Tissue inducible Lifeact expression allows visualization of actin dynamics in vivo and ex vivo

• Published in: European journal of cell biology Vol. 91; no. 11-12; pp. 923 - 929
• Main Authors: Schachtner, Hannah, Li, Ang, Stevenson, David, Calaminus, Simon D.J., Thomas, Steven G., Watson, Steve P., Sixt, Michael, Wedlich-Soldner, Roland, Strathdee, Douglas, Machesky, Laura M.
• Format: Journal Article
• Language: English
• Published: Germany Elsevier GmbH 01-11-2012
• Subjects: Actin Cytoskeleton - ultrastructure; Actin dynamics; Actins - genetics; Actins - metabolism; Animals; Cell Line; Cell migration; Cell Movement; Cytokinesis; Cytoskeleton; Gene Expression Regulation; Genes, Reporter; Green Fluorescent Proteins - genetics; Imaging; Melanocytes - metabolism; Melanocytes - ultrastructure; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microscopy, Fluorescence; Motility; Neural Stem Cells - metabolism; Neural Stem Cells - ultrastructure; Neuropeptides - genetics; Neuropeptides - metabolism; Organ Specificity; Peptides - genetics; Pseudopodia - metabolism; rac GTP-Binding Proteins - genetics; rac GTP-Binding Proteins - metabolism; rac1 GTP-Binding Protein; Recombinant Proteins - genetics; Time-Lapse Imaging; Transcription, Genetic; Cytoskeleton; Motility; Cytokinesis; Actin dynamics; Imaging; Cell migration
• ISSN: 0171-9335; 1618-1298
• DOI: 10.1016/j.ejcb.2012.04.002

We describe here the development and characterization of a conditionally inducible mouse model expressing Lifeact-GFP, a peptide that reports the dynamics of filamentous actin. We have used this model to study platelets, megakaryocytes and melanoblasts and we provide evidence that Lifeact-GFP is a useful reporter in these cell types ex vivo. In the case of platelets and megakaryocytes, these cells are not transfectable by traditional methods, so conditional activation of Lifeact allows the study of actin dynamics in these cells live. We studied melanoblasts in native skin explants from embryos, allowing the visualization of live actin dynamics during cytokinesis and migration. Our study revealed that melanoblasts lacking the small GTPase Rac1 show a delay in the formation of new pseudopodia following cytokinesis that accounts for the previously reported cytokinesis delay in these cells. Thus, through use of this mouse model, we were able to gain insights into the actin dynamics of cells that could only previously be studied using fixed specimens or following isolation from their native tissue environment.