Date of Award

1-1-2012

Document Type

Thesis

Degree Name

M.S.

Department

Physics and Astronomy

First Advisor

Dinah Loerke

Abstract

Motion of particles under influencing forces may be observed under light microscopy techniques. Variations in mobility of particles may give relevant biophysical information. Automated high resolution single particle tracking techniques were used to characterize interphase chromatin mobility in the cell nucleus. Interphase chromatin undergo replication prior to cell division with the assistance of replication proteins (machinery) which modify chromatin mobility. Using dual color imaging of flourescently tagged chromatin and proliferating cell nuclear antigen (PCNA) were followed through interphase. Chromatin motion was modelled as a two dimensional random walk. Reduction in chromatin mobility was observed during S phase was dependent on proximity to the replication machinery. Mobility during G1 and G2 phase is independent of proximity to GFP-PCNA maxima and is higher than during S phase. These results suggest that replication selectively inhibits chromatin mobility. Local proximity to replication machinery however, cannot account for the entire mobility difference. By modelling the mean square displacement as a power law, sub-diffusive behavior was observed in S phase chromatin whereas non S phase exhibited normal diffusional characteristics.

Provenance

Recieved from ProQuest

Rights holder

Matthew Joel Westacott

File size

46 p.

File format

application/pdf

Language

en

Discipline

Biophysics

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