Fig 1. Normal Brg1 protein levels are essential for blastula gene expression and survival.

(A) Target sites of antisense Morpholinos on Xenopus Brg1 mRNAs. Start codon in capital letters; sequence mismatches between Xenopus species are labeled in red. (B) Radial injections of BMO1 (30ng/embryo) and BMO2 (60ng/embryo) in X. tropicalis embryos cause embryonic death from gastrulation stages on (n = 8 biological experiments), while CoMO (60ng/embryo) injected embryos survived beyond hatching stage. Please note that the majority of BMO2 injected embryos die during neurulation. The death counts were recorded at the indicated color-coded stages. NF9: late blastula; NF15: neural fold stage; NF22: late neurula; NF36: hatching. (C) Western Blot analysis of unmanipulated or radially injected X. tropicalis embryos at late blastula stage (NF9). Brg1 protein levels were quantified relative to α-tubulin and normalized to CoMO-injections. BMO1 injected embryos had a mean Brg1 protein level of 0.48, while BMO2 injected embryos had a mean Brg1 protein level of 0.6 (n = 8 experiments). (D) Pie-diagram of the microarray analysis comparing CoMO and BMO1 morphant X. tropicalis at NF9 (averaged from four independent experiments). At this stage, 10216 mRNAs classified the active gene pool; 91.4% of these were unaffected, 6.5% were down- and 2.1% were upregulated by Brg1 protein knockdown (lfdr > 0.2). (E) Validation of the responders from the GO-term “nervous system development” by qRT/PCR (n = 8 independent experiments). Asterisks mark genes, which were significantly downregulated in the qRT/PCR analysis (p-value < 0.05).