Quantification of junction formation. Control and Apg-2 RNAi cells were cultured and processed as described in figure 3. Junction formation was allowed to proceed for the indicated amount of time (A) or for one hour (B). The cells were then stained for either ZO-1 (A) or f-actin, occludin, claudin-4, cingulin, GEF-H1, α-catenin or E-cadherin (B). The fractions of cells expressing the labelled markers along the entire lateral cell membrane were then determined by counting. At least five different fields derived from two independent experiments were counted for each marker and time point. Note, as a large fraction of claudin-4 is continuously at the plasma membrane even before the addition of calcium, its early presence at the plasma membrane does not indicate tight junction formation.
Aijaz et al. BMC Cell Biology 2007 8:49 doi:10.1186/1471-2121-8-49