Structural analysis of heavy ion radiation-induced chromosome aberrations by atomic force microscopy.
Heavy ion radiation (high linear energy transfer, LET, radiation) induces various types of chromosome aberration. In this report, we describe a new method employing an atomic force microscope (AFM) for nanometer-level structural analysis of chromosome damage induced by heavy ion irradiation. Metaphase mouse chromosomes with chromatid gap or chromatid breaks induced by heavy ion irradiation were marked under a light microscope. Then the detailed structure of chromosomes of Giemsa-stained or unstained samples was visualized by the AFM. The height data of chromosomes obtained by AFM provided useful information to distinguish chromatid gaps and breaks. A fibrous structure was observed on the unstained chromosome, the average width of which was about 45.8 nm in the image of AFM. These structures were considered to be 30-nm fibers on the chromosome. The structure of the break point regions induced by neon- or carbon-ion irradiation was imaged by AFM. In some cases, the fibrous structure of break points was detected by AFM imaging after carbon ion irradiation. These observations indicated that AFM is a useful tool for analysis of chromosome aberrations induced by heavy ion radiation.
Murakami
M
M
Division of Radiobiology and Biodosimetry, National Institute of Radiological Sciences, 9-1, Anagawa-4-chome, Inage-ku, 263-8555, Chiba, Japan. drhmmura@nirs.go.jp
Minamihisamatsu
M
M
Sato
K
K
Hayata
I
I
D000818:Animals; D002244:Carbon; D002478:Cells, Cultured; D002869:Chromosome Aberrations; D002875:Chromosomes / Q000528:radiation effects* / Q000648:ultrastructure; D020450:Heavy Ions; D051379:Mice; D018625:Microscopy, Atomic Force / Q000379:methods*; D009356:Neon
D009356:Neon; D002244:Carbon