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Updated: Oct 26, 2026
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Published on: October 11, 2022
The MCM16 gene of the yeast Saccharomyces cerevisiae is required for chromosome segregation
Abstract:
We have cloned and characterized the MCM16 gene required for the maintenance of minichromosomes in the yeast Saccharomyces cerevisiae. This gene corresponds to a 181-amino acid ORF, YPR046W, on chromosome XVI. Mutant cells carrying minichromosomes accumulate them in higher copy numbers than do wild-type cells. Intact dicentric plasmid could be recovered from the mutant, in contrast to the wild-type, in which the plasmid suffered frequent deletions. A wild-type centromere, CEN6, acts as a block to the transcription of a reporter gene, such as beta-galactosidase. This block was less effective in the mutant than in the wild-type strain, suggesting alterations in kinetochore assembly in the former. The mutant also showed increased sensitivity to the antimitotic drugs benomyl and thiabendazole. The mcm16 mutation caused a high rate of loss of chromosome III, without any significant increase in the recombination frequency. A strain carrying a deletion-disruption derivative of the MCM16 gene was viable and, when compared to the wild-type, did not show any significant changes in growth rate or cell morphology at 16, 23 and 37 degrees C. These properties show that MCM16 is required for an important but nonessential role that governs the kinetochore-microtubule mediated process of chromosome segregation.
Insights
The MCM16 gene in yeast is crucial for maintaining minichromosomes and proper chromosome segregation. Mutations in MCM16 disrupt kinetochore assembly, leading to chromosome instability and drug sensitivity.
Area of Science:
- Molecular Biology
- Genetics
- Cell Biology
Background:
- Minichromosome maintenance is essential for genetic stability in eukaryotic cells.
- The kinetochore is a complex protein structure responsible for chromosome segregation during cell division.
- Understanding genes involved in these processes is key to deciphering mechanisms of genome integrity.
Purpose of the Study:
- To clone and characterize the MCM16 gene in Saccharomyces cerevisiae.
- To investigate the role of MCM16 in minichromosome maintenance and chromosome segregation.
- To elucidate the function of MCM16 in kinetochore assembly and function.
Main Methods:
- Gene cloning and characterization of the MCM16 open reading frame (ORF).
- Analysis of minichromosome copy number and stability in mcm16 mutant strains.
- Assessment of plasmid integrity and reporter gene transcription in wild-type and mutant cells.
- Evaluation of sensitivity to antimitotic drugs and chromosome loss rates.
Main Results:
- MCM16 is identified as YPR046W on chromosome XVI, encoding a 181-amino acid protein.
- Mutations in MCM16 lead to increased minichromosome copy number and frequent plasmid deletions.
- MCM16 mutants exhibit impaired centromere function, affecting reporter gene transcription.
- The mcm16 mutation results in high chromosome III loss rates and increased sensitivity to benomyl and thiabendazole.
- Deletion-disruption of MCM16 does not affect cell viability, growth rate, or morphology.
Conclusions:
- MCM16 plays a critical role in minichromosome maintenance and accurate chromosome segregation.
- The MCM16 gene product is involved in kinetochore assembly and function.
- MCM16 governs the kinetochore-microtubule mediated process of chromosome segregation.
- MCM16 is essential for an important but nonessential role in yeast cell division.
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