Using Drosophila Genetics to Identify Factors that Affect PARP1 Activity In Vivo.

PARP1 is the enzyme responsible for the majority of the poly(ADP-ribose) (pADPr) synthesis in Drosophila. Its activity can be easily evaluated in vitro by measuring the level of pADPr, which allow to study the effect of potential PARP1 upstream factors on PARP1 activity. However, PARP1 activity can be challenging to measure in vivo, due to the presence of PARG, since pADPr level is a consequence of the activity of both PARP1 that synthetizes pADPr and PARG that degrades it. An increase in PARG activity can hide an increase of PARP1 activity. In this context, the effect of potential upstream factors on PARP1 activity can be hard to measure. Here, we describe a genetic background where PARG is absent to study changes in PARP1 activity at different developmental time points.