Disease relevance of rag2

• Here we describe the induction of clonally derived T cell acute lymphoblastic leukemia in transgenic zebrafish expressing mouse c-myc under control of the zebrafish Rag2 promoter [1].

High impact information on rag2

• To follow development of the immune system in zebrafish, we have analyzed the expression of the recombination activating genes, rag1 and rag2, which we have previously isolated and characterized [2].
• It has been hypothesized that OR gene regulation may involve stochastic DNA rearrangement, which in lymphocytes requires the recombination activating genes, rag1 and rag2 [3].
• From 1 wpf, rag-1/rag-2 was expressed in kidney (together with immunoglobulin heavy chain expression) but not in spleen, while WCI12+ cells appeared 1 week later in both organs, suggesting B cell recombination in kidney but not in spleen [4].
• Rag-1/rag-2 expression was detected in thymi of animals over 1-year-old, but in kidney only at low levels, indicating life-long new formation of putative T cells but severely reduced formation of B cells in older fish [4].
• Rag-1 expression exceeded rag-2 levels in thymus and in head- and trunk-kidney of juveniles, but this ratio was reversed in head- and trunk-kidney from approximately 16 wpf onwards [4].

Biological context of rag2

• Expression of both rag1 and rag2 begins late in embryonic development, on day 4, by northern RNA blot analysis [5].
• We cloned the rag locus of the zebrafish Danio rerio and sequenced the open reading frames of the rag1 and rag2 genes [5].
• The expression of rag1 and rag2 in OSNs adds to the list of similarities between the olfactory and immune systems that includes monoallelic and mutually exclusive gene expression [3].

References