Unequivocal identification of the active and inactive centromere of a dicentric chromosome by simultaneous CENP-C immunofluorescence and FISH
- Baylor College of Medicine, Houston, TX (United States)
- Johns Hopkins Univ. School of Medicine, Baltimore, MD (United States); and others
There have been many reports of stable dicentric chromosomes resulting from translocations in humans. The stability of these chromosomes has been attributed to the inactivation of one centromere, yielding a functionally monocentric chromosome. We ascertained a patient with the karyotype 45,X/45,X,der(X)t(X;15)(Xpter{yields}Xq26::15p11{yields}15qter). The derivative chromosome was apparently dicentric by G-band analysis. A primary constriction at the X centromere and lack of a constriction corresponding to the 15 centromere suggested that the 15 centromere was inactive, while the X centromere remained active. Centromere Protein C(CENP-C) is normally present at all human centromeres and is localized to the inner kinetochore plate. Previous immunofluorescence studies of a stable isodicentric chromosome showed CENP-C to be present at the active centromere, while no staining was observed at the inactive centromere. By combining immunofluorescence detection of CENP-C and multi-color fluorescence in situ hybridization (FISH) with chromosome-specific {alpha} satellite DNA probes, we have unequivocally identified the active centromere in the (X;15) translocation. Metaphases were prepared by cytocentrifugation of hypotonically swelled lymphoblasts. Indirect immunofluorescence, performed using polyclonal rabbit antiserum raised against CENP-C, and FISH with {alpha}-satellite probes specific for the centromeres of chromosomes 15 (pTRA-20,pTRA-25) and X (DXZ1) revealed CENP-C immunofluorescence signals at the X {alpha}-satellite probe, with no CENP-C detected at the 15 centromere on the translocation in this cell line. This study is the first to demonstrate the specificity of CENP-C to the active centromere in a nonhomologous dicentric rearrangement and further establishes CENP-C as an essential component of a functional human centromere.
- OSTI ID:
- 133411
- Report Number(s):
- CONF-941009--
- Journal Information:
- American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: Suppl.3 Vol. 55; ISSN AJHGAG; ISSN 0002-9297
- Country of Publication:
- United States
- Language:
- English
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