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Imaging of BrdU‐labeled human metaphase chromosomes with a high resolution scanning ion microprobe
Author(s) -
LeviSetti Riccardo,
Chabala Jan M.,
Gavrilov Konstantin,
Espinosa Rafael,
Le Beau Michelle M.
Publication year - 1997
Publication title -
microscopy research and technique
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 118
eISSN - 1097-0029
pISSN - 1059-910X
DOI - 10.1002/(sici)1097-0029(19970215)36:4<301::aid-jemt8>3.0.co;2-o
Subject(s) - microprobe , metaphase , resolution (logic) , high resolution , biology , chemistry , analytical chemistry (journal) , microbiology and biotechnology , materials science , genetics , chromosome , chromatography , mineralogy , computer science , remote sensing , gene , geology , artificial intelligence
Detailed maps of the A–T distribution within human mitotic chromosomes labeled with BrdU are obtained with a high resolution scanning ion microprobe through the detection of bromine by imaging secondary ion mass spectrometry (SIMS). Corresponding maps of the emission loci of the molecular ion CN describe the overall DNA, RNA and protein distribution in the chromosomes. Several chromosome preparations exhibit base‐specific banding patterns (SIMS‐bands) which mimic the well known G‐ or Q‐bands resulting from conventional staining methods for optical microscopy. SIMS‐bands are more noticeable in mitotic cells at the first cell cycle and after in situ denaturation or Giemsa staining. Sister chromatid exchanges (SCE) at the second cell cycle and beyond, occurring both spontaneously and promoted following cell culture exposure to the chemical aphidicolin (an inhibitor of DNA replication), can be visualized readily from the relative label signal intensities between sister chromatids. The comparison of base‐specific label maps with CN maps, in conjunction with the appearance of base‐specific banding patterns, is informative about protein survival and/or removal following different chromosome preparation protocols. In addition, the resulting condensation state of the chromosomes can be appraised during SIMS analysis from the sample topography (imaged via the collection of mass‐unresolved secondary ions). We demonstrate that imaging SIMS is a powerful complement to existing methods for the study of banding mechanisms and for the elucidation of chromosome structure. The advantages of this novel approach to the systematic and quantitative study of cytogenetic phenomena and methodologies are still largely untapped. Microsc. Res. Tech. 36:301–312, 1997. © 1997 Wiley‐Liss, Inc.