A study of the recombination activating gene 1 in the zebrafish nervous system

Abstract

The conserved expression of Rag1 (recombination activating gene 1) in the vertebrate nervous system indicates a neuronal function of this gene. To examine this issue, we initiated a study with the zebrafish. Using transgenesis and immunofluorescence we examined the neuronal expression of Rag1 in detail. The result shows that Rag1 is selectively expressed in subsets of neurons in many parts of the nervous system, and it is unlikely to be co-localized with Rag2. We also proved that Rag1 is not required for the axon projection of olfactory sensory neurons using morpholinos and Rag1 mutant fish. Furthermore, in a microarray experiment, we found a group of neuronal genes whose expression is altered in the Rag1 mutants. From these data, we speculate that Rag1 is likely to be involved in neuronal function via a mechanism distinct from V(D)J recombination.