Complex regulation and nuclear localization of JRK protein.
The mouse jerky gene and its human orthologue, JRK/JH8, encode a putative DNA-binding protein with homology to the CENP-B (centromere-binding protein B). Disruption of the mouse jerky gene by transgene insertion causes generalized recurrent seizures reminiscent of human idiopathic generalized epilepsy. In addition (and similar to a cenp-b null mouse) jerky null mice exhibit postnatal weight loss and reduced fertility. Using fluorescence confocal microscopy, the cellular localization of a JRK-GFP fusion (where GFP stands for green fluorescent protein) was investigated in HeLa cells. JRK-GFP has a dynamic expression pattern in the interphase nucleus, localizing in a small number of punctate nuclear foci and in the nucleolus. The JRK-GFP foci number changes during the cell cycle, but a distinct pattern of three JRK-GFP foci is observed at G(2). The endogenous protein behaves in a similar manner to the GFP-fusion protein. JRK-GFP was found to co-localize with CREST antigens (which recognize the centromere-binding proteins, CENP-A, -B and -C) through S and G(2) phases of interphase and co-localized completely with a subset of PML nuclear bodies at G(2). We speculate that JRK protein associates with a specific chromosomal centromeric locus in G(2), where it associates fully with PML bodies. Research is underway to identify this locus.
Waldron
R
R
Department of Biochemistry, Biosciences Institute, University College Cork, Ireland.
Moore
T
T
D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism* / Q000648:ultrastructure; D002503:Centromere / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D016195:G2 Phase; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins / Q000378:metabolism
D004268:DNA-Binding Proteins; D009419:Nerve Tissue Proteins; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; C095835:jrk protein, mouse; D049452:Green Fluorescent Proteins