Isolation of a murine homologue of the Drosophila neuralized gene, a gene required for axonemal integrity in spermatozoa and terminal maturation of the mammary gland

The Drosophila neuralized gene shows genetic interactions with Notch, Enhan cer of split, and other neurogenic genes and is thought to be involved in c ell fate specification in the central nervous system and the mesoderm. In a ddition, a human homologue of the Drosophila neuralized gene has been descr ibed as a potential tumor suppressor gene in malignant astrocytomas. We hav e isolated a murine homologue of the Drosophila and human Neuralized genes and, in an effort to understand its physiological function, derived mice wi th a targeted deletion of this gene. Surprisingly, mice homozygous for the introduced mutation do not show aberrant cell fate specifications in the ce ntral nervous system or in the developing mesoderm. This is in contrast to mice with targeted deletions in other vertebrate homologues of neurogenic g enes such as Notch, Delta, and Cbf-1. Male Neuralized null mice, however, a re sterile due to a defect in axoneme organization in the spermatozoa that leads to highly compromised tail movement and sperm immotility. In addition , female Neuralized null animals are defective in the final stages of mamma ry gland maturation during pregnancy.