Fig. 5.

Nol9 n-pNoLS is responsible for Nol9 nucleolar localization. (a) Bioinformatic analysis⁴⁸ of the Nol9 primary sequence identified the putative N-terminal nucleolar localization sequence (n-pNoLS) and the putative C-terminal nucleolar localization sequence (c-pNoLS). Red boxes highlight arginine and lysine residues characteristic of NoLS signals. Gray profiles above each sequence alignment displays the predicted relative surface accessibility (RSA) generated by NetSurfP-2.0⁶⁷. Positive RSA values mark residues with a high probability of being surface exposed and negative RSA values identify residues that are likely buried. Abbreviations are as follows: Hs (Homo sapiens), Bt (Bos taurus), Mm (Mus musculus), Dr (Danio rerio), Xl (Xenopus laevis), Dm (Drosophila melanogaster), Ad (Anopheles darlingi), Sm (Stegodyphus mimosarum). (b) Domain architecture of human Nol9 variants colored as seen in panel 2a. The magenta box represents the putative N-terminal nucleolar localization sequence (n-pNoLS) and the dark beige box represents the putative C-terminal nucleolar localization sequence (c-pNoLS). (c) Representative high-resolution images of transiently expressed GFP-Nol9, GFP-Nol9 Δn-pNoLS and GFP-Nol9 Δc-pNoLS in fixed U2OS cells. (d) Representative high-resolution images of transiently expressed GFP reporter, GFP reporter fused to n-pNoLS and GFP reporter fused to c-pNoLS. 4′,6-diamidino-2-phenylindole (DAPI, blue) was used to visualize the nucleus. Scale bars, 6 μm.