Research ReportExpression of the calcium binding proteins Necab-1,-2 and -3 in the adult mouse hippocampus and dentate gyrus

- We evaluated by in-situ hybridization the utility of NECABs as neuronal markers.
- NECABs in the hippocampus occur in nerve cells but rarely co-express GAD1 mRNA.
- NECABs virtually never co-exist with classical EF-hand calcium binding protein.
- Localization of NECABs mRNA's is preferable to immunohistochemical studies because of cross-reactions between the antisera.

The family of EF-hand calcium binding proteins is composed of more than 250 members. In search for other neuronal markers, we studied the expression pattern of Necab-1, -2 and -3 in the Ammons horn of adult mice at the gene- and protein levels using in-situ hybridization and immunohistochemistry. The genes for the three Necab's were expressed in specific, non-overlapping areas of the hippocampus. A minority of the Necab-positive interneurons were GABA-ergic, and they virtually never coexpressed one of the classical calcium binding proteins (calretinin, calbindin D-28k and parvalbumin). Necab's are promising new neuronal markers in the brain.