HGNC Approved Gene Symbol: NPM2
Cytogenetic location: 8p21.3 Genomic coordinates (GRCh38): 8:22,024,134-22,036,897 (from NCBI)
Burns et al. (2003) cloned mouse Npm2 and identified human NPM2. The deduced human protein contains 214 amino acids and shares 61% identity with mouse Npm2. NPM2 has a conserved bipartite nuclear localization signal followed by a stretch of negatively charged glutamic acid and aspartic acid residues implicated in protamine and histone binding. It also has several putative serine and threonine phosphorylation sites. Northern blot analysis of several mouse tissues detected a 1.0-kb transcript only in ovary, and in situ hybridization revealed expression limited to growing oocytes. Immunofluorescent localization detected Npm2 within the oocyte nucleus before nuclear membrane breakdown, after which Npm2 redistributed to the cytoplasm. Following fertilization, Npm2 localized to pronuclei and nuclei of early cleavage embryos through the 8-cell stage. Npm2 was barely detectable in blastocysts.
Burns et al. (2003) determined that the mouse Npm2 gene contains 9 exons and spans about 5.8 kb.
Burns et al. (2003) mapped the mouse Npm2 gene to chromosome 14.
Burns et al. (2003) found that female Npm2-null mice showed defects in preimplantation embryo development, with abnormalities in oocyte and early embryonic nuclei. Defects included the absence of coalesced nucleolar structures and the loss of heterochromatin and deacetylated histone H3 (see 602810), which normally circumscribe nucleoli in oocytes and early embryos, respectively. In male mice, sperm DNA decondensation proceeded in the absence of Npm2.
Burns, K. H., Viveiros, M. M., Ren, Y., Wang, P., DeMayo, F. J., Frail, D. E., Eppig, J. J., Matzuk, M. M. Roles of NPM2 in chromatin and nucleolar organization in oocytes and embryos. Science 300: 633-636, 2003. [PubMed: 12714744] [Full Text: https://doi.org/10.1126/science.1081813]