Abstract
A method has been developed for isolating metaphase chromosomes from Microtus agrestis fibroblasts in relatively large quantities with recovery of about 50% of the chromosomes present in the metaphase cells. The method employs pressure homogenisation to release the chromosomes from the cells. The average chemical composition of the Microtus chromosome preparations is 24.6% DNA, 19.9% RNA and 55.5% protein. The isolated chromosomes were fractionated by sedimentation velocity in a density gradient into three size groups in one of which 75–80% of the chromosomes were the large sex-chromosomes. The relative composition of this fraction containing most of the heterochromatin of the cell was DNA: 100, RNA: 59, acid-soluble protein: 54, acid-insoluble protein: 178. — Disc electrophoresis studies revealed no significant difference in the histone patterns between the euchromatic and heterochromatic chromosomes of the three chromosome size-groups. Metaphase chromosomes appear to have a lower lysine-rich histone content than interphase nuclei.
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Skinner, L.G., Ockey, C.H. Isolation, fractionation and biochemical analysis of the metaphase chromosomes of Microtus agrestis . Chromosoma 35, 125–142 (1971). https://doi.org/10.1007/BF00285733
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DOI: https://doi.org/10.1007/BF00285733