Research: Lab Papers

Performing 2D dynamic measurements in vivo using Fluorescence Correlation Spectroscopy

Anand Singh, a post-doc in the lab, has recently published a Nature Protocols article [16] detailing how to perform 2D fluorescence correlation spectroscopy. This work was done in collaboration with Thorsten Wohland at NUS and Jorg Langowski in Germany.

Using all the information: temporal and spatial information from morphogen gradients

In collaboration with Dr David Richards at Imperial college London, I have performed a detailed spatiotemporal analysis of different mechanisms for interpreting morphogen gradients. In particular, we determine how accurately the spatial and temporal derivatives of the morphogen gradient can be interpreted. We use this to demonstrate that a morphogen can be used to define a temporal switch as well as spatial positions.

Protein aggregation may help single cells reliably produce subcellular gradients

Most models of chemical gradient formation assume that the diffusion of the components is unchanged by the chemical concentration. However, there is evidence, particularly from the pom1p gradient in fission yeast (see Previous Work), that clustering may play an important role in chemical gradient formation. By clustering, the dynamics of the diffusing molecule are altered and this can impact on the robustness of the resulting gradient. I have published a detailed theoretical analysis of a model of gradient formation via clustering and shown that precise gradients can be formed [13]. Using biophysical arguments the model consisted of only two free parameters to define the complex process of clustering and gradient formation.

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Cluser size as function of position for a subcellular gradient, where the coloring corresponds to the total protein concentration (adapted from [13])


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Mounting protocol for FCS imaging (top) and FCS readings from a Drosophila embryo expressing histone-RFP (adapted from [16])