Telomere Disruption Results in Non-Random Formation of De Novo Dicentric Chromosomes Involving Acrocentric Human Chromosomes (original) (raw)
Figure 7
Dicentric stability is associated with chromosomal fragments.
(A) The appearance of small chromosome fragments either containing or lacking CENP-A (green) and CENP-B (red) was monitored over time, from the time of dicentric formation (40h) to 20 weeks. Arrowheads denote chromosome fragments. The DAPI image is shown in the middle panel. Combined CENP-A (green) and CENP-B (red) is shown in the far right panel. (B) At 16 weeks after formation of an irob(13;14), immunostaining for CENP-A followed by FISH with chromosome-specific α-satellite probes revealed that CENP-A did not co-localize with CEN13 (arrow; see enlargement of centromeric region). A small CEN13 fragment that was CENP-A-positive (arrowhead; see enlargement of CENP-A/α-satellite signal of fragment) was present in the same cell. This chromosomal fragment was hypothesized to have originated from the inactivated CEN13 of the iROB. (C) Chromosomal fragments, with and without CENP-A and acrocentric α-satellite DNA was monitored over time. CENP-A-positive chromosome fragments (black+dark gray bars), many of which corresponded to acrocentric α-satellite DNA (dark gray), were prevalent after dicentric formation. These fragments decreased after 20 weeks, suggesting that they were lost during cell division. Thirty to 270 cells per time point were analyzed.