Putative RNA-binding Protein Research Articles

A Puf RNA-binding protein encoding gene PlM90 regulates the sexual and asexual life stages of the litchi downy blight pathogen Peronophythora litchii

Sexual and asexual reproduction are two key processes in the pathogenic cycle of many filamentous pathogens. However in Peronophythora litchii, the causal pathogen for the litchi downy blight disease, critical regulator(s) of sexual or asexual differentiation has not been elucidated. In this study, we cloned a gene named PlM90 from P. litchii, which encodes a putative Puf RNA-binding protein. We found that PlM90 was highly expressed during asexual development, and much higher than that during sexual development, while relatively lower during cyst germination and plant infection. By polyethylene glycol (PEG)-mediated protoplast transformation, we generated three PlM90-silenced transformants and found a severely impaired ability in sexual spore production and a delay in stages of zoospore release and encystment. However, the pathogenicity of P. litchii was not affected by PlM90-silencing. Therefore we conclude that PlM90 specifically regulates the sexual and asexual differentiation of P. litchii.

Exosome Proteome of U-87MG Glioblastoma Cells.

Exosomes are small membrane vesicles between 30 and 100 nm in diameter secreted by many cell types, and are associated with a wide range of physiological and/or pathological processes. Exosomes containing proteins, lipids, mRNA, and microRNA contribute to cell-to-cell communication and cell-to-environment regulation, however, their biological functions are not yet fully understood. In this report, exosomes in the glioblastoma cell line, U-87MG, were isolated and the proteome was investigated. In addition, exosome proteome changes in U-87MG cells exposed to a low temperature were investigated to elucidate whether the exosome proteome could respond to an external stimulus. Cell culture medium was collected, and exosomes were isolated by continuous centrifugation eliminating cell debris, nucleic acids, and other particles. The morphology of exosomes was observed by cryo-tunneling electron microscopy. According to 2-dimensional electrophoresis and matrix-assisted laser desorption ionization time-of-flight mass spectrometry, certain proteins including collagen type VI alpha 1, putative RNA-binding protein 15B chain A, substrate induced remodeling of the active site regulates HTRA1, coatomer protein complex-subunit beta 2, myosin-heavy chain 1, and keratin-type I cytoskeletal 9 showed differences between the control proteome and the low temperature-exposed proteome.

Characterization of pneumococcal Ser/Thr protein phosphatase phpP mutant and identification of a novel PhpP substrate, putative RNA binding protein Jag.

BackgroundReversible protein phosphorylation catalyzed by protein kinases and phosphatases is the primary mechanism for signal transduction in all living organisms. Streptococcus pneumoniae encodes a single Ser/Thr protein kinase, StkP, which plays a role in virulence, stress resistance and the regulation of cell wall synthesis and cell division. However, the role of its cognate phosphatase, PhpP, is not well defined.ResultsHere, we report the successful construction of a ΔphpP mutant in the unencapsulated S. pneumoniae Rx1 strain and the characterization of its phenotype. We demonstrate that PhpP negatively controls the level of protein phosphorylation in S. pneumoniae both by direct dephosphorylation of target proteins and by dephosphorylation of its cognate kinase, StkP. Catalytic inactivation or absence of PhpP resulted in the hyperphosphorylation of StkP substrates and specific phenotypic changes, including sensitivity to environmental stresses and competence deficiency. The morphology of the ΔphpP cells resembled the StkP overexpression phenotype and conversely, overexpression of PhpP resulted in cell elongation mimicking the stkP null phenotype. Proteomic analysis of the phpP knock-out strain permitted identification of a novel StkP/PhpP substrate, Spr1851, a putative RNA-binding protein homologous to Jag. Here, we show that pneumococcal Jag is phosphorylated on Thr89. Inactivation of jag confers a phenotype similar to the phpP mutant strain.ConclusionsOur results suggest that PhpP and StkP cooperatively regulate cell division of S. pneumoniae and phosphorylate putative RNA binding protein Jag.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-016-0865-6) contains supplementary material, which is available to authorized users.

RStrucFam: a web server to associate structure and cognate RNA for RNA-binding proteins from sequence information.

BackgroundRNA-binding proteins (RBPs) interact with their cognate RNA(s) to form large biomolecular assemblies. They are versatile in their functionality and are involved in a myriad of processes inside the cell. RBPs with similar structural features and common biological functions are grouped together into families and superfamilies. It will be useful to obtain an early understanding and association of RNA-binding property of sequences of gene products. Here, we report a web server, RStrucFam, to predict the structure, type of cognate RNA(s) and function(s) of proteins, where possible, from mere sequence information.ResultsThe web server employs Hidden Markov Model scan (hmmscan) to enable association to a back-end database of structural and sequence families. The database (HMMRBP) comprises of 437 HMMs of RBP families of known structure that have been generated using structure-based sequence alignments and 746 sequence-centric RBP family HMMs. The input protein sequence is associated with structural or sequence domain families, if structure or sequence signatures exist. In case of association of the protein with a family of known structures, output features like, multiple structure-based sequence alignment (MSSA) of the query with all others members of that family is provided. Further, cognate RNA partner(s) for that protein, Gene Ontology (GO) annotations, if any and a homology model of the protein can be obtained. The users can also browse through the database for details pertaining to each family, protein or RNA and their related information based on keyword search or RNA motif search.ConclusionsRStrucFam is a web server that exploits structurally conserved features of RBPs, derived from known family members and imprinted in mathematical profiles, to predict putative RBPs from sequence information. Proteins that fail to associate with such structure-centric families are further queried against the sequence-centric RBP family HMMs in the HMMRBP database. Further, all other essential information pertaining to an RBP, like overall function annotations, are provided. The web server can be accessed at the following link: http://caps.ncbs.res.in/rstrucfam.Electronic supplementary materialThe online version of this article (doi:10.1186/s12859-016-1289-x) contains supplementary material, which is available to authorized users.

Heterologous expression of an RNA-binding protein affects flowering time as well as other developmental processes in Solanaceae

Flowering time in members of the Solanaceae plant family, such as pepper (Capsicum spp.) and tomato (Solanum lycopersicum), is an important agronomic trait for controlling shoot architecture and improving yield. To investigate the feasibility of flowering time regulation in tomato, an RNA-binding protein (RBP) encoding gene homologous to human Nucleolar protein interacting with the forkhead-associated (FHA) domain of pKI-67 (NIFK), CaRBP, was isolated from hot pepper. The function of CaRBP was determined in transgenic tomato. The deduced amino acid sequence includes an RNA recognition motif (RRM) and showed most similarity to the RRM present in a putative RBP encoded by human NIFK. CaRBP was highly expressed in the vegetative and reproductive tissues, such as leaves and fruits, respectively. Subcellular localization analysis indicated that CaRBP is a nucleolar protein. Heterologous expression of CaRBP under 35S promoter in tomato plants induced severe alteration of flowering with additional defects of vegetative organs. This floral retardation was associated with the alteration of SFT/SP3D and SlSOC1s as floral integrators. Furthermore, CaRBP reduces the expression levels of SlCOLs/TCOLs via changes in the expression of SlCDF3, SlFBHs, and SlFKF1s. This indicates a repressive effect of CaRBP on the regulation of flowering time in tomato. Overall, these results suggest that alteration in CaRBP expression levels may provide an effective means of controlling flowering time in day-neutral Solanaceae.

Genome-wide survey of putative RNA-binding proteins encoded in the human proteome.

RNA-binding proteins (RBPs) are involved in various post-transcriptional gene regulatory processes and are also functionally important members of the ribosome and the spliceosome. However, RBPs and their interactions with RNA are less well-studied in comparison to DNA-binding proteins. We have classified the existing RBP structures, available in complexes with RNA and RNA/DNA hybrids, into different structural families and created Hidden Markov Models (HMMs). These structure-centric family HMMs, along with the sequence-centric family HMMs, were used as a primary database to systematically search the human proteome for the presence of putative RBPs. We have found more than 2600 gene products with RBP signatures in humans, of which around 28% are likely to bind to RNA but not DNA, whereas 9% might bind to both RNA and DNA. 11% of them do not contain an explicit functional annotation yet. Nearly 30% of the putative RBPs are exclusively nuclear, 15% have known disease associations and around 30% are enzymes. Around 40% of the proteins identified in this study are novel and have not been reported by recent large-scale studies on human RBPs.

A bioinformatic survey of RNA-binding proteins in Plasmodium.

BackgroundThe malaria parasites in the genus Plasmodium have a very complicated life cycle involving an invertebrate vector and a vertebrate host. RNA-binding proteins (RBPs) are critical factors involved in every aspect of the development of these parasites. However, very few RBPs have been functionally characterized to date in the human parasite Plasmodium falciparum.MethodsUsing different bioinformatic methods and tools we searched P. falciparum genome to list and annotate RBPs. A representative 3D models for each of the RBD domain identified in P. falciparum was created using I-TESSAR and SWISS-MODEL. Microarray and RNAseq data analysis pertaining PfRBPs was performed using MeV software. Finally, Cytoscape was used to create protein-protein interaction network for CITH-Dozi and Caf1-CCR4-Not complexes.ResultsWe report the identification of 189 putative RBP genes belonging to 13 different families in Plasmodium, which comprise 3.5 % of all annotated genes. Almost 90 % (169/189) of these genes belong to six prominent RBP classes, namely RNA recognition motifs, DEAD/H-box RNA helicases, K homology, Zinc finger, Puf and Alba gene families. Interestingly, almost all of the identified RNA-binding helicases and KH genes have cognate homologs in model species, suggesting their evolutionary conservation. Exploration of the existing P. falciparum blood-stage transcriptomes revealed that most RBPs have peak mRNA expression levels early during the intraerythrocytic development cycle, which taper off in later stages. Nearly 27 % of RBPs have elevated expression in gametocytes, while 47 and 24 % have elevated mRNA expression in ookinete and asexual stages. Comparative interactome analyses using human and Plasmodium protein-protein interaction datasets suggest extensive conservation of the PfCITH/PfDOZI and PfCaf1-CCR4-NOT complexes.ConclusionsThe Plasmodium parasites possess a large number of putative RBPs belonging to most of RBP families identified so far, suggesting the presence of extensive post-transcriptional regulation in these parasites. Taken together, in silico identification of these putative RBPs provides a foundation for future functional studies aimed at defining a unique network of post-transcriptional regulation in P. falciparum.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-2092-1) contains supplementary material, which is available to authorized users.

Reagent and Data Resources for Investigation of RNA Binding Protein Functions in Drosophila melanogaster Cultured Cells.

RNA binding proteins (RBPs) are involved in many cellular functions. To facilitate functional characterization of RBPs, we generated an RNA interference (RNAi) library for Drosophila cell-based screens comprising reagents targeting known or putative RBPs. To test the quality of the library and provide a baseline analysis of the effects of the RNAi reagents on viability, we screened the library using a total ATP assay and high-throughput imaging in Drosophila S2R+ cultured cells. The results are consistent with production of a high-quality library that will be useful for functional genomics studies using other assays. Altogether, we provide resources in the form of an initial curated list of Drosophila RBPs; an RNAi screening library we expect to be used with additional assays that address more specific biological questions; and total ATP and image data useful for comparison of those additional assay results with fundamental information such as effects of a given reagent in the library on cell viability. Importantly, we make the baseline data, including more than 200,000 images, easily accessible online.

Novel roles for LIX1L in promoting cancer cell proliferation through ROS1-mediated LIX1L phosphorylation.

Herein, we report the characterization of Limb expression 1-like, (LIX1L), a putative RNA-binding protein (RBP) containing a double-stranded RNA binding motif, which is highly expressed in various cancer tissues. Analysis of MALDI-TOF/TOF mass spectrometry and RNA immunoprecipitation-sequencing of interacting proteins and the microRNAs (miRNAs) bound to LIX1L revealed that LIX1L interacts with proteins (RIOK1, nucleolin and PABPC4) and miRNAs (has-miRNA-520a-5p, −300, −216b, −326, −190a, −548b-3p, −7–5p and −1296) in HEK-293 cells. Moreover, the reduction of phosphorylated Tyr136 (pTyr136) in LIX1L through the homeodomain peptide, PY136, inhibited LIX1L-induced cell proliferation in vitro, and PY136 inhibited MKN45 cell proliferation in vivo. We also determined the miRNA-targeted genes and showed that was apoptosis induced through the reduction of pTyr136. Moreover, ROS1, HCK, ABL1, ABL2, JAK3, LCK and TYR03 were identified as candidate kinases responsible for the phosphorylation of Tyr136 of LIX1L. These data provide novel insights into the biological significance of LIX1L, suggesting that this protein might be an RBP, with implications for therapeutic approaches for targeting LIX1L in LIX1L-expressing cancer cells.

Study of mRNA turnover never decays.

Study of mRNA turnover never decays.

Identification of genes that may regulate the expression of the transcription factor production of anthocyanin pigment 1 (PAP1)/MYB75 involved in Arabidopsis anthocyanin biosynthesis.

A putative RNA-binding protein with a single RNA Recognition Motif (At3G63450) is involved in anthocyanin biosynthesis via its ability to modulate the transcript level of a major positive regulator PAP1 in Arabidopsis. The R2R3 MYB-activator production of anthocyanin pigment 1 (PAP1)/MYB75 plays a major role in anthocyanin biosynthesis in Arabidopsis in combination with one of three bHLH activators including transparent test 8 (TT8), enhancer of glabra3 (EGL3), glabra3 (GL3), and the WD-repeat transcription factor transparent testa 1 (TTG1), forming ternary MYB-basic HLH-WD40 complexes. Transcriptional activation of PAP1 expression is largely triggered by changes in light color and intensity, temperature fluctuations, nutrient status, and sugar and hormone treatments. However, the immediate upstream and downstream regulatory factors for PAP1 transcription are largely unknown. In the present study, using a T-DNA insertional mutagenesis approach, we transformed pap1-Dominant (pap1D) plants to modulate the levels of endogenous PAP1 transcripts. We employed Restriction Site Extension (RSE)-PCR analysis of 247 homogenous T3 genetic mutant lines exhibiting variations in anthocyanin accumulation compared to pap1D and identified 92 lines with T-DNA integrated in either intra- or inter-genic locations. This analysis revealed 80 novel candidate proteins, including a putative RNA-binding protein with a single RNA Recognition Motif (At3G63450), which may directly or indirectly regulate PAP1 expression at the transcriptional level.

Global Analysis of the RNA-Protein Interaction and RNA Secondary Structure Landscapes of the Arabidopsis Nucleus

Posttranscriptional regulation in eukaryotes requires cis- and trans-acting features and factors including RNA secondary structure and RNA-binding proteins (RBPs). However, a comprehensive view of the structural and RBP interaction landscape of nuclear RNAs has yet to be compiled for any organism. Here, we use our ribonuclease-mediated structure and RBP-binding site mapping approaches to globally profile these features in Arabidopsis seedling nuclei in vivo. We reveal anticorrelated patterns of secondary structure and RBP binding throughout nuclear mRNAs that demarcate sites of alternative splicing and polyadenylation. We also uncover a collection of protein-bound sequence motifs, and identify their structural contexts, co-occurrences in transcripts encoding functionally related proteins, and interactions with putative RBPs. Finally, using these motifs, we find that the chloroplast RBP CP29A also interacts with nuclear mRNAs. In total, we provide a simultaneous view of the RNA secondary structure and RBP interaction landscapes in a eukaryotic nucleus.

BREX is a novel phage resistance system widespread in microbial genomes.

The perpetual arms race between bacteria and phage has resulted in the evolution of efficient resistance systems that protect bacteria from phage infection. Such systems, which include the CRISPR-Cas and restriction-modification systems, have proven to be invaluable in the biotechnology and dairy industries. Here, we report on a six-gene cassette in Bacillus cereus which, when integrated into the Bacillus subtilis genome, confers resistance to a broad range of phages, including both virulent and temperate ones. This cassette includes a putative Lon-like protease, an alkaline phosphatase domain protein, a putative RNA-binding protein, a DNA methylase, an ATPase-domain protein, and a protein of unknown function. We denote this novel defense system BREX (Bacteriophage Exclusion) and show that it allows phage adsorption but blocks phage DNA replication. Furthermore, our results suggest that methylation on non-palindromic TAGGAG motifs in the bacterial genome guides self/non-self discrimination and is essential for the defensive function of the BREX system. However, unlike restriction-modification systems, phage DNA does not appear to be cleaved or degraded by BREX, suggesting a novel mechanism of defense. Pan genomic analysis revealed that BREX and BREX-like systems, including the distantly related Pgl system described in Streptomyces coelicolor, are widely distributed in ~10% of all sequenced microbial genomes and can be divided into six coherent subtypes in which the gene composition and order is conserved. Finally, we detected a phage family that evades the BREX defense, implying that anti-BREX mechanisms may have evolved in some phages as part of their arms race with bacteria.

Three RNA binding proteins form a complex to promote differentiation of germline stem cell lineage in Drosophila.

In regenerative tissues, one of the strategies to protect stem cells from genetic aberrations, potentially caused by frequent cell division, is to transiently expand the stem cell daughters before further differentiation. However, failure to exit the transit amplification may lead to overgrowth, and the molecular mechanism governing this regulation remains vague. In a Drosophila mutagenesis screen for factors involved in the regulation of germline stem cell (GSC) lineage, we isolated a mutation in the gene CG32364, which encodes a putative RNA-binding protein (RBP) and is designated as tumorous testis (tut). In tut mutant, spermatogonia fail to differentiate and over-amplify, a phenotype similar to that in mei-P26 mutant. Mei-P26 is a TRIM-NHL tumor suppressor homolog required for the differentiation of GSC lineage. We found that Tut binds preferentially a long isoform of mei-P26 3′UTR, and is essential for the translational repression of mei-P26 reporter. Bam and Bgcn are both RBPs that have also been shown to repress mei-P26 expression. Our genetic analyses indicate that tut, bam, or bgcn is required to repress mei-P26 and to promote the differentiation of GSCs. Biochemically, we demonstrate that Tut, Bam, and Bgcn can form a physical complex in which Bam holds Tut on its N-terminus and Bgcn on its C-terminus. Our in vivo and in vitro evidence illustrate that Tut acts with Bam, Bgcn to accurately coordinate proliferation and differentiation in Drosophila germline stem cell lineage.

The Drosophila lingerer protein cooperates with Orb2 in long-term memory formation

Recently mated Drosophila females were shown to be reluctant to copulate and to exhibit rejecting behavior when courted by a male. Males that experience mate refusal by a mated female subsequently attenuate their courtship effort toward not only mated females but also virgin females. This courtship suppression persists for more than a day, and thus represents long-term memory. The courtship long-term memory has been shown to be impaired in heterozygotes as well as homozygotes of mutants in orb2, a locus encoding a set of CPEB RNA-binding proteins. We show that the impaired courtship long-term memory in orb2-mutant heterozygotes is restored by reducing the activity of lig, another putative RNA-binding protein gene, yet on its own the loss-of-function lig mutation is without effect. We further show that Lig forms a complex with Orb2. We infer that a reduction in the Lig levels compensates the Orb2 deficiency by mitigating the negative feedback for Orb2 expression and thereby alleviating defects in long-term memory.

Proteomic analysis of cap-dependent translation identifies LARP1 as a key regulator of 5′TOP mRNA translation

The mammalian target of rapamycin (mTOR) promotes cell growth and proliferation by promoting mRNA translation and increasing the protein synthetic capacity of the cell. Although mTOR globally promotes translation by regulating the mRNA 5' cap-binding protein eIF4E (eukaryotic initiation factor 4E), it also preferentially regulates the translation of certain classes of mRNA via unclear mechanisms. To help fill this gap in knowledge, we performed a quantitative proteomic screen to identify proteins that associate with the mRNA 5' cap in an mTOR-dependent manner. Using this approach, we identified many potential regulatory factors, including the putative RNA-binding protein LARP1 (La-related protein 1). Our results indicate that LARP1 associates with actively translating ribosomes via PABP and that LARP1 stimulates the translation of mRNAs containing a 5' terminal oligopyrimidine (TOP) motif, encoding for components of the translational machinery. We found that LARP1 associates with the mTOR complex 1 (mTORC1) and is required for global protein synthesis as well as cell growth and proliferation. Together, these data reveal important molecular mechanisms involved in TOP mRNA translation and implicate LARP1 as an important regulator of cell growth and proliferation.

Genome-wide dissection of the quorum sensing signalling pathway in Trypanosoma brucei

The protozoan parasites Trypanosoma brucei spp. cause important human and livestock diseases in sub Saharan Africa. In the mammalian blood, two developmental forms of the parasite exist: proliferative ‘slender’ forms and arrested ‘stumpy’ forms that are responsible for transmission to tsetse flies. The slender to stumpy differentiation is a density-dependent response that resembles quorum sensing (QS) in microbial systems and is crucial for the parasite life cycle, ensuring both infection chronicity and disease transmission1. This response is triggered by an elusive ‘stumpy induction factor’ (SIF) whose intracellular signaling pathway is also uncharacterized. Laboratory-adapted (monomorphic) trypanosome strains respond inefficiently to SIF but can generate forms with stumpy characteristics when exposed to cell permeable cAMP and AMP analogues. Exploiting this, we have used a genome-wide RNAi library screen to identify the signaling components driving stumpy formation. In separate screens, monomorphic parasites were exposed to 8-(4-chlorophenylthio)-cAMP (pCPTcAMP) or 8-pCPT-2′-O-Me-5′-AMP to select cells that were unresponsive to these signals and hence remained proliferative. Genome-wide ion torrent-based RNA interference Target sequencing identified cohorts of genes implicated in each step of the signaling pathway, from purine metabolism, through signal transducers (kinases, phosphatases) to gene expression regulators. Genes at each step were independently validated in cells naturally capable of stumpy formation, confirming their role in density sensing in vivo, whilst the putative RNA-binding protein, RBP7, was required for normal QS and promoted cell-cycle arrest and transmission competence when overexpressed. This study reveals that QS signaling in trypanosomes shares similarities to fundamental quiescence pathways in eukaryotic cells, its components providing targets for QS-interference based therapeutics.

Nitrogen Oxyanion-dependent Dissociation of a Two-component Complex That Regulates Bacterial Nitrate Assimilation

Nitrogen is an essential nutrient for growth and is readily available to microbes in many environments in the form of ammonium and nitrate. Both ions are of environmental significance due to sustained use of inorganic fertilizers on agricultural soils. Diverse species of bacteria that have an assimilatory nitrate/nitrite reductase system (NAS) can use nitrate or nitrite as the sole nitrogen source for growth when ammonium is limited. In Paracoccus denitrificans, the pathway-specific two-component regulator for NAS expression is encoded by the nasT and nasS genes. Here, we show that the putative RNA-binding protein NasT is a positive regulator essential for expression of the nas gene cluster (i.e. nasABGHC). By contrast, a nitrogen oxyanion-binding sensor (NasS) is required for nitrate/nitrite-responsive control of nas gene expression. The NasS and NasT proteins co-purify as a stable heterotetrameric regulatory complex, NasS-NasT. This protein-protein interaction is sensitive to nitrate and nitrite, which cause dissociation of the NasS-NasT complex into monomeric NasS and an oligomeric form of NasT. NasT has been shown to bind the leader RNA for nasA. Thus, upon liberation from the complex, the positive regulator NasT is free to up-regulate nas gene expression.

Post-transcriptional regulation of myotube elongation and myogenesis by Hoi Polloi

Striated muscle development requires the coordinated expression of genes involved in sarcomere formation and contractility, as well as genes that determine muscle morphology. However, relatively little is known about the molecular mechanisms that control the early stages of muscle morphogenesis. To explore this facet of myogenesis, we performed a genetic screen for regulators of somatic muscle morphology in Drosophila, and identified the putative RNA-binding protein (RBP) Hoi Polloi (Hoip). Hoip is expressed in striated muscle precursors within the muscle lineage and controls two genetically separable events: myotube elongation and sarcomeric protein expression. Myotubes fail to elongate in hoip mutant embryos, even though the known regulators of somatic muscle elongation, target recognition and muscle attachment are expressed normally. In addition, a majority of sarcomeric proteins, including Myosin Heavy Chain (MHC) and Tropomyosin, require Hoip for their expression. A transgenic MHC construct that contains the endogenous MHC promoter and a spliced open reading frame rescues MHC protein expression in hoip embryos, demonstrating the involvement of Hoip in pre-mRNA splicing, but not in transcription, of muscle structural genes. In addition, the human Hoip ortholog NHP2L1 rescues muscle defects in hoip embryos, and knockdown of endogenous nhp2l1 in zebrafish disrupts skeletal muscle development. We conclude that Hoip is a conserved, post-transcriptional regulator of muscle morphogenesis and structural gene expression.

RNA-binding proteins associated with desiccation during seed development in rice

Long-lived mRNAs stored in mature seeds can remain active for long periods even if seeds undergo severe desiccation. They are then translated at the initiation of germination. To clarify the mechanism for stabilization of long-lived mRNAs during seed desiccation, fluctuations in RNA-binding protein (RBP) profiles that occur during seed formation in rice were analyzed. Proteomic analysis revealed that glycine-rich RBP 1A (GRP1A) is a highly abundant RBP in mature rice seeds. In addition, real-time RT-PCR analysis showed that putative RBP RZ-1A (RZ-1A) is seed specific. Moreover, transcripts of these two RBPs were clearly up-regulated during desiccation in rice seeds. The features of these two RBPs resemble those of late embryogenesis abundant proteins that function as molecular chaperones in dry seeds. Therefore, GRP1A and RZ-1A may have important roles in the stability of long-lived mRNAs in rice seeds.