Expression of Na+/Ca2+ exchanger (NCX1) gene in the developmental mouse embryo and adult mouse brain

The Na+/Ca2+ exchanger gene, NCX1, is widely expressed in many tissues, enc oding several isoforms through alternative RNA splicing. NCX1 deficient mic e are known to be lethal at embryonic day 9-10 (E9-10). However, its expres sion pattern during embryogenesis is largely unknown. Therefore, to identif y and compare the localization and alternatively spliced isoforms of NCX1 m RNA expressed in the developmental stages, wc analyzed the mouse embryo. No rthern blot analysis demonstrated that NCX1 mRNA was expressed from the ear liest stage examined, E7. In situ hybridization analysis revealed that NCX1 mRNA was expressed in the heart alone until E10.5. However, at E14.5 and 1 6.5, NCX1 mRNA was expressed not only in the heart, but also in neuronal ce lls. In addition, the expression of NCX1 mRNA in the adult brain was most a bundant in the hippocampus. Using reverse transcription-polymerase chain re action (RT-PCR), we also identified the alternatively spliced isoforms expr essed during each developmental stage. The restricted expression of the NCX 1 gene suggested that NCX1 may play an important role in the developing mou se embryo. (C) 2001 Elsevier Science Inc. All rights reserved.