G9a morphants largely phenocopy dnmt3 morphants. A, splice blocking by g9a splice-blocking morpholino (g9a Mo1) was monitored by RT-PCR in mRNAs made from control and g9a morphants at 80 hpf using a forward primer in the exon and reverse primer in the next exon. Note that the g9a morpholino stabilizes the unspliced transcript containing the intermediate intron, whereas the spliced version is detected in control-injected embryos. The percent knockdown shown is the ratio of intensity of unspliced product to combined intensity of unspliced and spliced products normalized to intensity of the β-actin band. Note that a product can be amplified with an intronic primer in the g9a morphants; however, this was not taken into account while calculating percent knockdown. B, morphology defects in g9a morphants at 80 hpf. Note the smaller head in g9a morphants, as with dnmt3 morphants. Bar equals 0.5 mm. C, whole mount in situ analysis of ascl1b, crx, neurod, fabp2, and irbp expression in g9a, suv39h1, and control morphants. ascl1b was analyzed at 30 hpf, whereas all others were analyzed at 80 hpf. The defects present in g9a morphants were complemented by co-injection of the wild-type G9a (G9aWT), but not by the catalytically inactive derivative G9aC1133A. D, expression of exogenous G9a constructs. HEK293 cells were transfected with the wild-type or catalytically dead derivatives of GFP-tagged zebrafish G9a (G9aWT and G9aC1133A). Westerns using antibodies against the GFP tag show equal expression of these derivatives. β-Actin was used a loading control.
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