Two proteins that cycle asynchronously between centrosomes and nuclear structures: Drosophila CP60 and CP190

Area of Science:

• Cell Biology
• Molecular Biology
• Developmental Biology

Background:

• The nucleus and centrosome are dynamic structures with cell cycle-dependent rearrangements.
• CP190 and CP60 are Drosophila proteins with unknown functions that cycle between centrosomes and nuclei.

Purpose of the Study:

• To investigate the cell cycle-dependent behavior and localization of CP190 and CP60 in living Drosophila embryos.
• To determine if CP190 and CP60 form distinct structures within the nucleus and centrosome.

Main Methods:

• Injection of fluorescently labeled CP190 and CP60 into living Drosophila embryos.
• Quantitative 3-D wide-field fluorescence microscopy to track protein dynamics during nuclear cycles 10-13.
• Analysis of protein localization and network formation during different cell cycle stages.

Main Results:

• CP190 and CP60 exhibit asynchronous cycling between nuclei and centrosomes, with CP190 accumulation preceding CP60.
• CP190 localizes to nuclei during interphase and centrosomes during mitosis, while CP60 accumulates at centrosomes during anaphase and in nuclei during interphase.
• Both proteins form distinct, coherent fibrous intranuclear networks that persist through mitosis, suggesting a potential nuclear skeleton.

Conclusions:

• CP190 and CP60 play dynamic roles in cell cycle progression, shuttling between the nucleus and centrosome.
• The formation of stable intranuclear networks by CP190 and CP60 provides evidence for a potential nuclear skeleton.
• Further research is needed to elucidate the precise functions of these proteins and their associated networks.