Nematode repetitive DNA with ARS and segregation function in Saccharomyces cerevisiae

Area of Science:

• Molecular Biology
• Genetics
• Developmental Biology

Background:

• The nematode Caenorhabditis elegans genome contains repetitive DNA families.
• Understanding the function of repetitive DNA is crucial for genome stability and replication.

Purpose of the Study:

• To investigate the potential replication and centromeric functions of the CeRep3 repetitive DNA family in C. elegans.
• To determine if CeRep3 elements can confer ARS and centromeric functions in a heterologous system.

Main Methods:

• Sequencing of three CeRep3 elements to identify homologous sequences to yeast ARS and CEN consensus sequences.
• Ligation of nematode DNA segments containing CeRep3 repeats to shuttle vectors.
• Introduction of engineered plasmids into yeast cells (Saccharomyces cerevisiae).
• Assessing ARS function by measuring transformation frequency.
• Evaluating centromeric (SEG) function by analyzing mitotic stability, meiotic segregation patterns, and plasmid copy number.

Main Results:

• CeRep3 elements contain DNA sequences homologous to yeast ARS and CEN consensus sequences.
• Nematode DNA segments with CeRep3 repeats conferred ARS function to plasmids in yeast, increasing transformation frequency.
• Some segments also conferred increased mitotic stability, altered meiotic segregation (2+:2-), and decreased plasmid copy number, mimicking yeast centromeric DNA functions.
• These functional similarities suggest a conserved role for these DNA elements.

Conclusions:

• The CeRep3 repetitive DNA family in C. elegans exhibits functional homology to yeast ARS and centromeric elements.
• These findings strongly suggest that the CeRep3 family plays a role in DNA replication and centromeric function within the nematode genome.
• Further research is warranted to confirm these functions in C. elegans.