BIGGINS LAB

Welcome to the Biggins Lab

How Do Cells Get the Right Chromosomes?

The generation and survival of all organisms depends on the faithful execution of cell division. A complete understanding of the regulation and controls over cell division is critical to elucidate the mechanisms that govern self-renewal, proliferation and development. A key event in the cell cycle is the precise partitioning of every pair of duplicated chromosomes to daughter cells. Defects in segregation lead to aneuploidy, the state where entire chromosomes are gained or lost. Aneuploidy is a hallmark of most tumor cells and has been postulated to be a major factor in the evolution of cancer. It is also the leading cause of spontaneous miscarriages and hereditary birth defects in humans. Our goal is to understand the mechanisms that ensure accurate chromosome segregation and thus maintain genomic stability and prevent human disease. This work is critical not only for elucidating fundamental aspects of this essential biological process, but is also required for the design of better therapeutic interventions in the long-term.

Chromosome segregation is directed by the kinetochore, the macromolecular protein structure that assembles onto centromeric chromatin. The kinetochore binds to the microtubules that compose the mitotic spindle and physically pulls chromosomes into daughter cells. If there are defects in kinetochore-microtubule attachments or the tension generated by microtubule pulling forces, the spindle checkpoint halts the cell cycle. It is essential that every chromosome assemble a single kinetochore on centromeric chromatin during every cell cycle. Our lab is taking a comprehensive approach to understanding the assembly, functions and architecture of the kinetochore and the underlying specialized centromeric chromatin.

We recently developed a technique to purify native kinetochores from budding yeast and are now exploring the following key questions:

  • What is the architecture of the macromolecular kinetochore complex?
  • How is the spindle checkpoint activated and silenced by tension and attachment at kinetochores?
  • How is the underlying specialized chromatin assembled and maintained exclusively at the centromere on each chromosome?
  • How are kinetochore-microtubule attachments made and regulated?
  • How do kinetochores assemble to carry out their complex functions?

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IN THE NEWS:

Biggins Lab article featured in Stanford University Yeast Genome article

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The kinetochores are the loci on the chromosomes that attach to microtubules. Once every pair of sister chromatids attaches to microtubules from opposite poles at metaphase, the cells initiates anaphase and the microtubules pull the chromosomes to the poles.