Skip to main content
. 2019 Sep 10;37(1):124–133. doi: 10.1093/molbev/msz207

Fig. 4.

Fig. 4.

Archaeal NLS-type motifs can functionally substitute NLS-signals of the eukaryotic ribosomal protein uS12 in human cells. (A) Western blot of HEK293T cells extracts to evaluate expression of uS12-eGFP fusions: the labels correspond to eGFP and uS12-eGFP fusions where H.s. stands for Human sapiens, S.s.—Sulfolobus solfataricus, and T.a.—Thermoplasma acidophilum. (B–K) The panels show microscopic snapshots of eGFP fluorescence (green, top panels) and fluorescence of the DNA-staining agent DAPI (blue, bottom panels) in the human cell line HEK293T. Red arrows point to the location of human cell nucleoli. Cells are expressing the following eGFP fusions: (B, C) eGFP alone (as a negative control) shows both cytoplasmic and nuclear localization; (D, E) eGFP fusion with human uS12 accumulates in nucleoli; (F, G) eGFP fusion with human uS12 lacking the NLS-containing N-terminus (residues 1–41) is no longer localized in cell nucleoli; (H, I) eGFP fusion with human uS12 in which the N-terminus (residues 1–41) is replaced by the N-terminus of uS12 from the archaeon S. solfataricus; (J, K) eGFP fusion with human uS12 in which the N-terminus (residues 1–41) is replaced by the N-terminus of uS12 from the archaeon T. acidophilum. The panels H–K illustrate that N-terminal segments of the archaeal ribosomal protein uS12 (either from S. solfataricus or T. acidophilum) are able to functionally substitute the NLS-containing N-terminal segment of human uS12, to direct uS12 accumulation in human cell nucleoli.