Fig. 4

LRRC50 missense changes are functional nulls in a zebrafish model of development.

(A) Live embryo images of lrrc50 morphants. Morpholino (MO) mediated suppression of lrrc50 gives rise to gastrulation defects in mid-somitic zebrafish embryos that can be categorized according to previously established objective scoring criteria. Representative lateral and dorsal views are shown (top and bottom panels respectively). (B) Scoring of in vivo complementation; WT embryos were injected with MO and/or human mRNA and scored at the 8–9 somite stage according to phenotypes shown in panel A. Gln307Glu and Thr590Met are not significantly different (NS; c²) from MO alone suggesting that both are functional nulls, n = 44–79 embryos/injection repeated twice with masked scoring. (C) Representative images of flat mounted in situ hybridized (ISH) zebrafish embryos labeled with a cocktail of krox20, myoD, and pax2a riboprobes. Arrows indicate measurement parameters for morphometric analyses shown in panel D; length (l) was measured as the anterior-posterior distance from the first to the last appreciable somite; width (w) was measured as the distance spanning the lateral tips of the fifth somites counted from anterior to posterior. (D) Morphometric quantification of Gln307Glu and Thr590Met gastrulation defects. Images of flat-mounted embryos age-matched at 9 somites were measured in two dimensions (as shown in panel C); the ratios of medial-lateral (width; w) versus anterior-posterior (length; l) measurements are shown for randomly chosen embryos from live scoring experiments (panels A and B) for ISH. LRRC50 Gln307Glu and Thr590Met do not produce a significant rescue in comparison to MO alone (NS; t-test), corroborating the in vivo scoring results in panel B (n = 9–13 embryos/injection). Error bars indicate standard deviation of the mean.