Digital image analysis of chromatin fibre phenotype after "in situ" digestion with restriction endonucleases

Authors

  • Jaime Gosálvez,

    Corresponding author
    1. Unidad de Genética (A-201), Dpto. de Biología, Edificio de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
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  • Carmen López-Fernández,

    1. Unidad de Genética (A-201), Dpto. de Biología, Edificio de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
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  • José L. Fernández,

    1. Centro Oncológico de Galicia, Laboratorio de Genética, 15006 La Coruña, Spain.
    2. Sección de Genética, Hospital "Teresa Herrera", 15006 La Coruña, Spain.
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  • Vicente J. Goyanes,

    1. Sección de Genética, Hospital "Teresa Herrera", 15006 La Coruña, Spain.
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  • Ismael Buño

    1. Unidad de Genética (A-201), Dpto. de Biología, Edificio de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
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Correspondence author.

Abstract

Restriction Endonucleases (REs) may recognize, cleave and remove DNA from fixed chromatin producing specific chromosome banding patterns. However, the modifications produced in the chromatin fibre are not easy to evaluate and compare. The aim of the present investigation was to visualize differences resulting in the texture of the chromatin fibre from metaphase chromosomes after each digestion using digital image analysis (DIA) facilities. To this purpose, metaphase chromosomes derived from a L-929 mouse cell line were digested with different REs (AluI, HpaII and HaeIII).

Since light microscopy does not permit the observation of the chromatin fibre, DIA was performed on digitalized images of metaphase chromosomes under electron microscopy. The application of a LUT (Look Up Table) within the DIA software assigns a colour to each grey level of a digital image. The results obtained using a particular LUT, which permits the discrimination of specific chromatin fibre phenotypes resulting from each digestion, are reported and compared with those obtained under the light microscope.

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