Telomeric repeat organization—a comparative in situ study between man and rodent

Abstract

Human, hamster, and mouse chromosomes show both similarities and differences in telomeric organization, detectable with a novel version of the PRINS technique. The differences allowed us to investigate the fate of the telomeres on a chromosome from one species when this chromosome was introduced into the cells of another species. For this purpose, we tested telomeres in cell lines of somatic cell hybrids containing human chromosomes on a rodent background, finding that the telomeres on human chromosomes could not be discriminated from the telomeres on rodent chromosomes. All telomeres in the cell lines were much shorter than the telomeres in normal cells. In the mouse-derived cell lines, half of the mouse chromosomes were fused to other mouse chromosomes at the ends of their short arms. At the points of fusion we were generally unable to detect telomeric signals. In these cell lines, we also found a fraction of chromosomes ends with only one telomeric signal. In chromosomes where both ends showed only one signal, the relative orientation of the signals appeared to be nonrandom with respect to sister chromatids.

Two mosaic terminal inverted duplications arising post-zygotically: Evidence for possible formation of neo-telomeres

“…It is reasonable to ask whether there is any evidence for such delayed repair in other chromosome rearrangement types since a broken chromosome/DNA molecule is known to be unstable due to "sticky ends". A classic example of this "stickyness" is seen in specific cell lines or tumour types where telomeres have been reported to be very reduced or absent and chromosome end-to-end chains tend to form [ 18 ].…”

Limitations to the Development of Humanized Antibody Producing Chinese Hamster Ovary Cells Using Glutamine Synthetase-Mediated Gene Amplification

“…Dual‐color FISH was performed to co‐localize amplified sequences and telomeric repeat sequences. Telomeric repeat sequences, (TTAGGG) n , were first stained by the primed in situ labeling (PRINS) technique as described previously (15). The slides containing the fixed metaphase chromosomes were prepared just before the PRINS reaction.…”

Principles and Applications of PRINS in Cytogenetics

“…Staining of very small target sequences has been employed for the study of variant telomeric repeats at individual chromosome ends in a variety of species. Furthermore, since one strand of the target is flanked at its 5′‐end by one sequence, and the other strand by another, it is possible to also determine the orientation of the target—for example, the relative orientation of various telomeric repeat variants with respect to each other—by this method (Krejci and Koch, ; Serakinci and Koch, ; Serakinci et al, ).…”

“…Consequently, what is obtained is a uniquely sensitive detection of simple repeat DNA, including telomeric repeats and trinucleotide repeats (Serakinci and Koch, ), with a labeling intensity reflecting the amount of target sequence at a particular site (Q‐PRINS; Krejci and Koch, ). Combining this with the high discriminatory power of the PRINS technique, it is possible to selectively detect and measure small closely related sequence elements and to study their organization (Krejci and Koch, ; Serakinci et al, ). Staining of very small target sequences has been employed for the study of variant telomeric repeats at individual chromosome ends in a variety of species.…”