A B23-interacting sequence as a tool to visualize protein interactions in a cellular context

Citations Over TimeTop 14% of 2006 papers

Abstract

We report the characterization of a nucleolar localization sequence (NoLS) that targets the green fluorescent protein (GFP) into the granular component (GC) of nucleoli. This NoLS interacts in vitro specifically and directly with the major nucleolar protein B23 and more precisely with the region of B23 including the two acidic stretches. The affinity of NoLS for B23 is stronger than that of the HIV-1 Rev protein in vitro. Moreover, B23-NoLS interaction also occurs in vivo. Indeed, (1) NoLS confers on the GFP the behavior of B23 throughout the cell cycle, (2) the GFP-NoLS fusion and B23 remain colocalized after drug treatments, (3) a selective delocalization of B23 from nucleoli to nucleoplasm induces a concomitent delocalization of the GFP-NoLS fusion, and (4) the fusion of NoLS to fibrillarin makes it possible to colocalize fibrillarin and B23. Interestingly, by fusing NoLS to fibrillarin, both fibrillarin and the fibrillarin partner Nop56 are mislocalized in the GC of nucleoli. Similarly, by fusing the NoLS to MafG, part of the nuclear transcription factor NF-E2 composed of both MafG and p45 NF-E2, NF-E2 is redirected from the nucleoplasm to the nucleoli. Thus, we propose that the NoLS may be used as a tool to visualize and prove protein interactions in a cellular context.

Related Papers

• → Association between the nucleolus and the coiled body(1990)175 cited
• Altered subcellular distribution of nucleolar protein fibrillarin by actinomycin D in HEp-2 cells.(2004)
• → Light and electron microscopy of laser microirradiated nucleoli and nucleoplasm in tissue culture cells(1976)8 cited
• [The behavior of nucleolar proteins under the conditions of the reversible three-dimensional separation of the structural components of the nucleolus].(1995)
• [Ultrastructure of the ring-shaped nucleoli in the hepatocytes of chick embryos].(1979)