A 3D analysis tool for segmenting and measuring the structure of telomeres in mammalian nuclei

Abstract

We have developed a 3D analysis program, which we call Teloview, for segmentation and measurement of telomeres in the nucleus. Telomeres are the terminals of DNA with a repetitive (in vertebrates: TTAGGG) sequence between 3 and 20 kilobases in length. The slides with mammalian nuclei are prepared so, that the 3D structural information stays intact. After imaging the nucleus with a wide-field microscope, the 3D-image is deconvolved and loaded into Teloview. The operator can choose an algorithm to find the location of the telomeres. If there are false positives and/or false negatives, the operator can interactively correct this. At this point the program can measure two features: the a/c-ratio of the telomeres and the 3D integrated intensity. The telomeres seem to be in a territory which has the form of an oblate sphere (a spheroid). Such a spheroid has three principle axes, which we call a, b and c. Because the spheroid is oblate, a = b and a > c. So the ratio a / c, is an indication of the flatness of the spheroid. It has been shown that the intensity of the telomeres is proportional to the length of the telomeres. Using these two features, Teloview has been used in studies where structural information and length measurements of telomeres are necessary. Since Teloview is developed in MatLab using the Delft Image Processing toolbox (DIPimage) new measurement features can be easily incorporated and tested.