Real-time imaging of integrin β4 dynamics using a reporter cell line generated by Crispr/Cas9 genome editing

The ability to monitor changes in the expression and localization of integrins is essential for understanding their contribution to development, tissue homeostasis and disease. Here, we pioneered the use of Crispr/Cas9 genome editing to tag an allele of the beta 4 subunit of the alpha 6 beta 4 integrin. A td Tomato tag was inserted with a linker at the C-terminus of integrin beta 4 in mouse mammary epithelial cells. Cells harboring this tagged allele were similar to wild-type cells with respect to integrin beta 4 surface expression, association with the alpha 6 subunit, adhesion to laminin and consequent signaling. These integrin beta 4 reporter cells were transformed with YAP (also known as YAP1), which enabled us to obtain novel insight into integrin beta 4 dynamics in response to a migratory stimulus (scratch wound) by live-cell video microscopy. An increase in integrin beta 4 expression in cells proximal to the wound edge was evident, and a population of integrin beta 4-expressing cells that exhibited unusually rapid migration was identified. These findings could shed insight into integrin beta 4 dynamics during invasion and metastasis. Moreover, these integrin beta 4 reporter cells should facilitate studies on the contribution of this integrin to mammary gland biology and cancer. This article has an associated First Person interview with the first author of the paper.