The localization of chromosome domains in human interphase nuclei. Semi-automated two-dimensional image acquisition and analysis of fluorescence in situ hybridization signals

Two-dimensional fluorescence images were used to determine the localization of in situ hybridization signals from two centromeric DNA probes within human fibroblasts as a function of the cell cycle. The probes were specific for the centromeres of chromosomes 7 and 15. A high resolution CCD camera combined with image processing software allowed a semi-automated quantitation of the data, which were analysed statistically. It was found that the distances of centromere 15 to the nuclear membrane were significantly greater than those of centromere 7, the distribution of which was random in cycling cells. The distances between the homolog 15 centromeres were smaller than between the homolog 7 centromeres. In addition, both centromeric probes showed the largest deviation from a random orientation in the G₀ resting state of the cell cycle. The more central location of centromere 15 may reflect the localization of the nucleolus organizing region of this chromosome and the corresponding location of nucleoli in human fibroblasts. The methods used to acquire and process the data are well suited to the semi-automated analysis of fluorescence in situ hybridization (FISH) signals for the cytogenetic analysis of normal and pathologic tissue.