Polycytosine RNA-binding protein 1 regulates osteoblast function via a ferroptosis pathway in type 2 diabetic osteoporosis

BACKGROUND Recently,type 2 diabetic osteoporosis(T2DOP)has become a research hotspot for the complications of diabetes,but the specific mechanism of its occurrence and development remains unknown.Ferroptosis caused by iron overload is con-sidered an important cause of T2DOP.Polycytosine RNA-binding protein 1(PCBP1),an iron ion chaperone,is considered a protector of ferroptosis.AIM To investigate the existence of ferroptosis and specific role of PCBP1 in the development of type 2 diabetes.METHODS A cell counting kit-8 assay was used to detect changes in osteoblast viability under high glucose(HG)and/or ferroptosis inhibitors at different concentrations and times.Transmission electron microscopy was used to examine the morpho-logical changes in the mitochondria of osteoblasts under HG,and western blotting was used to detect the expression levels of PCBP1,ferritin,and the ferroptosis-related protein glutathione peroxidase 4(GPX4).A lentivirus silenced and overex-pressed PCBP1.Western blotting was used to detect the expression levels of the osteoblast functional proteins osteoprotegerin(OPG)and osteocalcin(OCN),whereas flow cytometry was used to detect changes in reactive oxygen species(ROS)levels in each group.RESULTS Under HG,the viability of osteoblasts was considerably decreased,the number of mitochondria undergoing atrophy was considerably increased,PCBP1 and ferritin expression levels were increased,and GPX4 expression was decreased.Western blotting results demonstrated that infection with lentivirus overexpressing PCBP1,increased the expression levels of ferritin,GPX4,OPG,and OCN,compared with the HG group.Flow cytometry results showed a reduction in ROS,and an opposite result was obtained after silencing PCBP1.CONCLUSION PCBP1 may protect osteoblasts and reduce the harm caused by ferroptosis by promoting ferritin expression under a HG environment.Moreover,PCBP1 may be a potential therapeutic target for T2DOP.

Construction and Verification of an RNA-Binding Protein-Associated Prognostic Model for Gliomas

Objective To construct and verificate an RNA-binding protein(RBP)-associated prognostic model for gliomas using integrated bioinformatics analysis.Methods RNA-sequencing and clinic pathological data of glioma patients from The Cancer Genome Atlas(TCGA)database and the Chinese Glioma Genome Atlas database(CGGA)were downloaded.The aberrantly expressed RBPs were investigated between gliomas and normal samples in TCGA database.We then identified prognosis related hub genes and constructed a prognostic model.This model was further validated in the CGGA-693 and CGGA-325 cohorts.Results Totally 174 differently expressed genes-encoded RBPs were identified,containing 85 down-regulated and 89 up-regulated genes.We identified five genes-encoded RBPs(ERI1,RPS2,BRCA1,NXT1,and TRIM21)as prognosis related key genes and constructed a prognostic model.Overall survival(OS)analysis revealed that the patients in the high-risk subgroup based on the model were worse than those in the low-risk subgroup.The area under the receiver operator characteristic curve(AUC)of the prognostic model was 0.836 in the TCGA dataset and 0.708 in the CGGA-693 dataset,demonstrating a favorable prognostic model.Survival analyses of the five RBPs in the CGGA-325 cohort validated the findings.A nomogram was constructed based on the five genes and validated in the TCGA cohort,confirming a promising discriminating ability for gliomas.Conclusion The prognostic model of the five RBPs might serve as an independent prognostic algorithm for gliomas.

LEAFY HEAD2,which encodes a putative RNA-binding protein,regulates shoot development of rice

During vegetative development, higher plants continuously form new leaves in regular spatial and temporal patterns. Mutants with abnormal leaf developmental patterns not only provide a great insight into understanding the regulatory mechanism of plant architecture, but also enrich the ways to its modification by which crop yield could be improved. Here, we reported the characterization of the rice leafy-head2 （lhd2） mutant that exhibits shortened plastochron, dwarfism, reduced tiller number, and failure of phase transition from vegetative to reproductive growth. Anatomical and histological study revealed that the rapid emergence of leaves in lhd2 was resulted from the rapid initiation of leaf primordia whereas the reduced tiller number was a consequence of the suppression of the tiller bud outgrowth. The molecular and genetic analysis showed that LHD2 encodes a putative RNA binding protein with 67% similarity to maize TEl. Comparison of genome-scale expression profiles between wild-type and lhd2 plants suggested that LHD2 may regulate rice shoot development through KNOXand hormone-related genes. The similar phenotypes caused by LHD2 mutation and the conserved expression pattern of LHD2 indicated a conserved mechanism in controlling the temporal leaf initiation in grass.

Neuroprotective effects of cold-inducible RNA-binding protein during mild hypothermia on traumatic brain injury

Cold-inducible RNA-binding protein（CIRP）, a key regulatory protein, could be facilitated by mild hypothermia in the brain, heart and liver. This study observed the effects of mild hypothermia at 31 ± 0.5℃ on traumatic brain injury in rats. Results demonstrated that mild hypothermia suppressed apoptosis in the cortex, hippocampus and hypothalamus, facilitated CIRP m RNA and protein expression in these regions, especially in the hypothalamus. The anti-apoptotic effect of mild hypothermia disappeared after CIRP silencing. There was no correlation between mitogen-activated extracellular signal-regulated kinase activation and CIRP silencing. CIRP silencing inhibited extracellular signal-regulated kinase-1/2 activation. These indicate that CIRP inhibits apoptosis by affecting extracellular signal-regulated kinase-1/2 activation, and exerts a neuroprotective effect during mild hypothermia for traumatic brain injury.

Downregulation of cold-inducible RNA-binding protein activates mitogen-activated protein kinases and impairs spermatoRenic function in mouse testes

Cold-inducible RNA-binding protein （CIRP） is an RNA-binding protein that is expressed in normal testes and downregulated after heat stress caused by cryptorchidism, varicocele or environmental temperatures. The purpose of this study was to investigate the functions of CIRP in the testes. We employed RNAi technique to knock down the expression of CIRP in the testes, and performed haematoxylin and eosin staining to evaluate morphological changes following knockdown. Germ cell apoptosis was examined by terminal deoxynucleotidal transferase-mediated dUTP nick end labelling （TUNEL） assay, and mitogen-activated protein kinase （MAPK） signalling pathways were investigated by Western blotting to determine the possible mechanism of apoptosis. We found that using siRNA is a feasible and reliable method for knocking down gene expression in the testes. Compared to controls, the mean seminiferous tubule diameter （MSTD） and the thickness of the germ cell layers decreased following siRNA treatment, whereas the percentage of apoptotic seminiferous tubules increased. The p44/p42, p38 and SAPK/JNK MAPK pathways were activated after downregulation of CIRP. In conclusion, we discovered that downregulation of CIRP resulted in increased germ cell apoptosis, possibly viathe activation of the p44/p42, p38 and SAPK/JNK MAPK pathways.

Characterization and Expression Analysis of Four Glycine-Rich RNA-Binding Proteins Involved in Osmotic Response in Tobacco (Nicotiana tabacum cv. Xanthi)

Plants have developed many signals and specific genes＇ regulations at both transcriptional and post-transcriptional levels in order to tolerate and adapt to various environmental stresses. RNA-binding proteins （RBPs） play crucial roles in the post- transcriptional regulation via mRNA splicing, polyadenylation, sequence editing, transport, mRNA stability, mRNA localization, and translation. In this paper, four cDNAs of glycine-rich RNA-binding proteins （GR-RBPs）, named NtRGP-la, -lb, -2, and -3, were isolated from Nicotiana tabacum by RT-PCR analysis, and special emphases were given to the sequences alignment, phylogenetic analysis and gene expression. Sequences alignment revealed minor difference of cDNA sequences, but no difference of deduced proteins between N. sylvestris and N. tabacum. Phylogenetic alignment revealed that four cDNAs in tobacco were clustered into two different groups. NtRGP-2 and -3 were evolutionarily closest to Arabidopsis GR-RBPs genes and related to animal GR-RBPs genes, while NtRGP-la and -lb were closest to Gramineae GR-RBPs genes. The expression analyses of these four NtRGPs in response to different abiotic stresses revealed the similar expression pattern. Moreover, the four NtRGPs, especially NtRGP-la and NtRGP-3, were strongly induced by stresses including water, wound, cold, and high temperature, weakly induced by PEG, drought and SA, while reduced by NaC1 and unaffected by ABA treatment. The fact that all of these abiotic stresses included in our experiments affected the water balance and resulted in osmotic stress on cellular level, suggests that NtRGPs in tobacco should be a family of crucial osmosis-related proteins, and may play a key role in signal transduction with ABA-independent pathway under abiotic stresses.

Genes for RNA-binding proteins involved in neuralspecific functions and diseases are downregulated in Rubinstein-Taybi iNeurons

Taking advantage of the fast-growing knowledge of RNA-binding proteins(RBPs)we review the signature of downregulated genes for RBPs in the transcriptome of induced pluripotent stem cell neurons(iNeurons)modelling the neurodevelopmental Rubinstein Taybi Syndrome(RSTS)caused by mutations in the genes encoding CBP/p300 acetyltransferases.We discuss top and functionally connected downregulated genes sorted to“RNA processing”and“Ribonucleoprotein complex biogenesis”Gene Ontology clusters.The first set of downregulated RBPs includes members of hnRNHP(A1,A2B1,D,G,H2-H1,MAGOHB,PAPBC),core subunits of U small nuclear ribonucleoproteins and Serine-Arginine splicing regulators families,acting in precursor messenger RNA alternative splicing and processing.Consistent with literature findings on reduced transcript levels of serine/arginine repetitive matrix 4(SRRM4)protein,the main regulator of the neural-specific microexons splicing program upon depletion of Ep300 and Crebbp in mouse neurons,RSTS iNeurons show downregulated genes for proteins impacting this network.We link downregulated genes to neurological disorders including the new HNRNPH1-related intellectual disability syndrome with clinical overlap to RSTS.The set of downregulated genes for Ribosome biogenesis includes several components of ribosomal subunits and nucleolar proteins,such NOP58 and fibrillarin that form complexes with snoRNAs with a central role in guiding post-transcriptional modifications needed for rRNA maturation.These nucleolar proteins are“dual”players as fibrillarin is also required for epigenetic regulation of ribosomal genes and conversely NOP58-associated snoRNA levels are under the control of NOP58 interactor BMAL1,a transcriptional regulator of the circadian rhythm.Additional downregulated genes for“dual specificity”RBPs such as RUVBL1 and METTL1 highlight the links between chromatin and the RBP-ome and the contribution of perturbations in their cross-talk to RSTS.We underline the hub position of CBP/p300 in chromatin regulation,the impact of its defect on neurons’post-transcriptional regulation of gene expression and the potential use of epidrugs in therapeutics of RBP-caused neurodevelopmental disorders.

Involvement of XZFP36L1,an RNA-binding protein,in Xenopus neural development

Xenopus ZFP36L1(zinc finger protein 36,C3H type-like 1)belongs to the ZFP36 family of RNA-binding proteins,which contains two characteristic tandem CCCH-type zinc-finger domains.The ZFP36 proteins can bind AU-rich elements in 3'untranslated regions of target mRNAs and promote their turnover.However,the expression and role of ZFP36 genes during neural development in Xenopus embryos remains largely unknown.The present study showed that Xenopus ZFP36L1 was expressed at the dorsal part of the forebrain,forebrain-midbrain boundary,and midbrain-hindbrain boundary from late neurula stages to tadpole stages of embryonic development.Overexpression of XZFP36L1 in Xenopus embryos inhibited neural induction and differentiation,leading to severe neural tube defects.The function of XZP36L1 requires both its zinc finger and C terminal domains,which also affect its subcellular localization.These results suggest that XZFP36L1 is likely involved in neural development in Xenopus and might play an important role in post-transcriptional regulation.

Involvement of XZFP36L1, an RNA-binding protein, in Xenopus neural development ＇

Xenopus ZFP36L1 （zinc finger protein 36, C3H type-like 1） belongs to the ZFP36 family of RNA-binding proteins, which contains two characteristic tandem CCCH-type zinc-finger domains. The ZFP36 proteins can bind AU-rich elements in 3＇ untranslated regions of target mRNAs and promote their turnover. However, the expression and role of ZFP36 genes during neural development in Xenopus embryos remains largely unknown. The present study showed that Xenopus ZFP36L1 was expressed at the dorsal part of the forebrain, forebrain-midbrain boundary, and midbrain-hindbrain boundary from late neurula stages to tadpole stages of embryonic development. Overexpression of XZFP36L1 in Xenopus embryos inhibited neural induction and differentiation, leading to severe neural tube defects. The function of XZP36L1 requires both its zinc finger and C terminal domains, which also affect its subcellular localization. These results suggest that XZFP36L1 is likely involved in neural development in Xenopus and might play an important role in post-transcriptional regulation.

RNA-binding proteins related to stress response and differentiation in protozoa

RNA-binding proteins(RBPs) are key regulators of gene expression. There are several distinct families of RBPs and they are involved in the cellular response to environmental changes, cell differentiation and cell death. The RBPs can differentially combine with RNA molecules and form ribonucleoprotein(RNP) complexes, defining the function and fate of RNA molecules in the cell. RBPs display diverse domains that allow them to be categorized into distinct families. They play important roles in the cellular response to physiological stress, in cell differentiation, and, it is believed, in the cellular localization of certain mRNAs. In several protozoa, a physiological stress(nutritional, temperature or pH) triggers differentiation to a distinct developmental stage. Most of the RBPs characterized in protozoa arise from trypanosomatids. In these protozoa gene expression regulation is mostly post-transcriptional, which suggests that some RBPs might display regulatory functions distinct from those described for other eukaryotes. mRNA stability can be altered as a response to stress. Transcripts are sequestered to RNA granules that ultimately modulate their availability to the translation machinery, storage or degradation, depending on the associated proteins. These aggregates of mRNPs containing mRNAs that are not being translated colocalize in cytoplasmic foci, and their numbers and size vary according to cell conditions such as oxidative stress, nutritional status and treatment with drugs that inhibit translation.

Plant RNA-binding proteins:Phase separation dynamics and functional mechanisms underlying plant development and stress responses

RNA-binding proteins(RBPs)accompany RNA from synthesis to decay,mediating every aspect of RNA metabolism and impacting diverse cellular and developmental processes in eukaryotes.Many RBPs undergo phase separation along with their bound RNA to form and function in dynamic membraneless biomolecular condensates for spatiotemporal coordination or regulation of RNA metabolism.Increasing evidence suggests that phase-separating RBPs with RNA-binding domains and intrinsically disordered regions play important roles in plant development and stress adaptation.Here,we summarize the current knowledge about how dynamic partitioning of RBPs into condensates controls plant development and enables sensing of experimental changes to confer growth plasticity under stress conditions,with a focus on the dynamics and functional mechanisms of RBP-rich nuclear condensates and cytoplasmic granules in mediating RNA metabolism.We also discuss roles of multiple factors,such as environmental signals,protein modifications,and N6-methyladenosine RNA methylation,in modulating the phase separation behaviors of RBPs,and highlight the prospects and challenges for future research on phase-separating RBPs in crops.

Interplay of RNA-binding proteins controls germ cell development in zebrafish

The specification of germ cells in zebrafish mostly relies on an inherited mechanism by which localized maternal determinants,called germ plasm,confer germline fate in the early embryo.Extensive studies have partially allowed the identification of key regulators governing germ plasm formation and subsequent germ cell development.RNA-binding proteins,acting in concert with other germ plasm components,play essential roles in the organization of the germ plasm and the specification,migration,maintenance,and differentiation of primordial germ cells.The loss of their functions impairs germ cell formation and causes sterility or sexual conversion.Evidence is emerging that they instruct germline development through differential regulation of mRNA fates in somatic and germ cells.However,the challenge remains to decipher the complex interplay of maternal germ plasm components in germ plasm compartmentalization and germ cell specification.Because failure to control the developmental outcome of germ cells disrupts the formation of gametes,it is important to gain a complete picture of regulatory mechanisms operating in the germ cell lineage.This review sheds light on the contributions of RNA-binding proteins to germ cell development in zebrafish and highlights intriguing questions that remain open for future investigation.

Genetic variation of circHIBADH enhances prostate cancer risk through regulating HNRNPA1-related RNA splicing

The current study aimed to investigate associations of circRNAs and related genetic variants with the risk of prostate cancer(PCa)as well as to elucidate biological mechanisms underlying the associations.We first compared expression levels of circRNAs between 25 paired PCa and adjacent normal tissues to identify riskassociated circRNAs by using the MiOncoCirc database.We then used logistic regression models to evaluate associations between genetic variants in candidate circRNAs and PCa risk among 4662 prostate cancer patients and 3114 healthy controls,and identified circHIBADH rs11973492 T>C as a significant risk-associated variant(odds ratio=1.20,95%confidence interval:1.08-1.34,P=7.06×10^(-4))in a dominant genetic model,which altered the secondary structure of the corresponding RNA chain.In the in silico analysis,we found that circHIBADH sponged and silenced 21 RNA-binding proteins(RBPs)enriched in the RNA splicing pathway,among which HNRNPA1 was identified and validated as a hub RBP using an external RNA-sequencing data as well as the in-house(four tissue samples)and publicly available single-cell transcriptomes.Additionally,we demonstrated that HNRNPA1 influenced hallmarks including MYC target,DNA repair,and E2F target signaling pathways,thereby promoting carcinogenesis.In conclusion,genetic variants in circHIBADH may act as sponges and inhibitors of RNA splicing-associated RBPs including HNRNPA1,playing an oncogenic role in PCa.

RNA 结合蛋白Roquin负调控STING依赖的果蝇天然免疫反应

果蝇(Drosophila melanogaster)利用天然免疫反应来抵御外源病原菌的入侵,其分子调控机理在进化上非常保守,深入探究果蝇天然免疫调控机制对于人类天然免疫及相关疾病研究具有重要意义。为了发掘参与调控果蝇STING信号依赖的天然免疫反应的新因子,本研究采用双链RNA介导的基因表达沉默技术和双荧光素酶报告系统,在体外S2细胞中对echinus(CG2904)、usp16(CG4165)、smurf(CG4943)、pellino(CG5212)、usp47(CG5486)、diap2(CG8293)、dtraf2(CG10961)、roquin(CG16807)和usp10(CG32479)共9个编码泛素连接酶的基因进行双链RNA敲低实验,结果显示CG16807(roquin)与STING天然免疫信号水平呈现负相关。进一步通过过量表达的方法在S2细胞中过表达roquin能显著抑制STING天然免疫信号。同时,通过李斯特菌感染实验表明,敲低roquin显著提高果蝇感染后抗菌肽的表达,并抑制病原菌的增殖,从而提高果蝇感染后的存活率。本研究证明RNA结合蛋白Roquin是STING依赖的果蝇天然免疫反应的负调控因子,由于果蝇基因和人类基因存在高度相关性,因此本研究为进一步开发人类STING相关的天然免疫疾病治疗方法提供了理论基础。

RNA binding protein BOULE forms aggregates in mammalian testis

Amyloids have traditionally been considered pathologic protein aggregates which contribute to neurodegeneration.New evidence however increasingly suggests that non-pathological amyloids are formed in animals during normal development.Amyloid-like aggregate formation was originally thought to be a conserved feature of animal gametogenesis.This hypothesis was based on findings which suggest that regulated amyloid formations govern yeast meiosis by way of meiosis-specific RNA binding proteins.Additional support came from studies which demonstrate that DAZL,a mammalian gametogenesis-specific RNA binding protein,also forms SDS-resistant aggregates in vivo.Here,we report evidence of aggregated BOULE formations,another DAZ family protein,during sperm development.Data suggest that in mouse testis,BOULE forms SDS-resistant amyloid-like aggregates.BOULE aggregate formation correlates with dynamic developmental expression during spermatogenesis but disappeared in Boule knockout testis.We also mapped essential small region in vitro BOULE aggregations,immediately downstream DAZ repeats,and found that aggregations positively correlated with temperature.We also performed enhanced UV cross-linking immunoprecipitation on BOULE aggregates from mouse testes and found that aggregates bind with a large number of spermatogenesis-related mRNAs.These findings provide insight into the amyloidogenic properties of gametogenesis-specific RNA binding proteins as a conserved feature in mammalian reproduction.Further investigation is warranted to understand the functional significance of BOULE amyloid-like formation during mouse spermatogenesis.

Molecular Cloning, Expression Pattern, and 3D Structural Prediction of the Cold Inducible RNA- Binding Protein(CIRP) in Japanese Flounder(Paralichthys olivaceus)

Cold-inducible RNA-binding protein(CIRP) is a kind of RNA binding proteins that plays important roles in many physiological processes. The CIRP has been widely studied in mammals and amphibians since it was first cloned from mammals. On the contrary, there are little reports in teleosts. In this study, the Po CIRP gene of the Japanese flounder was cloned and sequenced. The genomic sequence consists of seven exons and six introns. The putative Po CIRP protein of flounder was 198 amino acid residues long containing the RNA recognition motif(RRM). Phylogenetic analysis showed that the flounder Po CIRP is highly conserved with other teleost CIRPs. The 5' flanking sequence was cloned by genome walking and many transcription factor binding sites were identified. There is a Cp Gs region located in promoter and exon I region and the methylation state is low. Quantitative real-time PCR analysis uncovered that Po CIRP gene was widely expressed in adult tissues with the highest expression level in the ovary. The m RNA of the Po CIRP was maternally deposited and the expression level of the gene was regulated up during the gastrula and neurula stages. In order to gain the information how the protein interacts with m RNA, we performed the modeling of the 3D structure of the flounder Po CIRP. The results showed a cleft existing the surface of the molecular. Taken together, the results indicate that the CIRP is a multifunctional molecular in teleosts and the findings about the structure provide valuable information for understanding the basis of this protein's function.

Regulation of RNA binding proteins in trypanosomatid protozoan parasites

Posttranscriptional mechanisms have a critical role in the overall outcome of gene expression. These mechanisms are especially relevant in protozoa from the genus Trypanosoma, which is composed by death threatening parasites affecting people in Sub-saharan Africa or in the Americas. In these parasites the classic view of regulation of transcription initiation to modulate the products of a given gene cannot be applied. This is due to the presence of transcription start sites that give rise to long polycistronic units that need to be processed costranscriptionally by trans-splicing and polyadenylation to give mature monocistronic mRNAs. Posttranscriptional mechanisms such as mRNA degradation and translational repression are responsible for the final synthesis of the required protein products. In this context, RNA-binding proteins(RBPs) in trypanosomes have a relevant role as modulators of mRNA abundance and translational repression by associating to the 3' untranslated regions in mRNA. Many different RBPs have been proposed to modulate cohorts of mRNAs in trypanosomes. However, the current understanding of their functions lacks a dynamic view on the different steps at which these RBPs are regulated. Here, we discuss different evidences to propose regulatory events for different RBPs in these parasites. These events vary from regulated developmental expression, to biogenesis of cytoplasmic ribonucleoprotein complexes in the nucleus, and condensation of RBPs and mRNA into large cytoplasmic granules. Finally, we discuss how newly identified posttranslational modifications of RBPs and mRNA metabolism-related proteins could have an enormous impact on the modulation of m RNA abundance. To understand these modifications is especially relevant in these parasites due to the fact that the enzymes involved could be interesting targets for drug therapy.

New insights into the interplay between long non-coding RNAs and RNA-binding proteins in cancer

With the development of proteomics and epigenetics,a large number of RNA-binding proteins(RBPs)have been discovered in recent years,and the inter-action between long non-coding RNAs(lncRNAs)and RBPs has also received increasing attention.It is extremely important to conduct in-depth research on the lncRNA-RBP interaction network,especially in the context of its role in the occurrence and development of cancer.Increasing evidence has demonstrated that lncRNA-RBP interactions play a vital role in cancer progression;there-fore,targeting these interactions could provide new insights for cancer drug discovery.In this review,we discussed how lncRNAs can interact with RBPs to regulate their localization,modification,stability,and activity and discussed the effects of RBPs on the stability,transport,transcription,and localization of lncRNAs.Moreover,we explored the regulation and influence of these inter-actions on lncRNAs,RBPs,and downstream pathways that are related to can-cer development,such as N6-methyladenosine(m6A)modification of lncRNAs.In addition,we discussed how the lncRNA-RBP interaction network regulates cancer cell phenotypes,such as proliferation,apoptosis,metastasis,drug resis-tance,immunity,tumor environment,and metabolism.Furthermore,we sum-marized the therapeutic strategies that target the lncRNA-RBP interaction net-work.Although these treatments are still in the experimental stage and various theories and processes are still being studied,we believe that these strategiesmay provide new ideas for cancer treatment.

Auto-regulatory feedback by RNA-binding proteins

RNA-binding proteins(RBPs)are key regulators in post-transcriptional control of gene expression.Mutations that alter their activity or abundance have been implicated in numerous diseases such as neurodegenerative disorders and various types of cancer.This highlights the importance of RBP proteostasis and the necessity to tightly control the expression levels and activities of RBPs.In many cases,RBPs engage in an auto-regulatory feedback by directly binding to and influencing the fate oftheirown mRNAs,exerting control over their own expression.For this feedback control,RBPs employ a variety of mechanisms operating at all levels of posttranscriptional regulation of gene expression.Here we review RBP-mediated autogenous feedback regulation that either serves to maintain protein abundance within a physiological range(by negative feedback)or generates binary,genetic on/off switches important for e.g.cell fate decisions(by positive feedback).

Dek42 encodes an RNA-binding protein that affects alternative pre-m RNA splicing and maize kernel development

RNA-binding proteins (RBPs) play an important role in post-transcriptional gene regulation. However, the functions of RBPs in plants remain poorly understood. Maize kernel mutant dek42 has small defective kernels and lethal seedlings. Dek42 was cloned by Mutator tag isolation and further confirmed by an independent mutant allele and clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 materials. Dek42 encodes an RRM_RBM48 type RNA-binding protein that localizes to the nucleus. Dek42 is constitutively expressed in various maize tissues. The dek42 mutation caused a significant reduction in the accumulation of DEK42 protein in mutant kernels. RNA-seq analysis showed that the dek42 mutation significantly disturbed the expression of thousands of genes during maize kernel development. Sequence analysis also showed that the dek42 mutation significantly changed alternative splicing in expressed genes, which were especially enriched for the U12-type intron-retained type. Yeast two-hybrid screening identified SF3a1 as a DEK42-interacting protein. DEK42 also interacts with the spliceosome component U1-70K. These results suggested that DEK42 participates in the regulation of pre-messenger RNA splicing through its interaction with other spliceosome components. This study showed the function of a newly identified RBP and provided insights into alternative splicing regulation during maize kernel development.