Cloning, expression and nuclear localization of human NPM3, a member of the nucleophosmin/nucleoplasmin family of nuclear chaperones.

摘要: Studies suggest that the related proteins nucleoplasmin and nucleophosmin (also called B23, NO38 or numatrin) are nuclear chaperones mediate assembly of nucleosomes ribosomes, respectively, these activities accomplished through binding basic via their acidic domains. Recently discovered less well characterized members this family phosphoproteins include mouse nucleophosmin/nucleoplasmin 3 (Npm3) Xenopus NO29. Here we report cloning initial characterization human ortholog Npm3. Human genomic cDNA clones NPM3 were isolated sequenced. lies 5.5 kb upstream FGF8 thus maps to chromosome 10q24-26. In addition amino acid similarities, shares many physical characteristics with family, including an domain, multiple potential phosphorylation sites a putative localization signal. Comparative analyses 14 from various metazoans NO29 is candidate NPM3, they further group both closer nucleoplasmins than nucleophosmins. Northern blot analysis revealed was strongly expressed in all 16 tissues examined, especially robust expression pancreas testis; lung displayed lowest level expression. An subcellular fractions NIH3T3 cells expressing epitope-tagged protein localized solely nucleus. abundant widely primarily localization. These biological activities, together its relationship chaparones nucleophosmin, consistent proposed function as molecular chaperone functioning