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. 2004 May 27;23(12):2440–2450. doi: 10.1038/sj.emboj.7600258

Figure 6.

Figure 6

Pros maintains LG precursors proliferative by controlling G1 arrest. LG-lacZ visualised with anti-βgal (A–G) in red; (H–L) in blue. (A) Anti-Notch (green) in wild type (stage 14), single-channel and merged images. (B) Anti-Notch (green) undetectable in pros mutant embryos. (C) Expression of activated Notch in the LG causes upregulation of Pros in all LG (anti-Pros, green) (htlGAL4; F263/UASNotchintra). (D) Expression of numb in the LG causes downregulation of Pros in all LG except for the most anterior two (arrowheads, anti-Pros, green) (htlGAL4;F263/UASnumb). (E) Anti-CycE (green) in one LG (stage 14). (F) Anti-CycA (green) in one LG (stage 14). (G) No anti-CycB (green) in the LG at stage 15. Single-channel views of (E, F, G) show only the cyclins. (H–M) Induction of BrdU incorporation (anti-BrdU, brown, arrowheads) at stage 14 in the LG (blue) upon the expression of cycE in LG in: (H) control (F263): no BrdU incorporation; (I) control expressing cycE in LG (htlG4; F263/UAScycE); (J) embryo expressing in LG cycE and Notch-intra (htlG4;F263/UAScycE UASNotch-intra), 1.5 hemisegments shown; (K) embryo expressing in LG numb and cycE (htlG4;F263/UAScycE UASnumb). (L) pros mutant expressing cycE in LG (htlG4; F263 pros-/UAScycE pros-). (M) Quantification of BrdU incorporation. Compared to the UAScycE control, there is an increase in the frequency of hemisegments with (1) no BrdU in pros mutants (planned comparison, P<0.0005), (2) BrdU in only 1–2 LG when expressing UASNumb (planned comparison, P<0.005), (3) BrdU in >7 LG when expressing UASNotch-intra. There is a decrease in the frequency of hemisegments with BrdU in 3–6 LG when expressing UASNumb (planned comparison, P<0.0005). (N) Summarising diagram, showing in wild type the six LG in G1 arrest (blue) and the remaining LG in G0, and the incorporation of BrdU (orange, i.e. cells in S phase, S) in the experiments shown in the photos immediately above. In (A–G), blue is TOTO-3.All images show one hemisegment, midline to the left, anterior up; n=number of hemisegments.