ActA expression was similar following infection with WT L. monocytogenes, an actA deletion strain (LmΔactA::pPL1-actA strain), or an Lm-RIID strain complemented at the comK locus (Lm-RIID::pPL1-actA strain) (Fig. 2a, lanes 3 to 5), and ActA+ strains formed actin tails in host cells (Fig. 2b). This evidence concerns the gene ACTA1 and infection.