REF, an evolutionary conserved family of hnRNP-like proteins, interacts with TAP/Mex67p and participates in mRNA nuclear export.

Vertebrate TAP and its yeast ortholog Mex67p are involved in the export of messenger RNAs from the nucleus. TAP has also been implicated in the export of simian type D viral RNAs bearing the constitutive transport element (CTE). Although TAP directly interacts with CTE-bearing RNAs, the mode of interaction of TAP/Mex67p with cellular mRNAs is different from that with the CTE RNA and is likely to be mediated by protein-protein interactions. Here we show that Mex67p directly interacts with Yra1p, an essential yeast hnRNP-like protein. This interaction is evolutionarily conserved as Yra1p also interacts with TAP. Conditional expression in yeast cells implicates Yra1 p in the export of cellular mRNAs. Database searches revealed that Yra1p belongs to an evolutionarily conserved family of hnRNP-like proteins having more than one member in Mus musculus, Xenopus laevis, Caenorhabditis elegans, and Schizosaccharomyces pombe and at least one member in several species including plants. The murine members of the family directly interact with TAP. Because members of this protein family are characterized by the presence of one RNP-motif RNA-binding domain and exhibit RNA-binding activity, we called these proteins REF-bps for RNA and export factor binding proteins. Thus, Yra1p and members of the REF family of hnRNP-like proteins may facilitate the interaction of TAP/Mex67p with cellular mRNAs.

[1]  C. Cole,et al.  Dbp5p/Rat8p is a yeast nuclear pore‐associated DEAD‐box protein essential for RNA export , 1998, The EMBO journal.

[2]  R Grosschedl,et al.  ALY, a context-dependent coactivator of LEF-1 and AML-1, is required for TCRalpha enhancer function. , 1997, Genes & development.

[3]  U. Kutay,et al.  The C-terminal domain of TAP interacts with the nuclear pore complex and promotes export of specific CTE-bearing RNA substrates. , 2000, RNA.

[4]  J. L. Watkins,et al.  The human homologue of Saccharomyces cerevisiae Gle1p is required for poly(A)+ RNA export. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[5]  B. Séraphin,et al.  Dbp5, a DEAD‐box protein required for mRNA export, is recruited to the cytoplasmic fibrils of nuclear pore complex via a conserved interaction with CAN/Nup159p , 1999, The EMBO journal.

[6]  T. Shenk,et al.  E1B 55-Kilodalton-Associated Protein: a Cellular Protein with RNA-Binding Activity Implicated in Nucleocytoplasmic Transport of Adenovirus and Cellular mRNAs , 1998, Journal of Virology.

[7]  C. Burd,et al.  Conserved structures and diversity of functions of RNA-binding proteins. , 1994, Science.

[8]  Manolo Gouy,et al.  SEAVIEW and PHYLO_WIN: two graphic tools for sequence alignment and molecular phylogeny , 1996, Comput. Appl. Biosci..

[9]  I. Mattaj,et al.  Nucleocytoplasmic transport: the soluble phase. , 1998, Annual review of biochemistry.

[10]  Marco M. Kessler,et al.  Hrp1, a sequence-specific RNA-binding protein that shuttles between the nucleus and the cytoplasm, is required for mRNA 3'-end formation in yeast. , 1997, Genes & development.

[11]  P. Evans,et al.  The RNP domain: a sequence-specific RNA-binding domain involved in processing and transport of RNA. , 1995, Trends in biochemical sciences.

[12]  M. Wilm,et al.  TAP, the human homolog of Mex67p, mediates CTE-dependent RNA export from the nucleus. , 1998, Molecular cell.

[13]  B. Séraphin,et al.  New constructs and strategies for efficient PCR‐based gene manipulations in yeast , 1998, Yeast.

[14]  Yan Liu,et al.  Dbp5p, a cytosolic RNA helicase, is required for poly(A)+ RNA export , 1998, The EMBO journal.

[15]  J. L. Watkins,et al.  GLE2, a Saccharomyces cerevisiae homologue of the Schizosaccharomyces pombe export factor RAE1, is required for nuclear pore complex structure and function. , 1996, Molecular biology of the cell.

[16]  G. Dreyfuss,et al.  Purification and characterization of proteins of heterogeneous nuclear ribonucleoprotein complexes by affinity chromatography. , 1990, Methods in enzymology.

[17]  M. Fornerod,et al.  RAE1 Is a Shuttling mRNA Export Factor That Binds to a GLEBS-like NUP98 Motif at the Nuclear Pore Complex through Multiple Domains , 1999, The Journal of cell biology.

[18]  C. Saavedra,et al.  The simian retrovirus-1 constitutive transport element, unlike the HIV-1 RRE, uses factors required for cellular mRNA export , 1997, Current Biology.

[19]  S. Wente,et al.  An RNA-export mediator with an essential nuclear export signal , 1996, Nature.

[20]  Douglas S. Portman,et al.  RNA annealing activities in HeLa nuclei. , 1994, The EMBO journal.

[21]  R. Lührmann,et al.  Mex67p, a novel factor for nuclear mRNA export, binds to both poly(A)+ RNA and nuclear pores , 1997, The EMBO journal.

[22]  Burkhard Rost,et al.  PHD - an automatic mail server for protein secondary structure prediction , 1994, Comput. Appl. Biosci..

[23]  M. González-Escribano,et al.  Autoantibodies to transcriptional regulation proteins DEK and ALY in a patient with systemic lupus erythematosus. , 1999, Human immunology.

[24]  A. Shevchenko,et al.  Femtomole sequencing of proteins from polyacrylamide gels by nano-electrospray mass spectrometry , 1996, Nature.

[25]  S. Chen,et al.  Nuclear mRNA accumulation causes nucleolar fragmentation in yeast mtr2 mutant. , 1994, Molecular biology of the cell.

[26]  P. Philippsen,et al.  Additional modules for versatile and economical PCR‐based gene deletion and modification in Saccharomyces cerevisiae , 1998, Yeast.

[27]  E. Hudson,et al.  Identification of Novel Import and Export Signals of Human TAP, the Protein That Binds to the Constitutive Transport Element of the Type D Retrovirus mRNAs , 1999, Molecular and Cellular Biology.

[28]  G. Dreyfuss,et al.  YRA1, an essential Saccharomyces cerevisiae gene, encodes a novel nuclear protein with RNA annealing activity. , 1997, RNA.

[29]  Gapped BLAST and PSI-BLAST: A new , 1997 .

[30]  B. Séraphin,et al.  A generic protein purification method for protein complex characterization and proteome exploration , 1999, Nature Biotechnology.

[31]  J. Thompson,et al.  The CLUSTAL_X windows interface: flexible strategies for multiple sequence alignment aided by quality analysis tools. , 1997, Nucleic acids research.

[32]  G. Dreyfuss,et al.  Transport of Proteins and RNAs in and out of the Nucleus , 1999, Cell.

[33]  P. Silver,et al.  A protein that shuttles between the nucleus and the cytoplasm is an important mediator of RNA export. , 1996, Genes & development.

[34]  G. Blobel,et al.  mRNA binding protein mrnp 41 localizes to both nucleus and cytoplasm. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[35]  A. Shevchenko,et al.  Mass spectrometric sequencing of proteins silver-stained polyacrylamide gels. , 1996, Analytical chemistry.

[36]  D. Scherly,et al.  Identification of the RNA binding segment of human U1 A protein and definition of its binding site on U1 snRNA. , 1989, The EMBO journal.

[37]  R. Allshire,et al.  Fission yeast genes which disrupt mitotic chromosome segregation when overexpressed. , 1996, Nucleic acids research.

[38]  U. Kutay,et al.  Transport between the cell nucleus and the cytoplasm. , 1999, Annual review of cell and developmental biology.

[39]  B. Cullen,et al.  The human Tap protein is a nuclear mRNA export factor that contains novel RNA-binding and nucleocytoplasmic transport sequences. , 1999, Genes & development.

[40]  M. Rosbash,et al.  The yeast nucleoporin rip1p contributes to multiple export pathways with no essential role for its FG-repeat region. , 1997, Genes & development.

[41]  T J Gibson,et al.  PairWise and SearchWise: finding the optimal alignment in a simultaneous comparison of a protein profile against all DNA translation frames. , 1996, Nucleic acids research.

[42]  A. Podtelejnikov,et al.  The Mex67p‐mediated nuclear mRNA export pathway is conserved from yeast to human , 1999, The EMBO journal.

[43]  R. Wepf,et al.  A novel nuclear pore protein Nup133p with distinct roles in poly(A)+ RNA transport and nuclear pore distribution. , 1994, The EMBO journal.

[44]  M. Dasso,et al.  The human RAE1 gene is a functional homologue of Schizosaccharomyces pombe rae1 gene involved in nuclear export of Poly(A)+ RNA. , 1997, Gene.

[45]  Julie A. Brown,et al.  A Mutation in the Schizosaccharomyces pombe rae1 Gene Causes Defects in Poly(A)+ RNA Export and in the Cytoskeleton (*) , 1995, The Journal of Biological Chemistry.

[46]  A. Pasquinelli,et al.  The constitutive transport element (CTE) of Mason–Pfizer monkey virus (MPMV) accesses a cellular mRNA export pathway , 1997, The EMBO journal.

[47]  B. Fahrenkrog,et al.  The RNA export factor Gle1p is located on the cytoplasmic fibrils of the NPC and physically interacts with the FG‐nucleoporin Rip1p, the DEAD‐box protein Rat8p/Dbp5p and a new protein Ymr255p , 1999, The EMBO journal.

[48]  E. Izaurralde,et al.  TAP binds to the constitutive transport element (CTE) through a novel RNA‐binding motif that is sufficient to promote CTE‐dependent RNA export from the nucleus , 1999, The EMBO journal.

[49]  Helena Santos-Rosa,et al.  Nuclear mRNA Export Requires Complex Formation between Mex67p and Mtr2p at the Nuclear Pores , 1998, Molecular and Cellular Biology.