surprising Result ◽  
Spontaneous Mutation Rate ◽  
Mismatch Correction ◽  
Nucleotide Excision ◽  
Repair Genes ◽  
Type Strains

Abstract RAD3 functions in DNA repair and transcription in Saccharomyces cerevisiae and particular rad3 alleles confer a mutator phenotype, possibly as a consequence of defective mismatch correction. We assessed the potential involvement of the Rad3 protein in mismatch correction by comparing heteroduplex repair in isogenic rad3-1 and wild-type strains. The rad3-1 allele increased the spontaneous mutation rate but did not prevent heteroduplex repair or bias its directionality. Instead, the efficiency of mismatch correction was enhanced in the rad3-1 strain. This surprising result prompted us to examine expression of yeast mismatch repair genes. We determined that MSH2, but not MLH1, is transcriptionally regulated during the cell-cycle like PMSl, and that rad3-1 does not increase the transcript levels for these genes in log phase cells. These observations suggest that the rad3-1 mutation gives rise to an enhanced efficiency of mismatch correction via a process that does not involve transcriptional regulation of mismatch repair. Interestingly, mismatch repair also was more efficient when error-editing by yeast DNA polymerase δ was eliminated. We discuss our results in relation to possible mechanisms that may link the rad3-1 mutation to mismatch correction efficiency.

scholarly journals Spontaneous and frequent conformational dynamics induced by A…A mismatch in d(CAA)·d(TAG) duplex

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yogeeshwar Ajjugal ◽  
Kripi Tomar ◽  
D. Krishna Rao ◽  
Thenmalarchelvi Rathinavelan
Keyword(s):  
Mismatch Repair ◽  
Conformational Dynamics ◽  
Md Simulations ◽  
Umbrella Sampling ◽  
Base Flipping ◽  
Base Pairs ◽  
2D Noesy ◽  
Junction Formation ◽  
Nmr Techniques ◽  
Transient Events

AbstractBase pair mismatches in DNA can erroneously be incorporated during replication, recombination, etc. Here, the influence of A…A mismatch in the context of 5′CAA·5′TAG sequence is explored using molecular dynamics (MD) simulation, umbrella sampling MD, circular dichroism (CD), microscale thermophoresis (MST) and NMR techniques. MD simulations reveal that the A…A mismatch experiences several transient events such as base flipping, base extrusion, etc. facilitating B–Z junction formation. A…A mismatch may assume such conformational transitions to circumvent the effect of nonisostericity with the flanking canonical base pairs so as to get accommodated in the DNA. CD and 1D proton NMR experiments further reveal that the extent of B–Z junction increases when the number of A…A mismatch in d(CAA)·d(T(A/T)G) increases (1–5). CD titration studies of d(CAA)·d(TAG)n=5 with the hZαADAR1 show the passive binding between the two, wherein, the binding of protein commences with B–Z junction recognition. Umbrella sampling simulation indicates that the mismatch samples anti…+ syn/+ syn…anti, anti…anti & + syn…+ syn glycosyl conformations. The concomitant spontaneous transitions are: a variety of hydrogen bonding patterns, stacking and minor or major groove extrahelical movements (with and without the engagement of hydrogen bonds) involving the mismatch adenines. These transitions frequently happen in anti…anti conformational region compared with the other three regions as revealed from the lifetime of these states. Further, 2D-NOESY experiments indicate that the number of cross-peaks diminishes with the increasing number of A…A mismatches implicating its dynamic nature. The spontaneous extrahelical movement seen in A…A mismatch may be a key pre-trapping event in the mismatch repair due to the accessibility of the base(s) to the sophisticated mismatch repair machinery.

HEAT SHOCK PROTEIN 90 (90) IN AGE-DEPENDENT CHANGES IN THE NUMBER OF FIBROBLASTS IN HUMAN SKIN

2020 ◽  
pp. 40-45
Author(s):  
А. Г. Гунин ◽  
Н. Н. Голубцова ◽  
Н. К. Корнилова
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Heat Shock Protein 90 ◽  
Nuclear Antigen ◽  
Positive Staining ◽  
Proliferating Cells ◽  
Age Related ◽  
Age Dependent ◽  
Human Dermis ◽  
Hsp 90

Целью работы стало исследование содержания белка теплового шока 90 ( HSP 90) в фибробластах дермы человека от эмбрионального развития и до глубокой старости (от 20 нед беременности до 85 лет), а также определение значения HSP 90 для возрастных изменений численности фибробластов в дерме человека. HSP 90, ядерный антиген пролиферирующих клеток ( PCNA ) выявляли в срезах кожи непрямым иммуногистохимическим методом. Результаты показали, что в коже человека от 20 нед беременности до 20 лет доля фибробластов дермы с положительной окраской на HSP 90 остается постоянной. С 21 года до 60 лет наблюдают планомерное уменьшение доли фибробластов дермы, имеющих положительную окраску на HSP 90. У людей 61-85 лет происходит резкое увеличение доли фибробластов дермы с положительной окраской на HSP 90. Возрастные изменения содержания HSP 90 положительных фибробластов в дерме статистически не связаны с возрастным уменьшением общего количества и доли PCNA -положительных фибробластов в дерме. The aim of this work was to examine the content of heat shock protein 90 ( HSP 90) in fibroblasts of human dermis from the development until deep aging (from 20 weeks of pregnancy until 85 years old), and defining of a role of HSP 90 in age-dependent changes in the number of fibroblasts in the dermis. HSP 90, proliferating cells nuclear antigen ( PCNA ) were detected with indirect immunohistochemical technique. Results showed that a portion of fibroblasts with positive staining for HSP 90 in the dermis is not changed from 20 weeks of development to 20 years old. Percent of HSP 90 positive fibroblasts in dermis is decreased from 21 to 60 years old. From 61 year, the number of HSP 90 positive fibroblasts in dermis is increased. Age-related changes in the number of HSP 90 positive fibroblasts is not statistically associated with an age-related decrease in a total number and percent of PCNA positive fibroblasts the dermis.

scholarly journals Distinct Structural Alterations in Proliferating Cell Nuclear Antigen Block DNA Mismatch Repair

Biochemistry ◽  
2013 ◽  
Vol 52 (33) ◽  
pp. 5611-5619 ◽  
Author(s):  
Lynne M. Dieckman ◽  
Elizabeth M. Boehm ◽  
Manju M. Hingorani ◽  
M. Todd Washington
Keyword(s):  
Mismatch Repair ◽  
Proliferating Cell Nuclear Antigen ◽  
Dna Mismatch Repair ◽  
Nuclear Antigen ◽  
Structural Alterations ◽  
Dna Mismatch ◽  
Proliferating Cell

scholarly journals Nuclear localization of human DNA mismatch repair protein exonuclease 1 (hEXO1)

2007 ◽  
Vol 35 (8) ◽  
pp. 2609-2619 ◽  
Author(s):  
Nina Østergaard Knudsen ◽  
Finn Cilius Nielsen ◽  
Lena Vinther ◽  
Ronni Bertelsen ◽  
Steen Holten-Andersen ◽  
...  
Keyword(s):  
Mismatch Repair ◽  
Nuclear Localization ◽  
Dna Mismatch Repair ◽  
Dna Mismatch ◽  
Human Dna ◽  
Repair Protein ◽  
Exonuclease 1 ◽  
Mismatch Repair Protein

Paralogs of Atlantic salmon myoblast determination factor genes are distinctly regulated in proliferating and differentiating myogenic cells

2010 ◽  
Vol 298 (6) ◽  
pp. R1615-R1626 ◽  
Author(s):  
Neil I. Bower ◽  
Ian A. Johnston
Keyword(s):  
Cell Cycle ◽  
Amino Acids ◽  
Amino Acid ◽  
Atlantic Salmon ◽  
Antigen Expression ◽  
Nuclear Antigen ◽  
Quiescent State ◽  
Mrna Levels ◽  
Proliferating Cells

The mRNA expression of myogenic regulatory factors, including myoD1 (myoblast determination factor) gene paralogs, and their regulation by amino acids and insulin-like growth factors were investigated in primary cell cultures isolated from fast myotomal muscle of Atlantic salmon ( Salmo salar). The cell cycle and S phase were determined as 28.1 and 13.3 h, respectively, at 18°C. Expression of myoD1b and myoD1c peaked at 8 days of culture in the initial proliferation phase and then declined more than sixfold as cells differentiated and was correlated with PCNA (proliferating cell nuclear antigen) expression ( R = 0.88, P < 0.0001; R = 0.70, P < 0.0001). In contrast, myoD1a transcripts increased from 2 to 8 days and remained at elevated levels as myotubes were formed. mRNA levels of myoD1c were, on average, 3.1- and 5.7-fold higher than myoD1a and myoD1b, respectively. Depriving cells of amino acids and serum led to a rapid increase in pax7 and a decrease in myoD1c and PCNA expression, indicating a transition to a quiescent state. In contrast, amino acid replacement in starved cells produced significant increases in myoD1c (at 6 h), PCNA (at 12 h), and myoD1b (at 24 h) and decreases in pax7 expression as cells entered the cell cycle. Our results are consistent with temporally distinct patterns of myoD1c and myoD1b expression at the G1 and S/G2 phases of the cell cycle. Treatment of starved cells with insulin-like growth factor I or II did not alter expression of the myoD paralogs. It was concluded that, in vitro, amino acids alone are sufficient to stimulate expression of genes regulating myogenesis in myoblasts involving autocrine/paracrine pathways. The differential responses of myoD paralogs during myotube maturation and amino acid treatments suggest that myoD1b and myoD1c are primarily expressed in proliferating cells and myoD1a in differentiating cells, providing evidence for their subfunctionalization following whole genome and local duplications in the Atlantic salmon lineage.

PCNA and total nuclear protein content as markers of cell proliferation in pea tissue

1992 ◽  
Vol 102 (1) ◽  
pp. 71-78 ◽  
Author(s):  
SANDRA CITTERIO ◽  
SERGIO SGORBATI ◽  
MARISA LEVI ◽  
BRUNO MARIA COLOMBO ◽  
ELIO SPARVOLI
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Protein Content ◽  
Time Course ◽  
Nuclear Protein ◽  
Flow Cytometric Analysis ◽  
Nuclear Antigen ◽  
Cycle Phase ◽  
Proliferating Cells ◽  
Embryo Cells

The identification of cell proliferation markers has been shown to be a useful tool with which to study basic mechanisms of cell cycle progression. The use of immunofluorescence techniques revealed the presence of the proliferating cell nuclear antigen (PCNA) in pea tissue, where we observed a high PCNA expression in proliferating cells of the root meristem compared to noncycling cells of the differentiated leaf. The presence of PCNA was monitored also during the time-course of seed germination, before, during and after the cell cycle resumption of the embryo cells. PCNA is present in embryo cells not only during and after resumption of the cell cycle but also before, when cells have not yet begun replicating their genome. A bivariate flow cytometric analysis of DNA and nuclear protein content was used to localize precisely the cells of the examined pea tissues in different cell cycle phase subcompartments. A high correlation was found between the degree of cell proliferation and the protein content of G1 nuclei, on the one hand, and the percentage of PCNA positive cells on the other.

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