Role of conserved sequence elements in yeast centromere DNA.

Area of Science:

• Molecular Biology
• Genetics
• Yeast Biology

Background:

• Centromere DNA (CEN DNA) in Saccharomyces cerevisiae contains conserved sequence elements essential for chromosome segregation.
• Understanding the precise boundaries and functional requirements of CEN DNA is crucial for comprehending mitotic and meiotic processes.

Purpose of the Study:

• To delineate the functional boundaries of Saccharomyces cerevisiae CEN DNA.
• To investigate the essentiality of specific conserved sequences and the intervening DNA region for centromere function.
• To assess the impact of CEN DNA integration into the genome.

Main Methods:

• Bal31 deletion analysis to define CEN DNA boundaries.
• Construction and analysis of CEN DNA mutants with altered length and GC content.
• Assessment of mitotic and meiotic segregation in plasmids carrying CEN mutations.
• Genomic integration of CEN DNA and analysis of gene tolerance.

Main Results:

• The left boundary of functional CEN DNA is defined by an 8 bp conserved sequence (PuTCACPuTG).
• The right boundary is within a 25 bp conserved region or slightly beyond.
• Deletion of the left conserved element results in a partially functional mitotic centromere and a functional meiotic centromere.
• Variations in length and GC content of the internal CEN DNA region do not affect segregation fidelity.
• Wild-type CEN6 DNA is tolerated when integrated 3' of the LYS2 gene.

Conclusions:

• The core functional unit of CEN DNA is defined by specific terminal conserved sequences.
• The internal DNA sequence between these elements is flexible and may act as a hinge region.
• CEN DNA exhibits a degree of genomic integration tolerance.