Welcome to the lean, mean website of the
Bloom Lab, where we do exciting things with yeast.
Below you can find a representative sample of some of our
recent work. For a more comprehensive summary of our work, most of our publications are available for downloading.
- Determining the structure of
pericentric DNA and cohesin in
the inner centromere. Pericentric
chromatin is organized by cohesin
into a cylinder surrounding the interpolar microtubules of the mitotic
We are testing whether centromere flanking DNA is paired
the inner centromere cruciform, and whether the structure of the
inner centromere and the cohesin cylinder is responsive to changes in
requirements for cohesin cylinder formation and maintenance and
identify how cohesin is restricted to pericentric chromatin. We will
determine the requirements for cohesin cylinder
formation, and test the hypothesis that specific proteins restrict
the 30-50kb of pericentric chromatin. We propose that the transition
arm pairing and pericentric chromatin provides the structural basis for
sensing in the inner centromere.
Images from left to right: Computer generated mitotic
spindle viewed end on, an end on view of SMC3-GFP, computer generated
mitotic spindle viewed side on, and a side on view of SMC3-GFP.
Flourescent microscopy reveals that cohesin (SMC3) forms a hollow
cylindrical structure between the kinetochores (images not shown). This
data matches the predictions made by our model for the organization of
the mitotic spindle - the chromosomes (represented by orange and red
coils) and kinetochore microtubules (light green rods) are arranged in a cylinder
around a core of interpolar microtubules (dark green rods).
the proposal that the conserved chromosome segregation unit is the
pericentric cruciform. We will count the number of
kinetochore proteins at the microtubule interface in distantly related
yeasts. This analysis will reveal whether point vs. regional
centromeres have structurally conserved features.
- Examining the physical contributions of the DNA to the
mitotic spindle. In particular, we are interested in the potential
spring-like properties of DNA, and the tension this applies to the
spindle. One approach is to look at the recoil of DNA strands after
breakage, both in vivo and in vitro. The following movie is an example
DNA breakage and recoil in vivo.
LacO tagged with LacI-GFP
how the state of tension of pericentric chromatin is transmitted to the
kinetochore DNA linkage to regulate microtubule attachment. We will
determine the sites within the kinetochore and pericentric chromatin
that are tension-sensitive and identify specific linkages that are
compliant. We will use single molecule analysis in live yeast to
identify the molecular basis of pericentric chromatin and kinetochore
extension and contraction upon change in force.