Chromosome stability is maintained by short intercentromeric distance in functionally dicentric human Robertsonian
1Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
Summary
Dicentric Robertsonian translocations are usually stable due to centromere inactivation. This study found that centromere protein C (CENP-C) presence at one centromere suggests inactivation, contributing to stability in these human chromosome translocations.
Area of Science:
- Genetics
- Cell Biology
- Molecular Biology
Background:
- Dicentric chromosomes typically cause instability.
- Human dicentric Robertsonian translocations (rob(13q14q)) are an exception, exhibiting stability.
- The mechanisms underlying this stability require further investigation.
Purpose of the Study:
- To investigate the centromere function and stability of human dicentric Robertsonian translocations.
- To determine if centromere inactivation contributes to the stability of rob(13q14q) translocations.
Main Methods:
- Examined 15 cases of structurally dicentric rob(13q14q) Robertsonian translocations.
- Utilized immunofluorescence and fluorescence in situ hybridization (FISH).
- Assessed centromere function using centromere protein C (CENP-C) as a marker.
Main Results:
- CENP-C was detected on only one centromere in a fraction of cells, indicating inactivation.
- In 12 out of 15 translocations, a subset of cells showed CENP-C at both centromeres, suggesting functional dicentricity.
- The percentage of cells with dual CENP-C labeling varied significantly (2%–82%).
Conclusions:
- Centromere inactivation is a common mechanism contributing to the stability of dicentric Robertsonian translocations.
- The close proximity of two active centromeres in some cells suggests they can remain stable despite functional dicentricity.
- These findings provide insight into the molecular basis of Robertsonian translocation stability.
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