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. Author manuscript; available in PMC: 2013 Apr 11.
Published in final edited form as: Nat Commun. 2011 Jul 12;2:390. doi: 10.1038/ncomms1381

Figure 4. Segmentation clock gene expression in Msgn1−/− mutants.

Figure 4

WISH analysis of Sp5 (a-f), Sprouty2 (g-l), Dll1 (m,n), Dll3 (s,t), Notch1 (y,z), Hes7 (a’,b’), Lfng (c’,d’), Nrarp (e’,f’,o-r), and Maml3 (u-x) expression in wildtype (a,c,d,g,i,j,m,o,p,s,u,v,y,a’,c’,e’) or Msgn1−/− (b,e,f,h,k,l,n,q,r,t,w,x,z,b’,d’,f’) embryos at E8.5. The cyclic Wnt target genes Sp5 (n=4; a, b) and Axin2 (n=6, not shown) were upregulated in the Msgn1−/− PSM, while the overall expression levels of the oscillating Fgf pathway genes Sprouty2 (n=5; g, h) and Dusp6 (n=4, not shown)1, were maintained in Msgn1−/− embryos at levels similar to that observed in control embryos. In contrast, Dll1 (n=5; m,n), Dll3 (n=5; s,t), Notch1 (n=5; y,z), Hes7 (n=5; a’,b’), and Lfng (n=8; c’,d’) were significantly downregulated in the posterior PSM. Weak stripes of expression were frequently detected in the anterior PSM (arrows, c’,d’) of E8.5 mutants that were not observed at E9.520. Nrarp (n=9; e’,f’) and Maml3 (n=11; not shown) were strongly expressed in the posterior PSM. Nrarp was not expressed in stripes in Msgn1−/− embryos as it is in wildtype littermates, and expression was graded, more closely resembling Wnt target gene expression than Notch target genes (compare Fig. 4f’ with 4b and d’). (c-f,i-l,o-r,u-x) Lateral views of half-embryo explants analyzed by WISH. Using the explanted PSM “fix and culture” method, gene expression was assessed in a fixed, reference PSM explanted from one half of a wildtype or Msgn1−/− embryo (t=0), and compared to its expression in the complementary half after it had been cultured for roughly a half cycle of cyclic gene expression (60-90 minutes). The expression patterns of Sp5 (n=2; c, d) Axin2 (n=2, not shown), Sprouty2 (n=2; i, j), Nrarp (n=5, o,p), and Maml3 (n=2; u,v) differed between fixed (t=0) and cultured (t=60-90′) wildtype control explants as expected, indicative of dynamic oscillating expression, but did not change significantly between fixed (t=0) and cultured (t=60-90′) Msgn1−/− halves. Scale bar = 100 μm.