Effect of SCID-derived JAK3 mutations on zebrafish larval lymphopoiesis. Analysis of immune and blood cells in 28 dpf wild-type (wt/wt) and mutant (mdu9/mdu9) jak3 larvae using RT-PCR with primers specific for T cell receptor (TCR) β-chain (v(d)j-cβ vb1.5, vb12, vb14.5) and B cell Ig heavy chain (igvh1, igvh4) rearrangements along with actb as a control (n = 2) (A), noting that RT-negative controls yielded no products, or qRT2-PCR analysis with the indicated hematopoietic cell markers (B). Data is represented as relative fold-change compared to homozygous wild-type (wt/wt) larvae with mean and SEM shown in red and level of statistical significance of normalized Cq values (relative to control actb) indicated (** p < 0.01, * p < 0.05, ns not significant; n = 3).