Biomedical subjects

Jedidiah Gaetz

Publications and source records attributed to Jedidiah Gaetz.

4 recordsLinked to original sources

PubMed2006

Examining how the spatial organization of chromatin signals influences metaphase spindle assembly.

During cell division, the proper assembly of a microtubule-based bipolar spindle depends on signals from chromatin. However, it is unknown how the spatial organization of chromatin signals affects spindle morphology. Here, we use paramagnetic chromatin beads, and magnetic fields for their alignment in cell-free extracts, to examine the spatial components of signals that regulate spindle assembly. We find that for linear chromatin-bead arrays that vary by eightfold in length, metaphase spindle size and shape are constant. Our findings indicate that, although chromatin provides cues for microtubule formation, metaphase spindle organization, which is controlled by microtubule-based motors, is robust to changes in the shape of chromatin signals.

Animals↗

PubMed2004

Par6alpha signaling controls glial-guided neuronal migration.

Neuronal migrations along glial fibers provide a primary pathway for the formation of cortical laminae. To examine the mechanisms underlying glial-guided migration, we analyzed the dynamics of cytoskeletal and signaling components in living neurons. Migration involves the coordinated two-stroke movement of a perinuclear tubulin 'cage' and the centrosome, with the centrosome moving forward before nuclear translocation. Overexpression of mPar6alpha disrupts the perinuclear tubulin cage, retargets PKCzeta and gamma-tubulin away from the centrosome, and inhibits centrosomal motion and neuronal migration. Thus, we propose that during neuronal migration the centrosome acts to coordinate cytoskeletal dynamics in response to mPar6alpha-mediated signaling.

Animals↗

PubMed2004

Dynein/dynactin regulate metaphase spindle length by targeting depolymerizing activities to spindle poles.

During cell division metaphase spindles maintain constant length, whereas spindle microtubules continuously flux polewards, requiring addition of tubulin subunits at microtubule plus-ends, polewards translocation of the microtubule lattice, and removal of tubulin subunits from microtubule minus-ends near spindle poles. How these processes are coordinated is unknown. Here, we show that dynein/dynactin, a multi-subunit microtubule minus-end-directed motor complex, and NuMA, a microtubule cross-linker, regulate spindle length. Fluorescent speckle microscopy reveals that dynactin or NuMA inhibition suppresses microtubule disassembly at spindle poles without affecting polewards microtubule sliding. The observed uncoupling of these two components of flux indicates that microtubule depolymerization is not required for the microtubule transport associated with polewards flux. Inhibition of Kif2a, a KinI kinesin known to depolymerize microtubules in vitro, results in increased spindle microtubule length. We find that dynein/dynactin contribute to the targeting of Kif2a to spindle poles, suggesting a model in which dynein/dynactin regulate spindle length and coordinate flux by maintaining microtubule depolymerizing activities at spindle poles.

Animals↗

PubMed2002

A zebrafish coxsackievirus and adenovirus receptor homologue interacts with coxsackie B virus and adenovirus.

In this study, a zebrafish homologue of the coxsackievirus and adenovirus receptor (CAR) protein was identified. Although the extracellular domain of zebrafish CAR (zCAR) is less than 50% identical to that of human CAR (hCAR), zCAR mediated infection of transfected cells by both adenovirus type 5 and coxsackievirus B3. CAR residues interacting deep within the coxsackievirus canyon are highly conserved in zCAR and hCAR, which is consistent with the idea that receptor contacts within the canyon are responsible for coxsackievirus attachment. In contrast, CAR residues contacting the south edge of the canyon are not conserved, suggesting that receptor interaction with the viral "puff region" is not essential for attachment.

Adenoviruses, Human↗