scholarly journals A mutant nuclear protein with similarity to RNA binding proteins interferes with nuclear import in yeast.

1992 ◽  
Vol 3 (8) ◽  
pp. 875-893 ◽  
Author(s):  
M A Bossie ◽  
C DeHoratius ◽  
G Barcelo ◽  
P Silver
Keyword(s):  
Nuclear Protein ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Protein Localization ◽  
T Antigen ◽  
Nuclear Proteins ◽  
Nuclear Localization Sequence ◽  
Temperature Sensitive ◽  
Rna Recognition Motif ◽  
Yeast Saccharomyces Cerevisiae

We have isolated mutants of the yeast Saccharomyces cerevisiae that are defective in localization of nuclear proteins. Chimeric proteins containing the nuclear localization sequence from SV40 large T-antigen fused to the N-terminus of the mitochondrial F1 beta-ATPase are localized to the nucleus. Npl (nuclear protein localization) mutants were isolated by their ability to grow on glycerol as a consequence of no longer exclusively targeting SV40-F1 beta-ATPase to the nucleus. All mutants with defects in localization of nucleolar proteins and histones are temperature sensitive for growth at 36 degrees C. Seven alleles of NPL3 and single alleles of several additional genes were isolated. NPL3 mutants were studied in detail. NPL3 encodes a nuclear protein with an RNA recognition motif and similarities to a family of proteins involved in RNA metabolism. Our genetic analysis indicates that NPL3 is essential for normal cell growth; cells lacking NPL3 are temperature sensitive for growth but do not exhibit a defect in localization of nuclear proteins. Taken together, these results indicate that the mutant forms of Npl3 protein isolated by this procedure are interfering with nuclear protein uptake in a general manner.

scholarly journals Analysis of conserved binding proteins for nuclear localization sequences

1993 ◽  
Vol 104 (1) ◽  
pp. 89-95 ◽  
Author(s):  
U. Stochaj ◽  
M.A. Bossie ◽  
K. van Zee ◽  
A.M. Whalen ◽  
P.A. Silver
Keyword(s):  
Nuclear Localization ◽  
Binding Proteins ◽  
Nuclear Protein ◽  
Protein Localization ◽  
T Antigen ◽  
Nuclear Proteins ◽  
Nuclear Localization Sequence ◽  
Nuclear Pore ◽  
Permissive Temperature ◽  
Nuclear Localization Sequences

Correct targeting of nuclear proteins is mediated by nuclear localization sequences (NLS) which permit specific binding to the nucleus and subsequent translocation across the nuclear envelope via the nuclear pore complex. It is proposed that nuclear import is facilitated by NLS-receptors which reside in the cytoplasm and at the nuclear pore. These NLS-receptors could facilitate an early step of nuclear protein import, i.e. targeting and binding of nuclear proteins at the nuclear pore. We have generated anti-idiotype antibodies against the SV40 T-antigen nuclear localization sequence that allowed us to study NLS-binding proteins in a variety of different organisms. Proteins of similar size are recognized by these antibodies in yeast, Drosophila, rat and human cells. Cytological analysis indicates that the NLS-binding proteins reside in part at nuclear pores. One of the proteins recognized by anti-idiotype antibodies is identical to a previously identified NLS-binding protein. Using isolated yeast nuclei we demonstrate that the anti-idiotype antibodies compete for binding of nuclear proteins in vitro. We show that the yeast mutant npl3, which is defective in nuclear protein localization, has an altered distribution of antigens recognized by these anti-idiotype antibodies, at the semi-permissive temperature. Our results suggest that a set of proteins common to various eukaryotes recognizes nuclear localization sequences.

scholarly journals A yeast RNA-binding protein shuttles between the nucleus and the cytoplasm.

1994 ◽  
Vol 14 (12) ◽  
pp. 8399-8407 ◽  
Author(s):  
J Flach ◽  
M Bossie ◽  
J Vogel ◽  
A Corbett ◽  
T Jinks ◽  
...  
Keyword(s):  
Nuclear Protein ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Rna Binding Protein ◽  
Wild Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Binding Motifs ◽  
C Terminus ◽  
N Terminus ◽  
Heterogeneous Nuclear Ribonucleoproteins

RNA-binding proteins have been suggested to move in association with RNA as it leaves the nucleus. The NPL3 gene of the yeast Saccharomyces cerevisiae encodes in nuclear protein with consensus RNA-binding motifs and similarity to heterogeneous nuclear ribonucleoproteins and members of the S/R protein family. We show that although Npl3 is located in the nucleus, it can shuttle between nuclei in yeast heterokaryons. In contrast, other nucleus-targeted proteins do not leave the nucleus under similar conditions. Mutants missing the RNA-binding motifs or the N terminus are still capable of shuttling in and out of the nucleus. Npl3 mutants missing the C terminus fail to localize to the nucleus. Overproduction of Npl3 in wild-type cells shows cell growth. This toxicity depends on the presence of series of unique repeats in the N terminus and localization to the nucleus. We suggest that the properties of Npl3 are consistent with it being involved in export of RNAs from the nucleus.

scholarly journals Potential RNA Binding Proteins in Saccharomyces cerevisiae Identified as Suppressors of Temperature-Sensitive Mutations in NPL3

Genetics ◽  
1996 ◽  
Vol 142 (1) ◽  
pp. 103-115 ◽  
Author(s):  
Michael Henry ◽  
Christina Z Borland ◽  
Mark Bossie ◽  
Pamela A Silver
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Import ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Temperature Sensitive ◽  
Yeast Saccharomyces Cerevisiae ◽  
Heterogeneous Nuclear Ribonucleoproteins ◽  
Rna Export ◽  
Complementation Groups ◽  
Export Protein

The NPL3 gene of the yeast Saccharomyces cerevisiae encodes a protein with similarity to heterogeneous nuclear ribonucleoproteins (hnRNPs). Npl3p has been implicated in many nuclear-related events including RNA export, protein import, and rRNA processing. Several temperature-sensitive alleles of NPL3 have been isolated. We now report the sequence of these alleles. For one allele, npl3-1, four complementation groups of suppressors have been isolated. The cognate genes for the two recessive mutants were cloned. One of these is the previously known RNA15, which, like NPL3, also encodes a protein with similarity to the vertebrate hnRNP A/B protein family. The other suppressor corresponds to a newly defined gene we term HRP1, which also encodes a protein with similarity to the hnRNP A/B proteins of vertebrates. Mutations in HRP1 suppress all npl3 temperature-sensitive alleles but do not bypass an npl3 null allele. We show that HRP1 is essential for cell growth and that the corresponding protein is located in the nucleus. The discovery of two hnRNP homologues that can partially suppress the function of Npl3p, also an RNA binding protein, will be discussed in terms of the possible roles for Npl3p in RNA metabolism.

scholarly journals A yeast RNA-binding protein shuttles between the nucleus and the cytoplasm

1994 ◽  
Vol 14 (12) ◽  
pp. 8399-8407
Author(s):  
J Flach ◽  
M Bossie ◽  
J Vogel ◽  
A Corbett ◽  
T Jinks ◽  
...  
Keyword(s):  
Nuclear Protein ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Rna Binding Protein ◽  
Wild Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Binding Motifs ◽  
C Terminus ◽  
N Terminus ◽  
Heterogeneous Nuclear Ribonucleoproteins

RNA-binding proteins have been suggested to move in association with RNA as it leaves the nucleus. The NPL3 gene of the yeast Saccharomyces cerevisiae encodes in nuclear protein with consensus RNA-binding motifs and similarity to heterogeneous nuclear ribonucleoproteins and members of the S/R protein family. We show that although Npl3 is located in the nucleus, it can shuttle between nuclei in yeast heterokaryons. In contrast, other nucleus-targeted proteins do not leave the nucleus under similar conditions. Mutants missing the RNA-binding motifs or the N terminus are still capable of shuttling in and out of the nucleus. Npl3 mutants missing the C terminus fail to localize to the nucleus. Overproduction of Npl3 in wild-type cells shows cell growth. This toxicity depends on the presence of series of unique repeats in the N terminus and localization to the nucleus. We suggest that the properties of Npl3 are consistent with it being involved in export of RNAs from the nucleus.

scholarly journals Extragenic suppressors of mutations in the cytoplasmic C terminus of SEC63 define five genes in Saccharomyces cerevisiae.

Genetics ◽  
1993 ◽  
Vol 134 (1) ◽  
pp. 159-173 ◽  
Author(s):  
M K Nelson ◽  
T Kurihara ◽  
P A Silver
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nuclear Protein ◽  
Protein Localization ◽  
Nuclear Localization Sequence ◽  
Temperature Sensitive ◽  
C Terminus ◽  
Nuclear Antigens ◽  
Regional Specificity ◽  
Localization Sequence ◽  
Sensitive Allele

Abstract Mutations in the SEC63 gene of Saccharomyces cerevisiae affect both nuclear protein localization and translocation of proteins into the endoplasmic reticulum. We now report the isolation of suppressors of sec63-101 (formerly npl1-1), a temperature-sensitive allele of SEC63. Five complementation groups of extragenic mutations, son1-son5 (suppressor of npl1-1), were identified among the recessive suppressors. The son mutations are specific to SEC63, are not bypass suppressors, and are not new alleles of previously identified secretory (SEC61, SEC62, KAR2) or nuclear protein localization genes (NPL3, NPL4, NPL6). son1 mutations show regional specificity of suppression of sec63 alleles. At low temperatures, son1 mutants grow slowly and show partial mislocalization of nuclear antigens. The SON1 gene maps to chromosome IV and encodes a nuclear protein of 531 amino acids that contains two acidic stretches and a putative nuclear localization sequence. We show that son1 mutations suppress sec63-101 by elimination of Son1p function.

The Drosophila suppressor of sable gene encodes a polypeptide with regions similar to those of RNA-binding proteins

1991 ◽  
Vol 11 (2) ◽  
pp. 894-905
Author(s):  
R A Voelker ◽  
W Gibson ◽  
J P Graves ◽  
J F Sterling ◽  
M T Eisenberg
Keyword(s):  
Rna Processing ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Open Reading Frame ◽  
In Vitro Translation ◽  
Rna Recognition Motif ◽  
Reading Frame ◽  
Cdna Sequences ◽  
Suppressor Of Sable

The nucleotide sequence of the Drosophila melanogaster suppressor of sable [su(s)] gene has been determined. Comparison of genomic and cDNA sequences indicates that an approximately 7,860-nucleotide primary transcript is processed into an approximately 5-kb message, expressed during all stages of the life cycle, that contains an open reading frame capable of encoding a 1,322-amino-acid protein of approximately 150 kDa. The putative protein contains an RNA recognition motif-like region and a highly charged arginine-, lysine-, serine-, aspartic or glutamic acid-rich region that is similar to a region contained in several RNA-processing proteins. In vitro translation of in vitro-transcribed RNA from a complete cDNA yields a product whose size agrees with the size predicted by the open reading frame. Antisera against su(s) fusion proteins recognize the in vitro-translated protein and detect a protein of identical size in the nuclear fractions from tissue culture cells and embryos. The protein is also present in smaller amounts in cytoplasmic fractions of embryos. That the su(s) protein has regions similar in structure to RNA-processing protein is consistent with its known role in affecting the transcript levels of those alleles that it suppresses.

scholarly journals Structural basis for recognition of human 7SK long noncoding RNA by the La-related protein Larp7

2018 ◽  
Vol 115 (28) ◽  
pp. E6457-E6466 ◽  
Author(s):  
Catherine D. Eichhorn ◽  
Yuan Yang ◽  
Lucas Repeta ◽  
Juli Feigon
Keyword(s):  
Noncoding Rna ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Transcription Elongation ◽  
Structural Basis ◽  
Titration Calorimetry ◽  
Rna Recognition Motif ◽  
Related Protein ◽  
Binding Interface ◽  
And Function

The La and the La-related protein (LARP) superfamily is a diverse class of RNA binding proteins involved in RNA processing, folding, and function. Larp7 binds to the abundant long noncoding 7SK RNA and is required for 7SK ribonucleoprotein (RNP) assembly and function. The 7SK RNP sequesters a pool of the positive transcription elongation factor b (P-TEFb) in an inactive state; on release, P-TEFb phosphorylates RNA Polymerase II to stimulate transcription elongation. Despite its essential role in transcription, limited structural information is available for the 7SK RNP, particularly for protein–RNA interactions. Larp7 contains an N-terminal La module that binds UUU-3′OH and a C-terminal atypical RNA recognition motif (xRRM) required for specific binding to 7SK and P-TEFb assembly. Deletion of the xRRM is linked to gastric cancer in humans. We report the 2.2-Å X-ray crystal structure of the human La-related protein group 7 (hLarp7) xRRM bound to the 7SK stem-loop 4, revealing a unique binding interface. Contributions of observed interactions to binding affinity were investigated by mutagenesis and isothermal titration calorimetry. NMR 13C spin relaxation data and comparison of free xRRM, RNA, and xRRM–RNA structures show that the xRRM is preordered to bind a flexible loop 4. Combining structures of the hLarp7 La module and the xRRM–7SK complex presented here, we propose a structural model for Larp7 binding to the 7SK 3′ end and mechanism for 7SK RNP assembly. This work provides insight into how this domain contributes to 7SK recognition and assembly of the core 7SK RNP.

Domain necessary for Drosophila ELAV nuclear localization: function requires nuclear ELAV

1999 ◽  
Vol 112 (24) ◽  
pp. 4501-4512 ◽  
Author(s):  
Y.M. Yannoni ◽  
K. White
Keyword(s):  
Nuclear Localization ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Nuclear Localization Sequence ◽  
Rna Recognition ◽  
Rna Recognition Motifs ◽  
Mutant Proteins ◽  
Localization Sequence ◽  
Recognition Motifs

The neuron specific Drosophila ELAV protein belongs to the ELAV family of RNA binding proteins which are characterized by three highly conserved RNA recognition motifs, an N-terminal domain, and a hinge region between the second and third RNA recognition motifs. Despite their highly conserved RNA recognition motifs the ELAV family members are a group of proteins with diverse posttranscriptional functions including splicing regulation, mRNA stability and translatability and have a variety of subcellular localizations. The role of the ELAV hinge in localization and function was examined using transgenes encoding ELAV hinge deletions, in vivo. Subcellular localization of the hinge mutant proteins revealed that residues between amino acids 333–374 are necessary for nuclear localization. This delineated sequence has no significant homology to classical nuclear localization sequences, but it is similar to the recently characterized nucleocytoplasmic shuttling sequence, the HNS, from a human ELAV family member, HuR. This defined sequence, however, was insufficient for nuclear localization as tested using hinge-GFP fusion proteins. Functional assays revealed that mutant proteins that fail to localize to the nucleus are unable to provide ELAV vital function, but their function is significantly restored when translocated into the nucleus by a heterologous nuclear localization sequence tag.

PUB1: a major yeast poly(A)+ RNA-binding protein

1993 ◽  
Vol 13 (10) ◽  
pp. 6114-6123
Author(s):  
M J Matunis ◽  
E L Matunis ◽  
G Dreyfuss
Keyword(s):  
Rna Polymerase Ii ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Uv Light ◽  
Binding Protein ◽  
Gene Replacement ◽  
Yeast Saccharomyces Cerevisiae ◽  
Binding Domains ◽  
Development And Differentiation

The expression of RNA polymerase II transcripts can be regulated at the posttranscriptional level by RNA-binding proteins. Although extensively characterized in metazoans, relatively few RNA-binding proteins have been characterized in the yeast Saccharomyces cerevisiae. Three major proteins are cross-linked by UV light to poly(A)+ RNA in living S. cerevisiae cells. These are the 72-kDa poly(A)-binding protein and proteins of 60 and 50 kDa (S.A. Adam, T.Y. Nakagawa, M.S. Swanson, T. Woodruff, and G. Dreyfuss, Mol. Cell. Biol. 6:2932-2943, 1986). Here, we describe the 60-kDa protein, one of the major poly(A)+ RNA-binding proteins in S. cerevisiae. This protein, PUB1 [for poly(U)-binding protein 1], was purified by affinity chromatography on immobilized poly(rU), and specific monoclonal antibodies to it were produced. UV cross-linking demonstrated that PUB1 is bound to poly(A)+ RNA (mRNA or pre-mRNA) in living cells, and it was detected primarily in the cytoplasm by indirect immunofluorescence. The gene for PUB1 was cloned and sequenced, and the sequence was found to predict a 51-kDa protein with three ribonucleoprotein consensus RNA-binding domains and three glutamine- and asparagine-rich auxiliary domains. This overall structure is remarkably similar to the structures of the Drosophila melanogaster elav gene product, the human neuronal antigen HuD, and the cytolytic lymphocyte protein TIA-1. Each of these proteins has an important role in development and differentiation, potentially by affecting RNA processing. PUB1 was found to be nonessential in S. cerevisiae by gene replacement; however, further genetic analysis should reveal important features of this class of RNA-binding proteins.

Targeting of transcripts encoding membrane proteins in polarized epithelia: RNA–protein binding studies of the SGLT1 3′-UTR

2008 ◽  
Vol 36 (3) ◽  
pp. 525-527 ◽  
Author(s):  
Christopher M. Pedder ◽  
Dianne Ford ◽  
John E. Hesketh
Keyword(s):  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Protein Localization ◽  
Complex Structure ◽  
Mrna Translation ◽  
Drosophila Embryo ◽  
Binding Studies ◽  
Polarized Epithelia ◽  
Apical Localization

mRNA stability, mRNA translation and spatial localization of mRNA species within a cell can be governed by signals in the 3′-UTR (3′-untranslated region). Local translation of proteins is essential for the development of many eukaryotic cell types, such as the Drosophila embryo, where the spatial and temporal localization of bicoid and gurken mRNAs, among others, is required to establish morphogen gradients. More recent studies have suggested that mRNA localization also occurs with transcripts coding for membrane-based or secreted proteins, and that localization at organelles such as the endoplasmic reticulum directs translation more efficiently to specific subdomains, so as to aid correct protein localization. In human epithelial cells, the mRNA coding for SGLT1 (sodium–glucose co-transporter 1), an apical membrane protein, has been shown to be localized apically in polarized cells. However, the nature of the signals and RNA-binding proteins involved are unknown. Ongoing work is aimed at identifying the localization signals in the SGLT1 3′-UTR and the corresponding binding proteins. Using a protein extract from polarized Caco-2 cells, both EMSAs (electrophoretic mobility-shift assays) and UV cross-linking assays have shown that a specific protein complex is formed with the first 300 bases of the 3′-UTR sequence. MFold predictions suggest that this region folds into a complex structure and ongoing studies using a series of strategic deletions are being carried out to identify the precise nature of the motif involved, particularly the role of the sequence or RNA secondary structure, as well as to identify the main proteins present within the complex. Such information will provide details of the post-transcriptional events that lead to apical localization of the SGLT1 transcript and may reveal mechanisms of more fundamental importance in the apical localization of proteins in polarized epithelia.

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