Fig. 5

Histone H3 lysine 9 acetylation (H3K9Ac), an active transcription mark, is reduced in kat2a^−/− and kat2b^−/− zebrafish. (A–C″) Maximum projection confocal micrographs of 48 hpf zebrafish embryos labeled to detect H3K9Ac immunofluorescence (A″–C″, magenta in A–C) and neural crest cells expressing transgenic sox10:GFP (A′–C′, green in A–C). Lateral views with the anterior to the left; e, eye; ba, branchial arches. kat2a^−/− and kat2b^−/− zebrafish mutants show an overall disorganization of neural crest cells in the branchial arches as well as a reduction of H3K9Ac. (B,C) as compared to control (A). Western blots and quantification for H3K9Ac in kat2a^−/− (D,E) and kat2b^−/− (F,G) using 48 hpf zebrafish whole embryos relative to total histone H3 expression; * denotes statistical significance (p < 0.05) using Welch’s t-Test. The error bars show the standard error of the mean. (H–K) Immunofluorescence with the H3K9ac antibody and a DAPI counterstain on mouse E12.5 Kat2a^Wthat control (H,J) and Kat2a^hat/hat mouse mutant (I,K) cryosections through the frontonasal prominence, with merged images of H3K9ac and DAPI (J,K). (L) Quantification of corrected total fluorescence cell intensity (CTCF). Total fluorescence was corrected for background and area; Measurements were made using ImageJ, n = 2. Kat2a^Wt/hat is Ctrl on graphs, Kat2a^hat/hat is MUT on graphs. No significance was found for the mouse data. The scale bars represent 30 μm for zebrafish and 100 μm for mice.