Protocol for FRAP-based estimation of nuclear import and export rates in single yeast cells.

Here, we present a protocol for estimating nuclear transport parameters in single cells. We describe steps for performing four consecutive fluorescence recovery after photobleaching experiments, fitting the obtained data to an ordinary differential equations model, and statistical analysis of the fittings using a specialized R package. This protocol permits the estimation of import and export rates, nuclear or cytosolic fixed fractions, and total number of molecules.

rcell2: Microscopy-Based Cytometry in R.

This article describes a method for quantifying various cellular features (e.g., volume, curvature, total and sub-cellular fluorescence localization) of individual cells from sets of microscope images, and for tracking them over time-course microscopy experiments.

Modulation of transcription factor dynamics allows versatile information transmission.

Cells detect changes in their environment and generate responses, often involving changes in gene expression. In this paper we use information theory and a simple transcription model to analyze whether the resulting gene expression serves to identify extracellular stimuli and assess their intensity when they are encoded in the amplitude, duration or frequency of pulses of a transcription factor's nuclear concentration (or activation state). We find, for all cases, that about three ranges of input strengths can be distinguished and that maximum information transmission occurs for fast and high activation threshold promoters.

Characterization of cell-to-cell variation in nuclear transport rates and identification of its sources.

Nuclear transport is an essential part of eukaryotic cell function. Here, we present scFRAP, a model-assisted fluorescent recovery after photobleaching (FRAP)- based method to determine nuclear import and export rates independently in individual live cells. To overcome the inherent noise of single-cell measurements, we performed sequential FRAPs on the same cell.