Trypanosoma cruzi PARP is enriched in the nucleolus and is present in a thread connecting nuclei during mitosis

Area of Science:

• Cell Biology
• Molecular Biology
• Parasitology

Background:

• Poly (ADP-ribose) polymerase (PARP) regulates critical cellular processes including DNA repair and cell cycle progression.
• The only known PARP in Trypanosoma cruzi (TcPARP) was previously shown to enter the nucleus upon genotoxic stress.

Purpose of the Study:

• To identify the specific domain responsible for TcPARP nuclear localization.
• To investigate the sub-nuclear localization and mitotic behavior of TcPARP in T. cruzi.
• To explore potential novel functions of TcPARP beyond DNA damage response.

Main Methods:

• Domain analysis to determine nuclear localization signals.
• Immunofluorescence microscopy to visualize TcPARP localization within T. cruzi cells.
• Co-localization studies with nucleolar markers and microtubules during mitosis.

Main Results:

• The N-terminal domain of TcPARP was found to be sufficient for its nuclear import.
• TcPARP was observed to be enriched in the parasite's nucleolus.
• A novel thread-like structure containing TcPARP, nucleolar material, and microtubules was identified connecting two dividing nuclei during mitosis.
• ADP-ribose polymers were detected within this mitotic thread.

Conclusions:

• The N-terminal domain is crucial for TcPARP's nuclear targeting in T. cruzi.
• TcPARP exhibits specific localization within the nucleolus and a unique structure during cell division.
• These findings suggest new roles for TcPARP in the nucleus, potentially related to mitosis and nucleolar function, extending beyond its known DNA damage response role in trypanosomatids.