Identification of a Classical Bipartite Nuclear Localization Signal in the Drosophila TEA/ATTS Protein Scalloped
Figure 2
The NLS of Sd is directs an eGFP tag to the nucleus.
(A–G) Localization of the indicated eGFP reporter tagged peptides in transiently transfected in S2 cells with DAPI stained nuclei and visualized via confocal microscopy. A1–G1 are the green (eGFP) channels. A2–G2 are the blue (DAPI) channels. A3–G3 are the green and blue channels (merge). Hatched lines indicate the boundary of cells, as determined by the extent of the weak cytoplasmic signal. Percentages indicate the percent nuclear signal relative to total signal measured in the given cell. (A) eGFP. When eGFP is expressed alone, diffuse expression is seen throughout the cell, including the nucleus. (B) TEA-eGFP. A fragment of Sd stretching from amino acids 88–178 (which includes the entire TEA/NLS domain) shows almost exclusive reporter activity within the nucleus of the expressing cells. (C) NLS-eGFP. Amino acids 143–163 of Sd (which includes the NLS and two flanking amino acids on either side) drives reporter expression to the nucleus. (D) eGFPx2+HA (referred to hereafter as eGFPx2). eGFPx2 expression is excluded from the nucleus. (E) TEA-eGFPx2. A TEA-eGFPx2 fusion is primarily nuclear. (F) eGFPx2+NLS. This construct is found throughout the cell, but is enriched in the nucleus. (G) TEAΔNLS-eGFPx2. When the NLS is removed from the TEA domain, it is no longer able to direct the tag to the nucleus.