Spatial distribution patterns of interphase centromeres during retinoic acid-induced differentiation of promyelocytic leukemia cells.
BACKGROUND
The pericentromeric heterochromatin is an important element for the regulation of gene silencing. Its spatial distribution during interphase appears to be cell-type specific. This study analyzes three-dimensional (3D) centromere distribution patterns during cellular differentiation along the neutrophil pathway.


METHODS
Differentiation of the promyelocytic leukemia cell line NB4 was induced by retinoic acid. Centromeres in interphase nuclei were visualized by immunofluorescence staining of centromere-associated proteins with CREST serum. 3D images of nuclei were obtained by confocal microscopy. Automated methods for the segmentation of point-like objects in 3D images were implemented to detect the position of centromeres. Features of centromere localization patterns were determined by constructing the minimal spanning tree of the centromere distribution.


RESULTS
In differentiated NB4 cells, the number of centromere conglomerates (chromocenters) was decreased and the distance between chromocenters was increased as compared with untreated controls. The nuclear volume did not differ between the two groups.


CONCLUSIONS
The measured rearrangement of centromeres indicates a progressive clustering of heterochromatin and a global remodeling of interphase chromosome territories during differentiation of NB4 cells. The developed methods for the analysis of 3D centromere distribution patterns provide the opportunity for a fast and objective analysis of heterochromatin remodeling.
Beil
Michael
M
Department of Internal Medicine I, University Ulm, Ulm, Germany. michael.beil@medizin.uni-ulm.de
Dürschmied
Daniel
D
Paschke
Stephan
S
Schreiner
Bettina
B
Nolte
Ulla
U
Bruel
Arlette
A
Irinopoulou
Theano
T
D000465:Algorithms; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D016477:Artifacts; D002451:Cell Compartmentation / Q000187:drug effects / Q000235:genetics; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics*; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D002503:Centromere / Q000187:drug effects / Q000235:genetics* / Q000648:ultrastructure; D016193:G1 Phase / Q000187:drug effects / Q000235:genetics; D006098:Granulocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation / Q000379:methods; D007399:Interphase / Q000235:genetics*; D015473:Leukemia, Promyelocytic, Acute / Q000235:genetics* / Q000378:metabolism; D018613:Microscopy, Confocal / Q000295:instrumentation / Q000379:methods; D016011:Normal Distribution; D014212:Tretinoin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D000970:Antineoplastic Agents; D014212:Tretinoin