Adult murine neurons: their chromatin and chromosome changes and failure to support embryonic development as revealed by nuclear transfer

Fully differentiated neurons in adult mammalian brains do not divide; consequently, their metaphase chromosomes have never been examined. Here we report metaphase chromosome constitutions of cortical neurons in adult mice visualized by a nuclear transfer technique. We found that although some reconstructed oocytes cloned from neuronal nuclei have an apparently normal karyotype, the majority do not. Regardless of chromosome morphology, nuclei of adult neurons totally lack the ability to support embryonic development. These findings support the hypothesis that fully differentiated neurons in adult mammalian brains are genomically altered.