The delayed quinacrine mustard fluorescence from the C-blocks of Apodemus argenteus is due to the introduction of nicks into the DNA.
Zoolog Sci
; 24(6): 588-95, 2007 Jun.
Article
em En
| MEDLINE
| ID: mdl-17867860
ABSTRACT
"Delayed QM-fluorescence" refers to the unusual kinetics of fluorescence from most of the C-heterochromatic regions of the chromosomes of the small Japanese field mouse Apodemus argenteus. When stained with quinacrine mustard (QM-stained), these C-heterochromatic regions emit weak fluorescence immediately after exposure to blue light (BL); they emit bright fluorescence within a few minutes; and the intensity of the fluorescence gradually decreases after maximum fluorescence has been recorded. To elucidate the mechanism of this phenomenon, we used acridine orange staining (AO-staining) and a modified version of the in situ nick-translation method. Focusing on the large C-heterochromatic region (C-block) of the X chromosome, we noted that AO-stained C-blocks emitted greenish fluorescence, while QM-stained and BL-exposed (QM-BL-processed) C-blocks emitted reddish fluorescence upon AO-staining after removal of QM. These findings suggested that the C-block DNA of A. argenteus might undergo a structural change, such as strand breaks, during QM-BL processing. Application of the modified in situ nick-translation method revealed the generation of an appreciable number of nicks in the C-block DNA by QM-BL processing. No such nick formation was observed in the C-blocks of three other mammalian species Apodemus peninsulae, Microtus montebelli, and Urotrichus talpoides. Our findings support the hypothesis that nick formation due to exposure to BL might play a primary role in inducing delayed QM-fluorescence in the C-blocks of A. argenteus. On the basis of the present and earlier findings, we propose a probable mechanism for delayed QM-fluorescence in A. argenteus chromosomes.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Mostarda de Quinacrina
/
Heterocromatina
/
Murinae
/
Quebras de DNA de Cadeia Simples
/
Corantes Fluorescentes
Limite:
Animals
Idioma:
En
Revista:
Zoolog Sci
Assunto da revista:
BIOLOGIA
Ano de publicação:
2007
Tipo de documento:
Article
País de afiliação:
Japão