Hi. If you are planning to use primary cells, it is better to establish your own stable cell lines. I have 2 recommendations. 1) Choose actin-GFP, not GFP-actin because attaching GFP before actin seems to affect cell's behavior (https://www.jstage.jst.go.jp/article/csf/42/2/42_17016/_html/-char/en)

2) If you are trying to establish a stable cell line, try lentiviruses (better pre-packaged and ready-to-use, such as from here https://www.systembio.com/products/imaging-and-reporter-vectors/cyto-tracers/pct-actin-gfp-cmv/), or go with transposable elements (piggyBac plasmids).

Hi Yulia, thank you for your advice. I am considering the systemsbio lentiviral vector or the LifeAct one from Ibidi. Do you have any advice based on good results you have gotten in terms of efficacy for dosing lentivirus for easy to transduce (ex. HEK293T) vs. primary?

LifeAct is the way to go. In fact, I have friends who use LifeAct transgenic mice because of how similar to real actin it behaves. Full fusion proteins to actin are prone to behavioral artifacts because of steric hindrance.

Thank you for the recommendation, Jordan!

There is a very nice comparison of various Actin tools for live cell imaging:

Actin visualization at a glance. Melak et al. 2017

Article Actin visualization at a glance

I hope this helps :-)