169. THE MECHANISM OF SPERMATID MATURATION - A LINK TO TUMOUR SUPPRESSION

2010 ◽  
Vol 22 (9) ◽  
pp. 87
Author(s):  
D. Jamsai ◽  
S. J. Smith ◽  
A. E. O'Connor ◽  
D. J. Merriner ◽  
C. Borg ◽  
...  
Keyword(s):  
Rna Splicing ◽  
Male Fertility ◽  
Rna Binding ◽  
Ex Vivo ◽  
Round Spermatid ◽  
Null Alleles ◽  
Compound Heterozygous ◽  
Binding Motif ◽  
Rna Recognition Motif

To comprehensively uncover novel male fertility regulators, we utilised an unbiased forward genetic screen, ENU mutagenesis. Using this approach, we have identified several novel infertile mouse lines including a male-specific infertile line that we designated ‘Joey’. The mutant Joey mice produced no sperm due to an arrest of male germ cells at the round spermatid stage. The mutation was identified in the RNA binding motif 5 (Rbm5) gene that resulted in an arginine to proline substitution within a highly conserved RNA recognition motif of the protein. The substitution of proline is likely to interfere with RNA binding and/or recognition. In humans, the RBM5 gene maps to a region that is frequently deleted in lung cancers. Ex vivo studies have suggested that RBM5 is a tumour suppressor, apoptosis modulator and RNA splicing regulator. To date, the role of Rbm5 has never been liked to male fertility and the Joey line is the only mouse model of Rbm5 dysfunction. Using our RBM5-specific antibody, we showed that RBM5 is expressed in pachytene spermatocytes and round spermatids. Based on the protein localisation, the proposed role of RBM5 in mRNA processing, the onset of the Joey phenotype, and the site of the identified mutation, we hypothesise that the Rbm5 mutant allele results in a hypomorphic protein, and that RBM5 has an essential role in regulating male germ cell mRNA storage, transport and/or translational regulation of mRNAs that are critical for spermatid maturation. Further, we generated mice compound heterozygous of the Joey Rbm5 mutation and Rbm5 null alleles. We showed that the compound heterozygous males are infertile due to spermatid maturation arrest resembling the Joey mutant males. This result further confirmed the identification of the Rbm5 mutation as a cause of infertility in the Joey mice and a crucial role of Rbm5 in male fertility.

Structure of the mRNA splicing complex component Cwc2: insights into RNA recognition

2011 ◽  
Vol 441 (2) ◽  
pp. 591-597 ◽  
Author(s):  
Peilong Lu ◽  
Guifeng Lu ◽  
Chuangye Yan ◽  
Li Wang ◽  
Wenqi Li ◽  
...  
Keyword(s):  
Rna Splicing ◽  
Rna Binding ◽  
Mutational Analysis ◽  
Hydrophobic Interactions ◽  
Mrna Splicing ◽  
Regulatory Function ◽  
Rna Recognition Motif ◽  
Rna Recognition ◽  
Core Domain ◽  
Intron Removal

The Prp19-associated complex [NTC (nineteen complex)] plays a crucial role in intron removal during premature mRNA splicing in eukaryotes. Only one component of the NTC, Cwc2, is capable of binding RNA. In the present study we report the 1.9 Å (1 Å=0.1 nm) X-ray structure of the Cwc2 core domain, which is both necessary and sufficient for RNA binding. The Cwc2 core domain contains two sub-domains, a CCCH-type ZnF (zinc finger) and a RRM (RNA recognition motif). Unexpectedly, the ZnF domain and the RRM form a single folding unit, glued together by extensive hydrophobic interactions and hydrogen bonds. Structure-guided mutational analysis revealed that the intervening loop [known as the RB loop (RNA-binding loop)] between ZnF and RRM plays an essential role in RNA binding. In addition, a number of highly conserved positively charged residues on the β-strands of RRM make an important contribution to RNA binding. Intriguingly, these residues and a portion of the RB loop constitute an extended basic surface strip that encircles Cwc2 halfway. The present study serves as a framework for understanding the regulatory function of the NTC in RNA splicing.

scholarly journals The Antiviral and Cancer Genomic DNA Deaminase APOBEC3H Is Regulated by a RNA-Mediated Dimerization Mechanism

2017 ◽  
Author(s):  
Nadine M. Shaban ◽  
Ke Shi ◽  
Kate V. Lauer ◽  
Michael A. Carpenter ◽  
Christopher M. Richards ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Rna Binding ◽  
Cytosine Deaminase ◽  
Rnase A ◽  
Binding Motif ◽  
Innate And Adaptive Immunity ◽  
Enzyme Preparations ◽  
Gene Diversification ◽  
Hiv 1

SUMMARYHuman APOBEC3H and homologous single-stranded DNA cytosine deaminases are unique to mammals. These DNA editing enzymes function in innate immunity by restricting the replication of viruses and transposons. Misregulated APOBEC3H also contributes to cancer mutagenesis. Here we address the role of RNA in APOBEC3H regulation. APOBEC3H co-purifies with RNA as an inactive protein, and RNase A treatment yields enzyme preparations with stronger DNA deaminase activity. RNA binding-defective mutants are DNA hypermutators. Chromatography profiles and crystallographic data demonstrate a mechanism in which double-stranded RNA mediates enzyme dimerization. RNA binding is required for APOBEC3H cytoplasmic localization and for packaging into HIV-1 particles and antiviral activity. Related DNA deaminases including other APOBEC3 family members and the antibody gene diversification enzyme AID also bind RNA and are predicted to have a similar RNA binding motif suggesting mechanistic conservation and relevance to innate and adaptive immunity and to multiple diseases.HIGHLIGHTSRNA inhibits human APOBEC3H DNA cytosine deaminase activityRNA binding mutants are DNA hypermutatorsX-ray structure demonstrates an RNA duplex-mediated APOBEC3H dimerization mechanismRNA binding is required for packaging into HIV-1 particles and antiviral activity

scholarly journals The Spliceosome As a New Therapeutic Target in Cytarabine-Resistant Acute Myeloid Leukemia

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3334-3334
Author(s):  
María Luz Morales ◽  
Roberto Garcia-Vicente ◽  
Alba Rodríguez García ◽  
Noemí Álvarez Sánchez-Redondo ◽  
Alejandra Ortiz-Ruiz ◽  
...  
Keyword(s):  
Gene Expression ◽  
Board Of Directors ◽  
Rna Splicing ◽  
Ex Vivo ◽  
Sr Proteins ◽  
Splicing Factors ◽  
Advisory Committees ◽  
Paired Samples

Abstract Introduction. Despite the recent approval of several drugs for the treatment of AML, the 3 + 7 regimens remain as the standard of care for many patients. Its lack of efficacy represents the main cause of death, since only 10% of patients who show refractoriness/relapse overcome the disease. Therefore, there is still an urgent need for seeking more effective treatments. Aberrant RNA splicing has been described in AML, but its relevance as mechanism of resistance is unclear. In this study, we deepen the mechanism of resistance to cytarabine and the role of splicing factors SR proteins, involved in the spliceosome functionality, to seek more effective therapies for AML. Methods. First, the expression levels of genes encoding SR proteins were analyzed with the GEPIA2 platform, comparing the data from the TCGA-LAML (AML patients) and GTEx (healthy) projects. Then, the gene expression of one of the most overexpressed genes, SRRM2, was validated by qPCR in samples of AML patients compared to controls and other myeloid disorders, as MDS and MPN (n=54). The resistance-associated phospho-proteomic profile was analyzed by LC-MS / MS after IMAC enrichment in paired samples from 3 AML patients. The expression of SR proteins and their phosphorylated forms was studied by immunohistochemistry (IHC) before and after resistance in paired bone marrow samples from 3 AML patients. We also analyzed by IHC the prognostic value of phospho-SR proteins at the moment of diagnosis in 64 patients with different responses to cytarabine (non-responders and responders). In order to validate an altered function of SR proteins, the analysis of the differential use of exons of paired samples from 25 AML patients was performed using RNAseq. Then, we evaluated in vitro the efficacy of some splicing modulators, and its combination with other approved drugs, in cytarabine-sensitive and resistant cells. The combination of H3B-8800, a spliceosome inhibitor, with venetoclax was tested in ex vivo samples from AML patients and healthy donors. Results. We found that the gene expression levels of SRSF9, SRSF12 and SRRM2 were altered in AML (Fig 1A-B). Immunohistochemical studies revealed that, although at the protein level no differences were found in SR proteins expression between the diagnosis and relapse moment, an increase in the levels of phosphorylated SR proteins was associated at the time of relapse (Fig 1C). Indeed, the phosphorylation levels of SRRM2, among other SR proteins, were found to be increased during cytarabine resistance by phospho-proteomics (Fig 1D). Moreover, the phosphorylation levels of SR proteins predicted the response to cytarabine treatment, as AML patients that were non-responders presented significantly higher levels compared to responders ones (Fig 1E). The observed alterations in the phosphorylation of these proteins were correlated with a differential use of exons in some of their known targets, when comparing the diagnostic condition and drug resistance moment. Based on this evidence, the efficacy of combining different therapeutic options was evaluated in vitro using sensitive or cytarabine-resistant cell models (Fig 1F). The combination of H3B-8800 together with venetoclax was the most effective in vitro and also presented synergic effects ex vivo in AML patients samples (Fig 1G). Furthermore, this combination did not show toxicity over healthy hematopoietic progenitors, since the same doses that were effective in AML did not show toxicity in a healthy context (Fig 1H). Conclusions. The results of this work shed light on the role of the RNA splicing process in cytarabine resistance in AML. Interestingly, the high levels of phosphorylated splicing factors SR proteins at diagnosis in refractory patients, would allow us to use them as a predictive biomarker of response to cytarabine treatment. Otherwise, due to the need to search effective and safe treatments in this disease, we have found that the combination of splicing inhibitors with venetoclax should be a good strategy for the treatment of AML. Acknowledgment. This work has been possible thanks to the granting of the project PI19/01518 from the Carlos III Health Institute and the CRIS Against Cancer Foundation. ML.M. enjoys a research grant from the Spanish Society of Hematology and Hemotherapy and R.GV. a FPU grant from the Ministry of Science, Innovation and Universities. Figure 1 Figure 1. Disclosures Sanchez: Altum sequencing: Current Employment. Ayala: Incyte Corporation: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astellas: Honoraria; Celgene: Honoraria.

scholarly journals NF90/ILF3 is a transcription factor that promotes proliferation over differentiation by hierarchical regulation in K562 erythroleukemia cells

2017 ◽  
Author(s):  
Ting-Hsuan Wu ◽  
Lingfang Shi ◽  
Jessika Adrian ◽  
Minyi Shi ◽  
Ramesh V. Nair ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Rna Splicing ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
K562 Cells ◽  
Dna And Rna ◽  
Erythroleukemia Cells ◽  
Binding Factor ◽  
Differential Gene

ABSTRACTNF90 and splice variant NF110 are DNA‐ and RNA-binding proteins encoded by the Interleukin enhancer-binding factor 3 (ILF3) gene that regulate RNA splicing, stabilization and export. The role of NF90 in regulating transcription as a DNA-binding protein has not been comprehensively characterized. Here, ENCODE ChIP-seq identified 9,081 genomic sites specifically bound by NF90/110 in K562 cells. One third of binding sites occurred at promoters of annotated genes. NF90/110 binding colocalized with chromatin marks associated with active promoters and strong enhancers. Comparison with 150 ENCODE ChIP-seq experiments revealed that NF90 clustered with transcription factors exhibiting preference for promoters over enhancers (POLR2A, MYC, YY1). Differential gene expression analysis following shRNA knockdown of NF90 in K562 cells revealed that NF90 directly activates transcription factors that drive growth and proliferation (EGR1, MYC), while attenuating differentiation along erythroid lineage (KLF1). NF90/110 binds chromatin to hierarchically regulate transcription factors to promote proliferation and suppress differentiation.

scholarly journals Cyp33 Binds AU-Rich RNA Motifs via an Extended Interface that Competitively Disrupts the Gene Repressive Cyp33-MLL1 Interaction in vitro

2020 ◽  
Author(s):  
Neil R. Lloyd ◽  
Deborah S. Wuttke
Keyword(s):  
Chromatin Remodeling ◽  
Rna Binding ◽  
Gene Activation ◽  
Direct Interaction ◽  
Rna Aptamers ◽  
Binding Motif ◽  
Rna Recognition Motif ◽  
Isomerase Activity ◽  
Rrm Domain

AbstractCyp33 is an essential human cyclophilin prolyl isomerase that plays myriad roles in splicing and chromatin remodeling. In addition to a canonical cyclophilin (Cyp) domain, Cyp33 contains an RNA-recognition motif (RRM) domain, and RNA-binding triggers proline isomerase activity. One prominent role for Cyp33 is through a direct interaction with the mixed lineage leukemia protein 1 (MLL1, also known as KMT2A) complex, which is a histone methyltransferase that serves as a global regulator of human transcription. MLL activity is regulated by Cyp33, which isomerizes a key proline in the linker between the PHD3 and Bromo domains of MLL1, acting as a switch between gene activation and repression. The direct interaction between MLL1 and Cyp33 is critical, as deletion of the MLL1-PHD3 domain responsible for this interaction results in oncogenesis. The Cyp33 RRM is central to these activities, as it binds both the PHD3 domain and RNA. To better understand how RNA binding drives the action of Cyp33, we performed RNA-SELEX against full-length Cyp33 accompanied by deep sequencing. We have identified an enriched Cyp33 binding motif (AAUAAUAA) broadly represented in the cellular RNA pool as well as tightly binding RNA aptamers with affinities comparable and competitive with the Cyp33 MLL1-PHD3 interaction. RNA binding extends beyond the canonical RRM domain, but not to the Cyp domain, suggesting an indirect mechanism of interaction. NMR chemical shift mapping confirms an overlapping, but not identical, interface on Cyp33 for RNA and PHD3 binding. This finding suggests RNA can disrupt the gene repressive Cyp33-MLL1 complex providing another layer of regulation for chromatin remodeling by MLL1.

scholarly journals Role of Viral Ribonucleoproteins in Human Papillomavirus Type 16 Gene Expression

Viruses ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1110 ◽  
Author(s):  
Naoko Kajitani ◽  
Stefan Schwartz
Keyword(s):  
Gene Expression ◽  
Rna Processing ◽  
Rna Splicing ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Human Papillomaviruses ◽  
Protein Coding ◽  
Human Papillomavirus Type 16 ◽  
Definition Of

Human papillomaviruses (HPVs) depend on the cellular RNA-processing machineries including alternative RNA splicing and polyadenylation to coordinate HPV gene expression. HPV RNA processing is controlled by cis-regulatory RNA elements and trans-regulatory factors since the HPV splice sites are suboptimal. The definition of HPV exons and introns may differ between individual HPV mRNA species and is complicated by the fact that many HPV protein-coding sequences overlap. The formation of HPV ribonucleoproteins consisting of HPV pre-mRNAs and multiple cellular RNA-binding proteins may result in the different outcomes of HPV gene expression, which contributes to the HPV life cycle progression and HPV-associated cancer development. In this review, we summarize the regulation of HPV16 gene expression at the level of RNA processing with focus on the interactions between HPV16 pre-mRNAs and cellular RNA-binding factors.

scholarly journals LncRNA MM2P-induced, exosome-mediated transfer of Sox9 from monocyte-derived cells modulates primary chondrocytes

2020 ◽  
Vol 11 (9) ◽  
Author(s):  
Jinyu Bai ◽  
Yingzi Zhang ◽  
Xin Zheng ◽  
Man Huang ◽  
Weinan Cheng ◽  
...  
Keyword(s):  
Rna Binding ◽  
Ex Vivo ◽  
Type Ii Collagen ◽  
Mouse Bone Marrow ◽  
Primary Chondrocytes ◽  
Non Coding Rna ◽  
Transmission Electron ◽  
Extracellular Matrix Components ◽  
Long Non Coding Rna

Abstract Monocyte-derived cells were shown to promote cartilage repair in osteoarthritis. The role of the long non-coding RNA (lncRNA) MM2P in this function of monocyte-derived cells remained unexplored. Treatment of RAW264.7 murine macrophages and mouse bone marrow-derived macrophages with IL-4 or IL-13 upregulated MM2P expression, upstream of STAT3 and STAT6 phosphorylation. Specifically, MM2P blocked SHP2-mediated dephosphorylation of STAT3 at Try705 and interacted with the RNA-binding protein FUS. In turn, p-STAT3 increased the Sox9 gene expression. These cells released Sox9 mRNA and protein-containing exosomes, as demonstrated by a transmission electron microscope, nanoparticle tracking analysis, and detection of typical surface markers. Their culture supernatant promoted the differentiation of mouse primary chondrocytes, i.e., upregulated the expression of Col1a2 and Acan genes and promoted the secretion of extracellular matrix components proteoglycan and type II collagen. These effects were mediated by Sox9 mRNA and protein delivered to chondrocytes by exosomes. Together, ex vivo treatment of monocyte-derived cells with IL-4 or IL-13 promoted chondrocyte differentiation and functions through exosome-mediated delivery of Sox9 mRNA and protein.

scholarly journals Structural basis of UCUU RNA motif recognition by splicing factor RBM20

2019 ◽  
Author(s):  
Santosh Kumar Upadhyay ◽  
Cameron D. Mackereth
Keyword(s):  
Heart Development ◽  
Rna Binding ◽  
Protein Isoforms ◽  
Splicing Factor ◽  
Common Element ◽  
Structural Basis ◽  
Binding Motif ◽  
Rna Recognition Motif ◽  
Rrm Domain ◽  
Rna Motif

ABSTRACTThe vertebrate splicing factor RBM20 (RNA Binding Motif protein 20) regulates protein isoforms important for heart development and function, with mutations in the gene linked to cardiomyopathy. Previous studies have identified the four base RNA motif UCUU as a common element in pre-mRNA targeted by RBM20. Here, we have determined the structure of the RNA Recognition Motif (RRM) domain from mouse RBM20 bound to RNA containing a UCUU sequence. The atomic details show that the RRM domain spans a larger region than initially proposed in order to interact with the complete UCUU motif, with a well-folded C-terminal helix encoded by exon 8 critical for high affinity binding. This helix only forms upon binding RNA with the final uracil, and removing the helix reduces affinity as well as specificity. We therefore find that RBM20 uses a coupled folding-binding mechanism by the C-terminal helix to specifically recognize the UCUU RNA motif.

scholarly journals Prognostic value and oncogenic effect of increased RBM8A expression in colon adenocarcinoma

2021 ◽  
Author(s):  
Zhongpeng Xie ◽  
Yu Wu ◽  
Yahui Huang ◽  
Yuxiang Cai ◽  
Yanyan Wang ◽  
...  
Keyword(s):  
Rna Binding ◽  
Colon Adenocarcinoma ◽  
Clinicopathological Characteristics ◽  
Survival Prediction ◽  
Binding Motif ◽  
Depth Of Invasion ◽  
Protein Levels

RNA Binding Motif Protein 8A (RBM8A) is a component of the spliceosome, which couples pre- and post-mRNA splicing events. Dysregulated expression of RBM8A has been recently discovered in hepatocellular carcinoma and gastric cancer. This study aimed to investigate the expression pattern of RBM8A protein in colon adenocarcinoma and to explore its correlation with patients’ clinicopathological characteristics as well as clinical outcomes. Accordingly, we initially found that RBM8A was significantly higher in colon adenocarcinoma tissues compared to adjacent tissues on both mRNA and protein levels. Meanwhile, RBM8A protein was positively correlated with tumor size, depth of invasion, and lymph node metastasis. Furthermore, patients with increased RBM8A expression or positive lymph nodes exhibited a poorer overall survival. Consistently, immunoblotting data showed that RBM8A was higher in SW480 and SW620 colon adenocarcinoma cell lines compared to nontumorous cells. Finally, in vitro and in vivo assays elucidated the role of RBM8A on promoting colon cancer growth by using knockdown strategy. Taken together, our study demonstrated that RBM8A may act as a proto-oncogene, which could be a promising biomarker and therapeutic target in the survival prediction and treatment of colon adenocarcinoma.

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