Locating the nuclear localization signal in S. cerevisiae ribosomal protein L15A

• Newly synthesized ribosomal proteins (r-proteins) are efficiently transported from the cytoplasm to the site of ribosome assembly in the nucleolus. Nuclear import is facilitated by the presence of a nuclear localization signal (NLS) whereas the nucleolar accumulation requires a nucleolar localization signal (NoLS). In this study we located the NLS of the essential r-protein YrpL15A by studying the ability of various YrpL15A-gfp constructs to enter the nucleus and nucleolus. We found that the NLS signal is located in the C-terminal part of the protein. The identified sequence was sufficient to direct the reporter construct to the nucleus in yeast cells. This protein fragment contains a sequence that resembles a classical monopartite NLS. The fragment also contains a NoLS as seen by the partial co-localization of reporter construct with the nucleolar marker protein nop1. Orthologs of YrpL15A such as rpL15B from Arabidopsis thaliana and rpL15A from Schizosaccharomyces pombe were also able to enter the nucleus and nucleolus of yeast cells, suggesting that their NLS and NoLS are similar to that found in YrpL15. These results are discussed in relation to sequence similarities/dissimilarities. YrpL15A containing a C-terminal tag was unable to assemble into large ribosomal subunits that were transported to the cytoplasm.

Ämnesord

NATURVETENSKAP  -- Biologi -- Biokemi och molekylärbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biochemistry and Molecular Biology (hsv//eng)

Nyckelord

Ribosomal protein L15

Functional complementation

Nuclear localization

Yeast

Publikations- och innehållstyp

vet (ämneskategori)

ovr (ämneskategori)