Isolation and characterization of a novel human gene, NIF3L1, and its mouse ortholog, Nif3l1, highly conserved from bacteria to mammals.

We report the cloning and characterization of novel human and murine genes NIF3L1 and Nif3l1 which are strongly homologous to the yeast Ngg1-interacting factor 3 homolog. Mouse Nif3l1 and human NIF3L1 encode predicted proteins of 376 amino acids and 377 amino acids, respectively. Northern blot analysis on RNA from different postnatal murine tissues showed a ubiquitous expression pattern of mouse Nif3l1 with a transcript of approximately 1.85 kb. RT-PCR analysis on prenatal mouse RNA and embryonic stem cell RNA demonstrated expression of Nif3l1 throughout embryonic development. Additionally, expression analysis on cell lines revealed strong overexpression of Nif3l1 in the spermatogonia-derived cell line GC-1 spg and in the teratocarcinoma cell line F9. The mouse gene was mapped to chromosome 1, region C. Human NIF3L1 consists of seven exons spanning 14.5 kb of genomic DNA and is located on chromosome 2q33. A fusion protein consisting of the GFP (green fluorescent protein) and the ORF of human NIF3L1 showed a localization of the predicted protein in the cytoplasm. In the N-terminal and C-terminal region, mouse Nif3l1 and human NIF3L1 are strongly homologous to proteins of other species, e.g. the recently cloned Drosophila symbol=anon-35F/36F gene with 41% amino acid identity and several proteins from yeast including the yeast Ngg1-interacting factor 3 homolog with 46% amino acid identity, the hypothetical protein YGL221c and yeast Ngg1-interacting factor 3 (Nif3) with 37% amino acid identity. Other proteins from lower organisms, e.g a conserved hypothetical protein from Ureaplasma urealyticum or a hypothetical protein SCC30.09c from Streptomyces coelicolor show approximately 25-30% amino acid identity in the two flanking regions of the protein. These similarities indicate a high degree of conservation of mouse Nif3l1 and human NIF3L1 from bacteria to mammals.