Three-dimensional structure of G-banded human metaphase chromosomes observed by atomic force microscopy.
The structure of G-bands in human metaphase chromosomes was analyzed by comparison between light microscopic and atomic force microscopic (AFM) images of the same chromosomes. G-bands of the chromosomes were made by trypsin treatment followed by staining with a Giemsa solution. The banded chromosomes examined by light microscopy were dried either in air or in a critical point-drier, and observed by non-contact mode AFM. Air-dried chromosomes after G-band staining showed alternating ridges and grooves on their surface, which corresponded to light-microscopically determined G-positive and G-negative bands, respectively. At high magnification, the G-positive ridges were composed of densely packed chromatin fibers, while the fibers were loose in the G-negative grooves. Fibers bridging the gap between sister chromatids of a mitotic pair were often found, especially in the G-positive portions. These findings suggest that the G-banding pattern reflects the high-order structure of human metaphase chromosomes.
Hoshi
O
O
Department of Cellular Function, Niigata University Graduate School of Medical and Dental Sciences, Japan.
Ushiki
T
T
D001399:Azure Stains; D002871:Chromosome Banding; D002877:Chromosomes, Human / Q000235:genetics / Q000648:ultrastructure*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008214:Lymphocytes / Q000648:ultrastructure; D008677:Metaphase; D018625:Microscopy, Atomic Force / Q000379:methods*; D014357:Trypsin
D001399:Azure Stains; D014357:Trypsin