Paf1 is necessary for maintenance of blood and germline stem cell populations. (A-D) Expression of myb (A,B) or tal1 (C,D), markers of early blood precursors in the anterior and posterior lateral mesoderm at 12 hpf, is similar in alnz24 mutant and wild-type sibling embryos. (E-H) In contrast, by 26 hpf, expression of myb (E,F) and tal1 (G,H) in the intermediate cell mass is significantly reduced in alnz24 mutant embryos. (I-N) Wild-type sibling and alnz24; askopos::GFP transgenic embryos that express GFP in PGCs. Small clusters of PGCs arise similarly in wild-type and alnz24 mutant 50-60% epiboly embryos (I,J). PGCs are present in two bilateral clusters at 12 hpf (K) and coalesce at the midline above the yolk extension in 32 hpf (M) wild-type sibling embryos. In contrast, PGCs are present in ectopic locations in 12 hpf (L) and 32 hpf (N) alnz24 mutant embryos. Brackets and arrows indicate normal clusters of PGCs, whereas arrowheads indicate ectopic PGCs. y, yolk; ye, yolk extension. A-D,K,L are dorsal views with anterior towards the left; E-H,M,N, are lateral views with anterior towards the left; I,J are dorsolateral views with animal pole upwards.
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