Research
Research
In the Nannas lab, we are focused on understanding how chromosomes are properly segregated during meiosis, the specialized cell division that produces gametes. Errors in meiosis can lead to miscarriage, infertility, and genetic disorders. We are interested in pathways that govern the assembly of the spindle, the machinery used to pull chromosomes apart, the structures that attach chromosomes to the spindle, and the mechanisms used to ensure accurate chromosome segregation.
Meiotic spindle assembly
Spindles consist of many microtubules that must be organized into a bipolar structure. In mitotic spindles, the assembly process is regulated by centrosomes that direct microtubule nucleation and organization. Meiotic cells, however, lack these structures, and spindle assembly is self-directed through less understood pathways. We are interested in the dynamics of spindle assembly, chromosome segregation, and later events including spindle disassembly and phragmoplast expansion.
Chromosome-spindle interactions
We are interested in how chromosomes attach to the spindle, and how cells monitor these attachments. Large protein structures called kinetochores bind to chromosomes and serve as a bridge to connect them to microtubules in the spindle. We are investigating the composition, structure, and function of kinetochores in Zea mays. We are also interested in the spindle checkpoint, a mechanism that monitors the attachment of microtubules to kinetochores and ensures proper chromosome segregation.
Selfish chromosomes
The segregation of chromosomes during meiosis is an unbiased process that leads to predictable patterns of inheritance. A selfish chromosome called Abnormal Chromosome 10 was discovered in maize that can break these laws of inheritance. We are investigating how this chromosome can drive its own inheritance through specialized motors called kinesins.