Morpholino mediated knockdown of zebrafish kindlin-2 results in abnormal developmental angiogenesis. (A) Control morphant (CTL MO) embryo examined by live microscopy at 48 hpf. Proper vessel formation was observed in all control morphant embryos. ISV indicates intersegmental vessel; DLAV, longitudinal anastamotic vessel; DA, dorsal aorta; and PCV, posterior cardinal vein. (B-C) Two examples of kindlin-2 morphants (KIND2 MO). DLAVs were discontinuous and absent in many places (**). ISVs were thin and short. Aberrant horizontal interconnecting vessels were also frequently observed (arrows). Scale bar, 50 μm. (D) Quantitation of total ISV length. ISVs were measured at 48 hpf in control and kindlin-2 morphants. Average values (in micrometers) were (CTL vs KIND2): 114 ± 14 versus 71 ± 10; P = .02. Four independent experiments were performed with 10 fish per group.