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. 2013 Jun 10;4:1978. doi: 10.1038/ncomms2978

Figure 2. Effect of heartbeat on expression of miR-21 in the developing heart tube.

Figure 2

(a,c) Normal expression of miR-21 at the OFT (green arrowhead) and the AV canal (red arrowheads) at 48 (a) and 72 hpf (c). Dotted lines outline the heart. (b,d). In the tnnt2 morphants, expression of miR-21 was detected neither at 48 (b) nor at 72 hpf (d). (e–g) Twelve hours arrest of heartbeat (from 72 to 84 hpf in e, and from 60 to 72 hpf in f) obliterated the two patches of miR-21 expression, whereas just 1 h of heartbeat restored the full expression (g). (h–m) pri-miR-21-1 transcripts were expressed in the same patterns at 72 hpf (whole mount in h, and section in i). This expression was lost in the tnnt2 morphant heart (j). Expression of pri-miR-21 disappeared after 12 h cardiac arrest (from 72 to 84 hpf in k, and from 60 to 72 hpf in l) and 1 h of heartbeat restored it (red arrowhead in m). WT, wild type; MO, morphant; BDM, treated with BDM. Scale bars, 50 μm.