<i>nol9</i>^{<i>sa1022/sa1022</i>} mutants show a decrease in the number of lymphocytes and HSPCs.

<p>A) Whole-mount <i>in situ</i> hybridization with lymphocyte-specific <i>rag1</i> probe (arrowhead) revealed that <i>nol9</i>^{<i>sa1022/sa1022</i>} larvae displayed weak to medium <i>rag1</i> expression at 96 hpf, compared to medium to strong signal in <i>nol9</i>^<i>+/+</i> or <i>nol9</i>^{<i>+/sa1022</i>} siblings. Larvae are oriented anterior to the top and ventral up. (B) The number of larvae displaying different degrees of <i>rag1</i> expression as assessed by WISH. Data are represented as the number of larvae belonging to each phenotypic group. Fisher’s exact test, ** p<0.01. (C) Whole-mount <i>in situ</i> hybridization against the thymic epithelium marker <i>foxn1</i> at 96 hpf revealed a similar level of signal (arrow) in <i>nol9</i>^<i>+/+</i> and <i>nol9</i>^{<i>sa1022/sa1022</i>} siblings. (D) Whole-mount <i>in situ</i> hybridization using a <i>c-myb</i> riboprobe was used to assess the number of HSCs emerging in the AGM region at 36 hpf (arrow) and the number of HSPCs in the CHT (arrow) at 72 hpf. Representative pictures of the AGM region (36 hpf) and the CHT (72 hpf) are shown. Mutant <i>nol9</i>^{<i>sa1022/sa1022</i>} embryos displayed normal <i>c-myb</i> signal at 36 hpf and decreased <i>c-myb</i> signal at 72 hpf compared to wt siblings. Fisher’s exact test, **, p<0.01. All embryos are oriented with anterior to the left and dorsal to the top. Numbers represent embryos with the displayed phenotype out of the total number of embryos examined.