Plk1 & Myocardial Regeneration Figure 3. Expression of Plk2, Plk3 and Plk4 protein levels are regulated during cardiac myocyte development. Ventricular cardiac myocytes were isolated from hearts at various stages of development (embryonic day 18 [E18], 2, 5 and 10 days postnatal [P2, P5 and P10] and adult [250 g males]) and assessed for Plk2, Plk3 and Plk4 protein expression (A, C and E, respectively, black bars). Samples were normalised to GAPDH. Each bar chart represents data from at least 3 separate experiments, * p,0.05. Representative blots are shown for Plk2 (B), Plk3 ((D) and Plk4 (F). doi:10.1371/journal.pone.0006752.g003 PLoS ONE | www.plosone.org 6 August 2009 | Volume 4 | Issue 8 | e6752