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1.
DNA Repair (Amst) ; 68: 58-67, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29957539

RESUMO

The ATP-dependent chromatin remodeler CSB is implicated in a variety of different DNA repair mechanisms, including transcription-coupled nucleotide excision repair (TC-NER), base excision repair and DNA double strand break (DSB) repair. However, how CSB is regulated in these various repair processes is not well understood. Here we report that the first 30 amino acids of CSB along with two phosphorylation events on S10 and S158, previously reported to be required for CSB function in homologous recombination (HR)-mediated repair, are dispensable for repairing UV-induced DNA damage, suggesting that the regulation of CSB in these two types of repair are carried out by distinct mechanisms. In addition, we show that although the central ATPase domain of CSB is engaged in interactions with both the N- and C-terminal regions, these interactions are disrupted following UV-induced DNA damage. The UV-induced disengagement of the C-terminal region of CSB from the ATPase domain requires two conserved amino acids W1486 and L1488, which are thought to contribute to the hydrophobic core formation of the winged helix domain (WHD) at its C-terminus. Failure to undergo UV-induced dissociation of the C-terminal region of CSB from the ATPase domain is associated with impairment in its UV-induced chromatin association, its UV-induced post-translational modification as well as cell survival. Collectively, these findings suggest that UV-induced dissociation of CSB domain interactions is a necessary step in repairing UV-induced DNA damage and that the WHD of CSB plays a key role in this dissociation.


Assuntos
Dano ao DNA , DNA Helicases/metabolismo , Enzimas Reparadoras do DNA/metabolismo , Reparo do DNA , Proteínas de Ligação a Poli-ADP-Ribose/metabolismo , Domínios Proteicos , Raios Ultravioleta , Adenosina Trifosfatases , Linhagem Celular , Síndrome de Cockayne , DNA/metabolismo , DNA/efeitos da radiação , DNA Helicases/efeitos da radiação , Enzimas Reparadoras do DNA/efeitos da radiação , Humanos , Fosforilação , Proteínas de Ligação a Poli-ADP-Ribose/efeitos da radiação , Processamento de Proteína Pós-Traducional
2.
Mol Cancer Res ; 8(6): 885-95, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20530579

RESUMO

Although C1D has been shown to be involved in DNA double-strand break repair, how C1D expression was induced and the mechanism(s) by which C1D facilitates DNA repair in mammalian cells remain poorly understood. We and others have previously shown that expression of xeroderma pigmentosum B (XPB) protein efficiently compensated the UV irradiation-sensitive phenotype of 27-1 cells, which lack functional XPB. To further explore XPB-regulated genes that could be involved in UV-induced DNA repair, differential display analysis of mRNA levels from CHO-9, 27-1, and 27-1 complemented with wild-type XPB was done and C1D gene was identified as one of the major genes whose expression was significantly upregulated by restoring XPB function. We found that XPB is essential to induce C1D transcription after UV irradiation. The increase in C1D expression effectively compensates for the UV-induced proteolysis of C1D and thus maintains cellular C1D level to cope with DNA damage inflicted by UV irradiation. We further showed that although insufficient to rescue 27-1 cells from UV-induced apoptosis by itself, C1D facilitates XPB DNA repair through direct interaction with XPB. Our findings provided direct evidence that C1D is associated with DNA repair complex and may promote repair of UV-induced DNA damage.


Assuntos
Proteínas Reguladoras de Apoptose/fisiologia , Apoptose/genética , Proteínas Correpressoras/biossíntese , Dano ao DNA/genética , DNA Helicases/fisiologia , Reparo do DNA/genética , Proteínas de Ligação a DNA/fisiologia , Raios Ultravioleta , Animais , Apoptose/efeitos da radiação , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/efeitos da radiação , Células CHO , Proteínas Correpressoras/genética , Proteínas Correpressoras/efeitos da radiação , Cricetinae , Cricetulus , Dano ao DNA/efeitos da radiação , DNA Helicases/genética , DNA Helicases/efeitos da radiação , Reparo do DNA/efeitos da radiação , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/efeitos da radiação , Humanos , Ativação Transcricional/genética , Ativação Transcricional/efeitos da radiação , Regulação para Cima/genética , Regulação para Cima/efeitos da radiação
3.
J Biochem ; 146(3): 327-35, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19451148

RESUMO

Human RECQL4 protein was expressed in insect cells using a baculovirus protein expression system and it was purified to near homogeneity. The protein sedimented at a position between catalase (230 kDa) and ferritin (440 kDa) in glycerol gradient centrifugation, suggesting that it forms homo-multimers. Activity to displace annealed 17-mer oligonucleotide in the presence of ATP was co-sedimented with hRECQL4 protein. In ion-exchange chromatography, both DNA helicase activity and single-stranded DNA-dependent ATPase activity were co-eluted with hRECQL4 protein. The requirements of ATP and Mg for the helicase activity were different from those for the ATPase activity. The data suggest that the helicase migrates on single-stranded DNA in a 3'-5' direction. These results suggest that the hRECQL4 protein exhibits DNA helicase activity.


Assuntos
DNA Helicases/metabolismo , RecQ Helicases/metabolismo , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/isolamento & purificação , Adenosina Trifosfatases/metabolismo , Adenosina Trifosfatases/efeitos da radiação , Trifosfato de Adenosina/metabolismo , Trifosfato de Adenosina/efeitos da radiação , Baculoviridae/genética , Centrifugação com Gradiente de Concentração , Cromatografia por Troca Iônica , Clonagem Molecular , DNA Helicases/genética , DNA Helicases/isolamento & purificação , DNA Helicases/efeitos da radiação , DNA Polimerase I/metabolismo , DNA Polimerase I/efeitos da radiação , DNA Complementar , Células HeLa , Humanos , Concentração de Íons de Hidrogênio , Magnésio/metabolismo , Polidesoxirribonucleotídeos/metabolismo , Ligação Proteica , RecQ Helicases/genética , RecQ Helicases/isolamento & purificação , RecQ Helicases/efeitos da radiação , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/efeitos da radiação , Raios Ultravioleta
4.
J Bacteriol ; 191(5): 1429-38, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19074381

RESUMO

Genomic integrity is critical for an organism's survival and ability to reproduce. In Escherichia coli, the UvrD helicase has roles in nucleotide excision repair and methyl-directed mismatch repair and can limit reactions by RecA under certain circumstances. UvrD303 (D403A D404A) is a hyperhelicase mutant, and when expressed from a multicopy plasmid, it results in UV sensitivity (UV(s)), recombination deficiency, and antimutability. In order to understand the molecular mechanism underlying the UV(s) phenotype of uvrD303 cells, this mutation was transferred to the E. coli chromosome and studied in single copy. It is shown here that uvrD303 mutants are UV sensitive, recombination deficient, and antimutable and additionally have a moderate defect in inducing the SOS response after UV treatment. The UV-sensitive phenotype is epistatic with recA and additive with uvrA and is partially suppressed by removing the LexA repressor. Furthermore, uvrD303 is able to inhibit constitutive SOS expression caused by the recA730 mutation. The ability of UvrD303 to antagonize SOS expression was dependent on its 40 C-terminal amino acids. It is proposed that UvrD303, via its C terminus, can decrease the levels of RecA activity in the cell.


Assuntos
DNA Helicases/química , DNA Helicases/farmacologia , Escherichia coli K12/enzimologia , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/farmacologia , Regulação Bacteriana da Expressão Gênica , Mutação , Recombinases Rec A/metabolismo , Resposta SOS em Genética/efeitos dos fármacos , DNA Helicases/genética , DNA Helicases/efeitos da radiação , DNA Bacteriano/genética , Escherichia coli K12/genética , Escherichia coli K12/metabolismo , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Proteínas de Escherichia coli/efeitos da radiação , Recombinases Rec A/genética , Recombinação Genética , Raios Ultravioleta
5.
Development ; 131(11): 2565-75, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15115755

RESUMO

A Werner syndrome protein homolog in C. elegans (WRN-1) was immunolocalized to the nuclei of germ cells, embryonic cells, and many other cells of larval and adult worms. When wrn-1 expression was inhibited by RNA interference (RNAi), a slight reduction in C. elegans life span was observed, with accompanying signs of premature aging, such as earlier accumulation of lipofuscin and tissue deterioration in the head. In addition, various developmental defects, including small, dumpy, ruptured, transparent body, growth arrest and bag of worms, were induced by RNAi. The frequency of these defects was accentuated by gamma-irradiation, implying that they were derived from spontaneous or induced DNA damage. wrn-1(RNAi) worms showed accelerated larval growth irrespective of gamma-irradiation, and pre-meiotic germ cells had an abnormal checkpoint response to DNA replication blockage. These observations suggest that WRN-1 acts as a checkpoint protein for DNA damage and replication blockage. This idea is also supported by an accelerated S phase in wrn-1(RNAi) embryonic cells. wrn-1(RNAi) phenotypes similar to those of Werner syndrome, such as premature aging and short stature, suggest wrn-1-deficient C. elegans as a useful model organism for Werner syndrome.


Assuntos
Envelhecimento/fisiologia , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/fisiologia , Dano ao DNA/fisiologia , DNA Helicases/metabolismo , Animais , Caenorhabditis elegans/embriologia , Caenorhabditis elegans/efeitos da radiação , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/efeitos da radiação , Clonagem Molecular , DNA Helicases/genética , DNA Helicases/efeitos da radiação , Replicação do DNA , Embrião não Mamífero/citologia , Embrião não Mamífero/fisiologia , Exodesoxirribonucleases , Regulação da Expressão Gênica no Desenvolvimento , Células Germinativas/fisiologia , Humanos , Larva/crescimento & desenvolvimento , Larva/efeitos da radiação , Fenótipo , Interferência de RNA , Radiação Ionizante , RecQ Helicases , Fase S , Homologia de Sequência de Aminoácidos , Síndrome de Werner/etiologia , Helicase da Síndrome de Werner
6.
J Biol Chem ; 279(20): 21169-76, 2004 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-15026416

RESUMO

The Werner syndrome and the Nijmegen breakage syndrome are recessive genetic disorders that show increased genomic instability, cancer predisposition, hypersensitivity to mitomycin C and gamma-irradiation, shortened telomeres, and cell cycle defects. The protein mutated in the premature aging disease known as the Werner syndrome is designated WRN and is a member of the RecQ helicase family. The Nbs1 protein is mutated in Nijmegen breakage syndrome individuals and is part of the mammalian Mre11 complex together with the Mre11 and Rad50 proteins. Here, we show that WRN associates with the Mre11 complex via binding to Nbs1 in vitro and in vivo. In response to gamma-irradiation or mitomycin C, WRN leaves the nucleoli and co-localizes with the Mre11 complex in the nucleoplasm. We detect an increased association between WRN and the Mre11 complex after cellular exposure to gamma-irradiation. Small interfering RNA and complementation experiments demonstrated convergence of WRN and Nbs1 in response to gamma-irradiation or mitomycin C. Nbs1 is required for the Mre11 complex promotion of WRN helicase activity. Taken together, these results demonstrate a functional link between the two genetic diseases with partially overlapping phenotypes in a pathway that responds to DNA double strand breaks and interstrand cross-links.


Assuntos
Proteínas de Ciclo Celular/metabolismo , DNA Helicases/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas Nucleares/metabolismo , Sítios de Ligação , Proteínas de Ciclo Celular/efeitos dos fármacos , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/efeitos da radiação , Linhagem Celular , DNA Helicases/efeitos dos fármacos , DNA Helicases/genética , DNA Helicases/efeitos da radiação , Proteínas de Ligação a DNA/genética , Exodesoxirribonucleases , Raios gama , Células HeLa , Humanos , Proteína Homóloga a MRE11 , Mitomicina/farmacologia , Proteínas Nucleares/efeitos dos fármacos , Proteínas Nucleares/genética , Proteínas Nucleares/efeitos da radiação , RNA Mensageiro/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/efeitos da radiação , RecQ Helicases , Proteínas Recombinantes/metabolismo , Valores de Referência , Transfecção , Helicase da Síndrome de Werner
7.
J Biol Chem ; 277(8): 6280-6, 2002 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-11741924

RESUMO

Bloom's syndrome is a rare human autosomal recessive disorder that combines a marked genetic instability and an increased risk of developing all types of cancers and which results from mutations in both copies of the BLM gene encoding a RecQ 3'-5' DNA helicase. We recently showed that BLM is phosphorylated and excluded from the nuclear matrix during mitosis. We now show that the phosphorylated mitotic BLM protein is associated with a 3'-5' DNA helicase activity and interacts with topoisomerase III alpha. We demonstrate that in mitosis-arrested cells, ionizing radiation and roscovitine treatment both result in the reversion of BLM phosphorylation, suggesting that BLM could be dephosphorylated through the inhibition of cdc2 kinase. This was supported further by our data showing that cdc2 kinase activity is inhibited in gamma-irradiated mitotic cells. Finally we show that after ionizing radiation, BLM is not involved in the establishment of the mitotic DNA damage checkpoint but is subjected to a subcellular compartment change. These findings lead us to propose that BLM may be phosphorylated during mitosis, probably through the cdc2 pathway, to form a pool of rapidly available active protein. Inhibition of cdc2 kinase after ionizing radiation would lead to BLM dephosphorylation and possibly to BLM recruitment to some specific sites for repair.


Assuntos
Adenosina Trifosfatases/genética , Síndrome de Bloom/genética , DNA Helicases/genética , Frações Subcelulares/enzimologia , Adenosina Trifosfatases/metabolismo , Adenosina Trifosfatases/efeitos da radiação , Linfócitos B , Síndrome de Bloom/enzimologia , Proteína Quinase CDC2/antagonistas & inibidores , Proteína Quinase CDC2/efeitos da radiação , Ciclo Celular , Linhagem Celular , DNA Helicases/metabolismo , DNA Helicases/efeitos da radiação , DNA Topoisomerases Tipo I/metabolismo , Raios gama , Humanos , Mitose , RecQ Helicases
8.
J Biol Chem ; 272(30): 18614-20, 1997 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-9228029

RESUMO

A site-directed mutation in motif IV of Escherichia coli DNA helicase II (UvrD) was generated to examine the functional significance of this region. The highly conserved arginine at position 284 was replaced with alanine to construct UvrD-R284A. The ability of the mutant allele to function in methyl-directed mismatch repair and UvrABC-mediated nucleotide excision repair was examined by genetic complementation assays. The R284A substitution abolished function in both DNA repair pathways. To identify the biochemical defects responsible for the loss of biological function, UvrD-R284A was purified to apparent homogeneity, and its biochemical properties were compared with wild-type UvrD. UvrD-R284A failed to unwind a 92-base pair duplex region and was severely compromised in unwinding a 20-base pair duplex region. The Km of UvrD-R284A for ATP was significantly greater than 3 mM compared with 80 microM for UvrD. A large decrease in ATP binding was confirmed using a nitrocellulose filter binding assay. These data suggested that the R284A mutation severely reduced the affinity of helicase II for ATP. The reduced unwinding activity and loss of biological function of UvrD-R284A was probably the result of decreased affinity for ATP. These results implicate motif IV of superfamily I helicases in nucleotide binding and represent the first characterization of a helicase mutation outside motifs I and II that severely impacted the Km for ATP.


Assuntos
Adenosina Trifosfatases/metabolismo , Trifosfato de Adenosina/metabolismo , Arginina/metabolismo , DNA Helicases/metabolismo , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/efeitos da radiação , Sequência de Aminoácidos , Arginina/genética , Sítios de Ligação/genética , Quimotripsina/metabolismo , Sequência Conservada , DNA/metabolismo , DNA Helicases/genética , DNA Helicases/efeitos da radiação , Dimerização , Escherichia coli , Proteínas de Escherichia coli , Cinética , Mutagênese Sítio-Dirigida , Raios Ultravioleta
9.
EMBO J ; 15(8): 1877-84, 1996 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-8617234

RESUMO

MAT1, cyclin H and cdk7 are part of TFIIH, a class II transcription factor which possesses numerous subunits of which several have been shown to be involved in processes other than transcription. Two of them, XPD (ERCC2) and XPB (ERCC3), are helicases involved in nucleotide excision repair (NER), whereas cdk7, cyclin H and MAT1 are thought to participate in cell cycle regulation. MAT1, cyclin H and cdk7 exist as a ternary complex either free or associated with TFIIH from which the latter can be dissociated at high salt concentration. MAT1 is strongly associated with cdk7 and cyclin H. Although not strictly required for the formation and activity of the complex, it stimulates its kinase activity. The kinase activity of TFIIH, which is constant during the cell cycle, is reduced after UV light irradiation.


Assuntos
Quinases Ciclina-Dependentes , Ciclinas/química , Proteínas de Neoplasias/química , Proteínas Serina-Treonina Quinases/química , Fatores de Transcrição TFII , Fatores de Transcrição/química , Sequência de Aminoácidos , Animais , Ciclo Celular , Linhagem Celular , Ciclina H , Ciclinas/genética , Ciclinas/efeitos da radiação , Dano ao DNA , DNA Helicases/química , DNA Helicases/genética , DNA Helicases/efeitos da radiação , Reparo do DNA , Substâncias Macromoleculares , Dados de Sequência Molecular , Estrutura Molecular , Complexos Multienzimáticos/química , Complexos Multienzimáticos/genética , Complexos Multienzimáticos/efeitos da radiação , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/efeitos da radiação , Proteínas Quinases/química , Proteínas Quinases/genética , Proteínas Quinases/efeitos da radiação , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/efeitos da radiação , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/efeitos da radiação , Fator de Transcrição TFIIH , Fatores de Transcrição/genética , Fatores de Transcrição/efeitos da radiação , Raios Ultravioleta , Quinase Ativadora de Quinase Dependente de Ciclina
10.
Radiother Oncol ; 39(1): 43-52, 1996 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8735493

RESUMO

Replication protein A (RPA, also called human single stranded DNA binding protein, hSSB) is a trimeric, multifunctional protein complex involved in DNA replication, DNA repair and recombination. Phosphorylation of RPA p34 subunit is observed after exposure of cells to radiation and other DNA damaging agents, which implicates the protein not only in repair but also in the regulation of replication on damaged DNA template. Here, we show that the phosphorylation observed in RPA p34 after exposure to ionizing radiation, X- or gamma-rays, is reduced and occurs later in primary fibroblasts from patients suffering from ataxia telangiectasia (AT), as compared to normal fibroblasts. We also show that in primary normal human fibroblasts, radiation-induced phosphorylation of RPA p34 is 'age'-dependent and decreases significantly as cultures senesce. Radiation-induced phosphorylation of RPA p34 is nearly absent in non-cycling cells, while the expression of p21cipl/wafl/sdil remains inducible. The results demonstrate a growth-state and culture-age dependency in radiation-induced RPA p34 phosphorylation, and suggest the operation of a signal transduction pathway that is inactivated in senescing or quiescent fibroblasts and defective in AT cells.


Assuntos
Envelhecimento/metabolismo , Ataxia Telangiectasia/patologia , DNA Helicases/efeitos da radiação , Replicação do DNA/efeitos da radiação , DNA de Cadeia Simples/efeitos da radiação , Proteínas de Ligação a DNA/efeitos da radiação , Fibroblastos/efeitos da radiação , Raios gama , Raios X , Ataxia Telangiectasia/metabolismo , Ciclo Celular , Células Cultivadas , Inibidor de Quinase Dependente de Ciclina p21 , Ciclinas/genética , Ciclinas/efeitos da radiação , Dano ao DNA , Reparo do DNA/efeitos da radiação , Inibidores Enzimáticos/efeitos da radiação , Fibroblastos/metabolismo , Regulação da Expressão Gênica/efeitos da radiação , Humanos , Fosforilação/efeitos da radiação , Recombinação Genética/efeitos da radiação , Proteína de Replicação A , Transdução de Sinais/efeitos da radiação
11.
Biochimie ; 73(4): 501-3, 1991 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-1655052

RESUMO

By making use of the gam(+)-plasmid, the so-called gam-dependent radioresistance was studied. This resistance is the result of the interaction between Gam protein (encoded by the gam gene of lambda) and RecBCD enzyme of Escherichia coli. gam-dependent radioresistance is observed in recB+ recC+ recD+ but not in recB+ recC+ recD- cells. It is suggested that Gam protein interacts specifically with the RecD subunit of RecBCD enzyme; the RecBC complex probably retains its activity in the presence of this viral protein.


Assuntos
Bacteriófago lambda/genética , DNA Helicases/genética , Proteínas de Escherichia coli , Escherichia coli/efeitos da radiação , Exodesoxirribonucleases/genética , Proteínas Virais/genética , Bacteriófago lambda/efeitos da radiação , DNA Helicases/efeitos da radiação , Proteínas de Ligação a DNA , Escherichia coli/enzimologia , Escherichia coli/genética , Exodesoxirribonuclease V , Exodesoxirribonucleases/efeitos da radiação , Raios gama , Plasmídeos , Proteínas Virais/efeitos da radiação
12.
J Biol Chem ; 264(2): 1336-43, 1989 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-2536020

RESUMO

The requirement for nucleotide hydrolysis in the DNA repair mechanism of the Escherichia coli UvrABC protein complex has been analyzed. The DNA-activated UvrAB ATPase activity is part of a helicase activity exhibited by the UvrAB protein complex. The helicase acts only on short duplexes and, therefore, is unlike other helicases such as those involved in DNA replication that unwind long duplexes. The strand displacement activity occurs in the 5'----3' direction and requires either ATP or dATP. The helicase activity is inhibited by UV photoproducts. The absence of this activity in a complex formed with proteolyzed UvrB (UvrB*), a complex also deficient in the endonuclease activity, suggests that this activity is important in the repair mechanism. The UvrAB protein complex may remain bound to a damaged site and by coupling the energy derived from ATP hydrolysis, alter the DNA conformation around the damage site to one that is permissive for endonucleolytic events. The conformational changes may take the form of DNA unwinding.


Assuntos
DNA Helicases/metabolismo , Endodesoxirribonucleases/metabolismo , Proteínas de Escherichia coli , Escherichia coli/enzimologia , DNA Helicases/efeitos da radiação , Reparo do DNA , Cinética , Especificidade por Substrato , Termodinâmica , Raios Ultravioleta
13.
Eur J Nucl Med ; 11(5): 166-70, 1985.
Artigo em Inglês | MEDLINE | ID: mdl-2998797

RESUMO

The radiotoxic effects of L-[methyl-11C] methionine were estimated by measuring the accumulation of DNA strand breaks. CHO, Chinese-hamster cells, were incubated in 11C-methionine-containing medium for 60 min at 37 degrees C. The number of unrepaired DNA strand breaks was then examined by the DNA-unwinding method. For comparison, cells were also externally irradiated under similar conditions with gamma radiation (137Cs) or positrons (11C). The relative biological effectiveness of 11C-methionine was estimated to be about 1.


Assuntos
Radioisótopos de Carbono , DNA Helicases/efeitos da radiação , Metionina/toxicidade , Ovário/efeitos dos fármacos , Animais , Autorradiografia , Células Cultivadas , Cricetinae , Cricetulus , Feminino , Ovário/efeitos da radiação , Timidina/metabolismo
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