Poly (ADP-ribose) polymerase in yeasts: characterization and involvement in telomere maintenance

Area of Science:

• Molecular Biology
• Biochemistry
• Yeast Genetics

Background:

• Poly (ADP-ribose) polymerases (PARPs) are vital enzymes in eukaryotic DNA repair and maintenance.
• PARP homologs were previously undiscovered in ascomycetous yeasts, leaving their functions unexplored.
• Yarrowia lipolytica is a non-conventional yeast with unique biological characteristics.

Purpose of the Study:

• To identify and characterize the first PARP enzyme in yeasts.
• To investigate the function of the candidate PARP, Pyl1, in Yarrowia lipolytica.
• To explore the role of Pyl1 in telomere maintenance and DNA repair pathways.

Main Methods:

• Gene expression analysis of PYL1 in telomerase-deficient mutants.
• Identification of Pyl1 protein targets using in vivo assays.
• Biochemical assays to demonstrate Pyl1 enzymatic activity (auto-PARylation and PARylation of YlKu70/80).
• Analysis of YlKu80 localization upon PYL1 overexpression.

Main Results:

• PYL1 gene expression is upregulated in yeast mutants lacking telomerase subunits.
• Pyl1 protein is a functional PARP, exhibiting auto-PARylation and PARylating the YlKu70/80 complex.
• Overexpression of PYL1 leads to the dissociation of YlKu80 from telomeres.
• Several candidate protein targets for Pyl1 were identified in vivo.

Conclusions:

• Pyl1 is the first identified yeast PARP, playing a role in telomere protection and maintenance.
• Pyl1 functions in DNA repair pathways, potentially interacting with the YlKu70/80 complex.
• Pyl1 and its homologs represent a distinct class of PARPs warranting further investigation in yeast species.