The Expression Of RAG-1 In Brain During Mouse Development

The development of central nervous system is a complicated and precise procedure. All kinds of genes express temporally under the control of unknowing mechanism, their products also control the migration,proliferation,differentiation, growth and extinction of nerve cells. The development of cerebral cortex cells is according to the rule from interior to exterior, which layer was localized in cerebral cortex, was controlled by endogenic and ectogenic signals, but the endogenic signals are in the most.The compound of RAG-1 and RAG-2 can identify specifically recombination signal sequence which lie two sides of the V, DH,J gene segment in Ig germline gene, then break DNA and induce the recombination of V(D)J gene segment. RAGs are the basis of antibody diversity during the lymphocyte development. Central nervous system maybe exist the site specific recombination.The changes of expression level of recombination activating gene 1 (RAG-1) during brain developmental were investigated and tissue localizated by RT-PCR and immunohistochemistry. Then we try to find the RAG-l's action during the development of central nervous system and offer theory basis for next research.[Methods]The brain tissues of embryonic day (E)11,E13,E15,E17,E19, new-born and adult mice were taken out, the total RNA were extracted and the changes of RAG-1 expression were investigated with the method of RT-PCR. The primer: RAG-1 wide type: sense: 5' ACTCAATTCTGACTCAACG 3' Antisense: 5' AACAGATGTCACAGGACG 3'. Afterwards, each group brain tissues were fixated by formaldehydum polymerisatum, the frozen coronalsections of each group brain tissues were stained with immunohistochemistry method and Nissl's staining, to localize the expression of RAG-1. the results of immunohistochemistry were statistical analysised.[Results]We observed the expression of RAG-1 in Ell localized ventricular zone (VZ);the expression of RAG-1 in El3 localize VZ> IZ> nucleus amygdalae and hypothalamus, the RAG-1 positive neurons are mostly immature and few apophysis;the expression of RAG-1 in El5 is decrease in VZ, RAG-1 mostly expresses in corticle plate (CP) , there are many positive nerve fibers in nucleus amygdalae > hypothalamus and thalamus;with the development of the cerebral cortex, the RAG-1 positive neurons and nerve fibers also express subventricular zone (SVZ) and CP in E17;the expression of RAG-1 in E19 is the same to that in El7, but the expression is decrease in VZ and SVZ and increase in CP and subcorticle plate(SP);the expression of RAG-1 localize mostly in CP and Hippocampus in new-born mouse, the form of RAG-1 positive neurons is the same to that in adult mouse;RAG-1 express hippocampus, granular cell in cerebellum, several in the cortex of frontal lobe and temporal lobe in adult mouse.The result showed that the expression is increase from Ell to El9 and decrease in the new-born mouse brain, but the expression level is also higher than that in the adult mouse. The result of RT-PCR is coincided with the result of immunohistchemisty, but the expression peak occured in El 7.I Conclusion!RAG-1 express in mouse embryonic brain tissue and the expression is related with the neuron development;the expression level of RAG-1 in embryonic brain tissue is higher than that in the adult mouse.