Two novel mouse genes-Nubp2, mapped to the t-complex on chromosome 17, andNubp1, mapped to chromosome 16 - Establish a new gene family of nucleotide-binding proteins in eukaryotes

Two novel mouse genes and one novel human gene that define distinctive euka ryotic nucleotide-binding proteins (NUBP) and are related to the mrp gene o f prokaryotes are characterized. Phylogenetic analyses of the genes, encodi ng a short form (Nubp2) and a long form (Nubp1) of NUBP, clearly establish them as a new NUBP/MRP gene family that is well conserved throughout phylog eny. In addition to conserved ATP/GTP-binding motifs A (P-loop) and A', mem bers of this family share at least two highly conserved sequence motifs, NU BP/MRP motifs alpha and beta. Only one type of NUBP/MRP gene has been obser ved thus far in prokaryotes, but there are two types in eukaryotes. One gro up includes mouse Nubp1, human NBP, yeast NBP35, and Caenorhabditis elegans F10G8.6 and is characterized by a unique N-terminal sequence with four cys teine residues that is lacking in the other group, which includes mouse Nub p2, human NUBP2, and yeast YIA3w. Northern blot analyses of the two mouse g enes show distinctive patterns consistent with this classification. Mouse N ubp2 is mapped to the t-complex region of mouse Chromosome 17, whereas Nubp 1 is mapped to the proximal region of mouse Chromosome 16. Interestingly, b oth regions are syntenic with human chromosome 16p13.1-p13.3, suggesting th at a chromosomal breakage between Nubp2 and Nubp1 probably occurred during the evolution of mouse chromosomes. (C) 1999 Academic Press.