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Centromere DNA mutations induce a mitotic delay in Saccharomyces cerevisiae
1Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185.
Summary
Centromere DNA mutations in yeast cause significant cell cycle delays, slowing mitosis. This delay may stabilize chromosomes with faulty attachments, suggesting a checkpoint mechanism.
Area of Science:
- Cell Biology
- Genetics
- Molecular Biology
Background:
- Mitotic delays occur in animal cells when chromosome attachment to the spindle is impaired.
- Understanding cell cycle regulation is crucial for comprehending cell division fidelity.
Purpose of the Study:
- To investigate if centromere DNA (CEN) mutations can induce cell cycle delays in yeast (Saccharomyces cerevisiae).
- To characterize the mitotic delay phenotype caused by specific CEN DNA mutations.
Main Methods:
- Introduction of a 31-base-pair deletion in centromere DNA element II (CDEII delta 31) in yeast.
- Analysis of cell division and pedigree of yeast strains with CEN DNA mutations.
- Synchronous cell population studies to assess DNA synthesis and cell separation timing.
Main Results:
- A CDEII delta 31 CEN mutation, causing 1% chromosome missegregation, induced a dramatic mitotic delay.
- Other CEN DNA mutations (elements I and III) also delayed mitosis.
- Synchronous yeast cells with CDEII delta 31 showed normal DNA synthesis but delayed chromosomal and cell separation.
Conclusions:
- Centromere DNA mutations can trigger significant cell cycle delays before anaphase onset in yeast.
- This delay may serve as a mechanism to stabilize chromosomes with defective kinetochore structures.
- The observed delay suggests a cell cycle checkpoint monitoring chromosome-spindle attachment completion.