Generation of Intestinal Epithelial β-Actin Knockout Mice

In order to establish a conditional knockout of β-actin in the intestinal epithelium, Actb ^flox/flox mice on a C57BL/6 background (Sonnemann et al., 2006 (link); Perrin et al., 2010 (link)) were crossed with villin-Cre animals (Jackson Laboratory, stock # 004586). In these villin-Cre mice, a 12.4 kb fragment of mouse villin 1 promoter directs Cre recombinase expression in both the small intestine and the colon (Madison et al., 2002 (link)). The animal colony was maintained under pathogen-free conditions in the vivarium of Virginia Commonwealth University Medical Center and then Lerner Research Institute of Cleveland Clinic. The mouse room was on a 12 h light/dark cycle and standard feed and tap water were available, ad libitum. At the beginning of colitis experiments, mice weighed 18–25 g, with no significant difference between the body masses of mice of different genotypes. All procedures were conducted under animal research protocols approved by the Virginia Commonwealth University and Lerner Research Institute Animal Care and Use Committees in accordance with the National Institutes of Health Animal Care and Use Guidelines.