2 research outputs found
Phosphorylation controls spatial and temporal activities of motor-PRC1 complexes to complete mitosis
Dissecting mechanisms of chromosomemicrotubule interaction in oocytes by new imaging tools
Chromosome alignment and orientation within the spindle in mitosis and meiosis are
determined by chromosome-microtubule interaction. Evidence suggests that within
the acentrosomal spindle the mechanism of chromosome positioning is different
from in mitotic spindle but its molecular bases are not well understood. I investigated
how chromosome-microtubule interactions position the chromosomes within the
spindle using Drosophila oocytes. I addressed the role and molecular mechanisms of
kinetochore and chromosome interaction with microtubules in this process.
I developed new live imaging reagents to observe dynamic chromosome-microtubule
interaction. Live imaging combined with inactivation of kinetochores in
oocytes revealed that kinetochore-microtubule attachment is required for three-step
chromosome positioning in Drosophila oocytes: de-congression, change of
orientation and re-congression.
Augmin, a γ-tubulin recruiting complex, has been previously shown to be
important for chromosome congression specifically in oocytes. Live imaging further
showed that Augmin facilitates chromosome congression particularly in early stages
of spindle assembly. Study of Augmin dynamics revealed that Augmin stably
associates with spindle polar regions, specifically in oocytes. This meiotic regulation
of Augmin function may contribute to generation of force pushing chromosomes
toward spindle equator.
Sentin protein has been shown to be important for microtubule plus end
dynamics in mitosis. In meiosis, sentin mutant results in reduced distance between
centromeres of homologous chromosomes. However, its meiotic role is unknown.
Live imaging of the sentin mutant showed that in oocytes Sentin is required for
preventing premature stabilization of kinetochore-microtubule attachments.
As conclusion, I have used live imaging to reveal molecular basis of the
interaction between chromosomes and microtubules particularly important for
oocytes