Npp106p, a Schizosaccharomyces pombe nucleoporin similar to Saccharomyces cerevisiae Nic96p, functionally interacts with Rae1p in mRNA export.
To identify components of the mRNA export machinery in Schizosaccharomyces pombe, a screen was developed to identify mutations that were synthetically lethal with the conditional mRNA export allele rae1-167. Mutations defining three complementation groups were isolated, and here we report the characterization of npp106 (for nuclear pore protein of 106 kDa). This gene encodes a predicted protein that has significant similarity to the Nic96p nucleoporin of Saccharomyces cerevisiae. Consistent with Npp106p being a nucleoporin, a functional green fluorescent protein (GFP)-tagged Npp106p localized to the nuclear periphery. In contrast to NIC96, the npp106 gene is not essential. Moreover, a delta npp106 mutant did not show cytoplasmic mislocalization of a simian virus 40 nuclear localization signal-GFP-LacZ reporter protein, and a fraction of cells had accumulation of poly(A)+ RNA in the nucleus. A consequence of the synthetic lethality between rae1-167 and npp106-1 was the accumulation of poly(A)+ RNA in the nucleus when cells were grown under synthetic lethal conditions. In addition to npp106-1, which is a nonsense mutation that truncates the protein at amino acid 292, the delta npp106 mutation was synthetically lethal with rae1-167, suggesting that the synthetic lethality is a consequence of the loss of a function of npp106. We further demonstrate that a region between amino acids 74 and 348 of Npp106p is required for complementation of the synthetic lethality. These results uncover a potential direct or indirect involvement of Npp106p in mRNA export.
Yoon
J H
JH
Laboratory of Basic Sciences, National Cancer Institute, Bethesda, Maryland 20892, USA.
Whalen
W A
WA
Bharathi
A
A
Shen
R
R
Dhar
R
R
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001693:Biological Transport, Active; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005800:Genes, Fungal; D005804:Genes, Lethal; D005816:Genetic Complementation Test; D006801:Humans; D008565:Membrane Proteins; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D009154:Mutation; D009685:Nuclear Envelope / Q000378:metabolism; D034521:Nuclear Matrix-Associated Proteins; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D029543:Nucleocytoplasmic Transport Proteins; D016133:Polymerase Chain Reaction; D012331:RNA, Fungal / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D029702:Schizosaccharomyces pombe Proteins; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
D017931:DNA Primers; D005656:Fungal Proteins; C490524:GLE2 protein, S cerevisiae; D008565:Membrane Proteins; C082533:NIC96 protein, S cerevisiae; D034521:Nuclear Matrix-Associated Proteins; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins; D029543:Nucleocytoplasmic Transport Proteins; C490522:RAE1 protein, human; D012331:RNA, Fungal; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; C092953:rae1 protein, S pombe