A maternal effect rough deal mutation suggests that multiple pathways regulate Drosophila RZZ kinetochore recruitment

Area of Science:

• Cell Biology
• Genetics
• Molecular Biology

Background:

• The Rod-Zw10-Zwilch (RZZ) complex is crucial for kinetochore function, regulating dynein and the Mad1-Mad2 complex.
• Proper kinetochore recruitment ensures accurate chromosome segregation during cell division.

Purpose of the Study:

• To investigate the role of a specific mutation in the Rod subunit of the RZZ complex.
• To understand the impact of this mutation on RZZ complex recruitment and spindle assembly checkpoint (SAC) function in Drosophila.

Main Methods:

• Characterization of a novel Drosophila mutation, rod(Z3), affecting the Rod subunit.
• Analysis of RZZ complex localization and SAC activity in syncytial embryos and larval neuroblasts.
• Assessment of kinetochore recruitment dynamics and interactions with microtubule-dependent motors.

Main Results:

• The rod(Z3) mutation prevents RZZ complex kinetochore recruitment in early syncytial embryos, leading to SAC defects and mitotic abnormalities.
• In larval neuroblasts, RZZ recruitment is partially reduced, the SAC remains functional, but RZZ exhibits altered kinetochore behavior.
• The mutated Rod subunit interferes with Mad1 recruitment and dynein-mediated RZZ displacement from kinetochores.

Conclusions:

• The mutated residue in Rod(Z3) is essential for normal RZZ kinetochore recruitment and function.
• The RZZ complex recruitment pathway may differ between early embryonic and post-embryonic somatic cells in Drosophila.