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Wyszukujesz frazę "dnaQ49" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
UV- and MMS-induced mutagenesis of lO(am)8 phage under nonpermissive conditions for phage DNA replication.
Autorzy:
Krwawicz, Joanna
Czajkowska, Anna
Felczak, Magdalena
Pietrzykowska, Irena
Powiązania:
https://bibliotekanauki.pl/articles/1043364.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
mutagenesis
dnaQ49
λ phage
mutL
DNA replication
UmuDC
uvrA
Opis:
Mutagenesis in Escherichia coli, a subject of many years of study is considered to be related to DNA replication. DNA lesions nonrepaired by the error-free nucleotide excision repair (NER), base excision repair (BER) and recombination repair (RR), stop replication at the fork. Reinitiation needs translesion synthesis (TLS) by DNA polymerase V (UmuC), which in the presence of accessory proteins, UmuD', RecA and ssDNA-binding protein (SSB), has an ability to bypass the lesion with high mutagenicity. This enables reinitiation and extension of DNA replication by DNA polymerase III (Pol III). We studied UV- and MMS-induced mutagenesis of λO(am)8 phage in E. coli 594 sup+ host, unable to replicate the phage DNA, as a possible model for mutagenesis induced in nondividing cells (e.g. somatic cells). We show that in E. coli 594 sup+ cells UV- and MMS-induced mutagenesis of λO(am)8 phage may occur. This mutagenic process requires both the UmuD' and C proteins, albeit a high level of UmuD' and low level of UmuC seem to be necessary and sufficient. We compared UV-induced mutagenesis of λO(am)8 in nonpermissive (594 sup+) and permissive (C600 supE) conditions for phage DNA replication. It appeared that while the mutagenesis of λO(am)8 in 594 sup+ requires the UmuD' and C proteins, which can not be replaced by other SOS-inducible protein(s), in C600 supE their functions may be replaced by other inducible protein(s), possibly DNA polymerase IV (DinB). Mutations induced under nonpermissive conditions for phage DNA replication are resistant to mismatch repair (MMR), while among those induced under permissive conditions, only about 40% are resistant.
Źródło:
Acta Biochimica Polonica; 2003, 50, 4; 921-939
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spontaneous mutagenesis in exponentially growing and stationary-phase, umuDC-proficient and -deficient, Escherichia coli dnaQ49.
Autorzy:
Nowosielska, Anetta
Nieminuszczy, Jadwiga
Grzesiuk, Elżbieta
Powiązania:
https://bibliotekanauki.pl/articles/1041546.pdf
Data publikacji:
2004
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
dnaQ49
argE3→Arg+ revertants
E. coli
Pol V
spontaneous mutagenesis
stationary-phase mutations
Opis:
Spontaneous mutations arise not only in exponentially growing bacteria but also in non-dividing or slowly dividing stationary-phase cells. In the latter case mutations are called adaptive or stationary-phase mutations. High spontaneous mutability has been observed in temperature sensitive Escherichia coli dnaQ49 strain deficient in 3'→5' proofreading activity assured by the ε subunit of the main replicative polymerase, Pol III. The aim of this study was to evaluate the effects of the dnaQ49 mutation and deletion of the umuDC operon encoding polymerase V (Pol V) on spontaneous mutagenesis in growing and stationary-phase E. coli cells. Using the argE3OC →Arg+ reversion system in the AB1157 strain, we found that the level of growth-dependent and stationary-phase Arg+ revertants was significantly increased in the dnaQ49 mutant at the non-permissive temperature of 37°C. At this temperature, in contrast to cultures grown at 28°C, SOS functions were dramatically increased. Deletion of the umuDC operon in the dnaQ49 strain led to a 10-fold decrease in the level of Arg+ revertants in cultures grown at 37°C and only to a 2-fold decrease in cultures grown at 28°C. Furthermore, in stationary-phase cultures Pol V influenced spontaneous mutagenesis to a much lesser extent than in growing cultures. Our results indicate that the level of Pol III desintegration, dependent on the temperature of incubation, is more critical for spontaneous mutagenesis in stationary-phase dnaQ49 cells than the presence or absence of Pol V.
Źródło:
Acta Biochimica Polonica; 2004, 51, 3; 683-692
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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