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6th ESACP Congress, Heidelberg, April 7-11, 1999 |
A054
Many human cancers are associated with structural chromosomal aberrations.
The Philadelphia chromosome [t(9;22); translocation] is the cytogenetic
hallmark of one of the most common human leukemia, Chronic Myelogenous
Leukemia (CML). Despite this fact, there is much less information about the
mechanism leading to the formation of these chromosomal aberrations.
The microscopic analysis of the 3D-nanostructure of these chromatin regions
in intact cell nuclei can contribute to an better understanding of the
spatial organisation of these regions and thus of the formation of chromosome
aberrations induced by ionising radiation. To study the 3D-nanostructure of
these cancer correlated regions, it is highly desirable to use far field
fluorescent light microscopic techniques, e.g. confocal laser scanning
microscopy (CLSM). However, experimental evidence indicates that under
biologically relevant conditions by using objects with the same fluorochrome,
the spatial resolution of the CLSM is limited to about 750 nm in axial
direction and about 300 nm in lateral direction. To overcome this shortcoming
of resolution, a recently developed light microscopical approach, Spectral
Precision Distance microscopy (SPDM) will be presented. This technique is
based on spectrally differential registration of images and quantitative
spectral image analysis of spatially neighbouring nuclear sites. In
combination with specific labelling of very small chromatin targets with dyes
of different spectral signatures by fluorescence in situ hybridisation,
SPDM allows to analyse nuclear topology in three dimensionally conserved
nuclei with a resolution " equivalent " of about 50 nm. A confocal laser
scanning mode of this technique was applied to study the 3D-topology of the
BCR-ABL region involved in the formation of the Philadelphia chromosome
[t(9;22)] of CML patients.
SPECTRAL PRECISION DISTANCE MICROSCOPY IN THE GENOME RESEARCH: INVESTIGATION
OF THE NANOSTRUCTURE OF CANCER CORRELATED REGIONS
Esa A 1, Edelmann P 1, Trakhtenbrot L 2, Cremer C 1
1) Applied Optics and Information Processing, Institute of Applied Physics,
University of Heidelberg, Germany, 2) Institute of Hematology,
The Chaim Sheba Medical Center; Tel Hashomer, Israel.