Integrated systematic functional screen and fine-mapping decipher the role and genetic regulation of RPS19 in colorectal cancer development.

Despite genome-wide association studies (GWAS) have identified more than 200 risk loci associated with colorectal cancer (CRC), the causal genes or risk variants within these loci and their biological functions remain not fully revealed. Recently, the genomic locus 19q13.2, with the lead SNP rs1800469 was identified as a crucial CRC risk locus in Asian populations. However, the functional mechanism of this region has not been fully elucidated. Here we employed an RNA interfering-based on-chip approach to screen for the genes essential for cell proliferation in the CRC risk locus 19q13.2. Notably, we found that RPS19 exhibited the most significant effect among the identified genes and acted as a critical oncogene facilitating CRC cell proliferation. Subsequently, combining integrative fine-mapping analysis and a large-scale population study consisting of 6027 cases and 6099 controls, we prioritized rs1025497 as a potential causal candidate for CRC risk, demonstrating that rs1025497[A] allele significantly reduced the risk of CRC (OR 0.70, 95% confidence interval = 0.56-0.83, P = 1.12 × 10-6), which was further validated in UK Biobank cohort comprising 5,313 cases and 21,252 controls. Mechanistically, we experimentally elucidated that variant rs1025497 might acted as an allele-specific silencer, inhibiting the expression level of oncogene RPS19 mediated by the transcription suppressive factor HBP1. Taken together, our sturdy unveils the significant role of RPS19 during CRC pathogenesis and delineates its distal regulatory mechanism mediated by rs1025497, advancing our understanding of the etiology of CRC and provided new insights into the personalized medicine of human cancer.

Daptomycin Inhibits Multiple Myeloma Progression through Downregulating the Expression of RPS19.

OBJECTIVES: This study aimed to explore new therapeutic drugs for multiple myeloma (MM). MM is a common plasma cell malignant proliferative disease, accounting for 15% of hematological malignancies. The role of daptomycin (DAP), a potential anti-tumor drug, remains unclear in MM. In the present research, we investigated the anticancer effect of DAP in MM cell line RPMI 8226. METHODS: RPMI 8226 cells were treated with DAP (20 µM, 40 µM, and 80 µM) with 20 nM bortezomib (BZ) as a positive control. Cell function was detected using CCK8, flow cytometry, and transwell assay. RESULTS: In MM cells, DAP inhibited proliferation and induced apoptosis. The cell cycle was arrested at the G1 phase after the treatment of DAP. The migration and invasion abilities were also inhibited by DAP treatment in RPMI 8226 cells. Importantly, the mRNA and protein levels of RPS19 were downregulated in DAP-treated RPMI 8226 cells. CONCLUSION: DAP inhibited the proliferation, migration, and invasion and promoted the apoptosis of MM cells. Mechanistically, the RPS19 expression was significantly decreased in DAPtreated cells. This research provides a potential therapeutic drug for MM therapy.

Probable digenic inheritance of Diamond-Blackfan anemia.

A 26-year-old female proband with a clinical diagnosis and consistent phenotype of Diamond-Blackfan anemia (DBA, OMIM 105650) without an identified genotype was referred to the Undiagnosed Diseases Network. DBA is classically associated with monoallelic variants that have an autosomal-dominant or -recessive mode of inheritance. Intriguingly, her case was solved by a detection of a digenic interaction between non-allelic RPS19 and RPL27 variants. This was confirmed with a machine learning structural model, co-segregation analysis, and RNA sequencing. This is the first report of DBA caused by a digenic effect of two non-allelic variants demonstrated by machine learning structural model. This case suggests that atypical phenotypic presentations of DBA may be caused by digenic inheritance in some individuals. We also conclude that a machine learning structural model can be useful in detecting digenic models of possible interactions between products encoded by alleles of different genes inherited from non-affected carrier parents that can result in DBA with an unrealized 25% recurrence risk.

Intercellular Molecular Crosstalk Networks within Invasive and Immunosuppressive Tumor Microenvironment Subtypes Associated with Clinical Outcomes in Four Cancer Types.

Heterogeneity is a critical basis for understanding how the tumor microenvironment (TME) contributes to tumor progression. However, an understanding of the specific characteristics and functions of TME subtypes (subTMEs) in the progression of cancer is required for further investigations into single-cell resolutions. Here, we analyzed single-cell RNA sequencing data of 250 clinical samples with more than 200,000 cells analyzed in each cancer datum. Based on the construction of an intercellular infiltration model and unsupervised clustering analysis, four, three, three, and four subTMEs were revealed in breast, colorectal, esophageal, and pancreatic cancer, respectively. Among the subTMEs, the immune-suppressive subTME (subTME-IS) and matrix remodeling with malignant cells subTME (subTME-MRM) were highly enriched in tumors, whereas the immune cell infiltration subTME (subTME-ICI) and precancerous state of epithelial cells subTME (subTME-PSE) were less in tumors, compared with paracancerous tissues. We detected and compared genes encoding cytokines, chemokines, cytotoxic mediators, PD1, and PD-L1. The results showed that these genes were specifically overexpressed in different cell types, and, compared with normal tissues, they were upregulated in tumor-derived cells. In addition, compared with other subTMEs, the expression levels of PDCD1 and TGFB1 were higher in subTME-IS. The Cox proportional risk regression model was further constructed to identify possible prognostic markers in each subTME across four cancer types. Cell-cell interaction analysis revealed the distinguishing features in molecular pairs among different subTMEs. Notably, ligand-receptor gene pairs, including COL1A1-SDC1, COL6A2-SDC1, COL6A3-SDC1, and COL4A1-ITGA2 between stromal and tumor cells, associated with tumor invasion phenotypes, poor patient prognoses, and tumor advanced progression, were revealed in subTME-MRM. C5AR1-RPS19, LGALS9-HAVCR2, and SPP1-PTGER4 between macrophages and CD8+ T cells, associated with CD8+ T-cell dysfunction, immunosuppressive status, and tumor advanced progression, were revealed in subTME-IS. The spatial co-location information of cellular and molecular interactions was further verified by spatial transcriptome data from colorectal cancer clinical samples. Overall, our study revealed the heterogeneity within the TME, highlighting the potential pro-invasion and pro-immunosuppressive functions and cellular infiltration characteristics of specific subTMEs, and also identified the key cellular and molecular interactions that might be associated with the survival, invasion, immune escape, and classification of cancer patients across four cancer types.

Hematopoietic cell transplantation and gene therapy for Diamond-Blackfan anemia: state of the art and science.

Diamond-Blackfan anemia (DBA) is one of the most common inherited causes of bone marrow failure in children. DBA typically presents with isolated erythroid hypoplasia and anemia in infants. Congenital anomalies are seen in 50% of the patients. Over time, many patients experience panhematopoietic defects resulting in immunodeficiency and multilineage hematopoietic cytopenias. Additionally, DBA is associated with increased risk of myelodysplastic syndrome, acute myeloid leukemia and solid organ cancers. As a prototypical ribosomopathy, DBA is caused by heterozygous loss-of-function mutations or deletions in over 20 ribosomal protein genes, with RPS19 being involved in 25% of patients. Corticosteroids are the only effective initial pharmacotherapy offered to transfusion-dependent patients aged 1 year or older. However, despite good initial response, only ~20-30% remain steroid-responsive while the majority of the remaining patients will require life-long red blood cell transfusions. Despite continuous chelation, iron overload and related toxicities pose a significant morbidity problem. Allogeneic hematopoietic cell transplantation (HCT) performed to completely replace the dysfunctional hematopoietic stem and progenitor cells is a curative option associated with potentially uncontrollable risks. Advances in HLA-typing, conditioning regimens, infection management, and graft-versus-host-disease prophylaxis have led to improved transplant outcomes in DBA patients, though survival is suboptimal for adolescents and adults with long transfusion-history and patients lacking well-matched donors. Additionally, many patients lack a suitable donor. To address this gap and to mitigate the risk of graft-versus-host disease, several groups are working towards developing autologous genetic therapies to provide another curative option for DBA patients across the whole age spectrum. In this review, we summarize the results of HCT studies and review advances and potential future directions in hematopoietic stem cell-based therapies for DBA.

LINC00106/RPS19BP1/p53 axis promotes the proliferation and migration of human prostate cancer cells.

Background: Prostate cancer (PCa) is among the most prevalent cancers in males with high biochemical recurrence risk. LINC00106 contributes to the carcinogenesis of Hepatocellular carcinoma (HCC). However, it is unclear how it affects PCa advancement. Here, we studied LINC00106's effects on PCa cells' ability to proliferate, invade, and metastasize. Methods: The data of LINC00106 from The Cancer Genome Atlas (TCGA) in human PCa tissues were analyzed using TANRIC and survival analysis. In order to determine the expression levels of genes and proteins, we also performed reverse transcription-quantitative PCR and western blot analysis. The migration, invasion, colony formation, and proliferation (CCK-8) of PCa cells with LINC00106 knockdown were investigated. The impact of LINC00106 on cell proliferation and invasion was also analyzed in mice. LncRNA prediction software catRAPID omics v2.1 (catRAPID omics v2.0 (tartaglialab.com)) was used to predict proteins that might interact with LINC00106. The interactions were verified via RNA immunoprecipitation and RNA pull-down assays and finally, the interaction between LINC00106 and its target protein and the p53 signaling pathway was studied using a dual-luciferase reporter assay. Results: In PCa, LINC00106 was over-expressed in comparison to normal tissues, and it was linked to an unfavorableprognosis. In vitro and in vivo analyses showed that downregulating LINC00106 decreased PCa cells'ability to proliferate and migrate. A common regulatory axis generated by LINC00106 and RPS19BP1 prevents p53 activity. Conclusion: Our experimental data indicate that LINC00106 functions as an oncogene in the onset of PCa, and the LINC00106/RPS19BP1/P53 axis canserve as a novel therapeutic target for PCa treatment.

Mutations in RPS19 may affect ribosome function and biogenesis in Diamond Blackfan anemia.

Ribosomes, the cellular organelles translating the genetic code to proteins, are assemblies of RNA chains and many proteins (RPs) arranged in precise fine-tuned interwoven structures. Mutated ribosomal genes cause ribosomopathies, including Diamond Blackfan anemia (DBA, a rare heterogeneous red-cell aplasia connected to ribosome malfunction) or failed biogenesis. Combined bioinformatical, structural, and predictive analyses of potential consequences of possibly expressed mutations in eS19, the protein product of the highly mutated RPS19, suggest that mutations in its exposed surface could alter its positioning during assembly and consequently prevent biogenesis, implying a natural selective strategy to avoid malfunctions in ribosome assembly. A search for RPS19 pseudogenes indicated > 90% sequence identity with the wild-type, hinting at its expression in cases of absent or truncated gene products.

Msl3 promotes germline stem cell differentiation in female Drosophila.

Gamete formation from germline stem cells (GSCs) is essential for sexual reproduction. However, the regulation of GSC differentiation is incompletely understood. Set2, which deposits H3K36me3 modifications, is required for GSC differentiation during Drosophila oogenesis. We discovered that the H3K36me3 reader Male-specific lethal 3 (Msl3) and histone acetyltransferase complex Ada2a-containing (ATAC) cooperate with Set2 to regulate GSC differentiation in female Drosophila. Msl3, acting independently of the rest of the male-specific lethal complex, promotes transcription of genes, including a germline-enriched ribosomal protein S19 paralog RpS19b. RpS19b upregulation is required for translation of RNA-binding Fox protein 1 (Rbfox1), a known meiotic cell cycle entry factor. Thus, Msl3 regulates GSC differentiation by modulating translation of a key factor that promotes transition to an oocyte fate.

Tumor-initiating stem cell shapes its microenvironment into an immunosuppressive barrier and pro-tumorigenic niche.

Tumor-initiating stem cells (TSCs) are critical for drug resistance and immune escape. However, the mutual regulations between TSC and tumor microenvironment (TME) remain unclear. Using DNA-label retaining, single-cell RNA sequencing (scRNA-seq), and other approaches, we investigated intestinal adenoma in response to chemoradiotherapy (CRT), thus identifying therapy-resistant TSCs (TrTSCs). We find bidirectional crosstalk between TSCs and TME using CellPhoneDB analysis. An intriguing finding is that TSCs shape TME into a landscape that favors TSCs for immunosuppression and propagation. Using adenoma-organoid co-cultures, niche-cell depletion, and lineaging tracing, we characterize a functional role of cyclooxygenase-2 (Cox-2)-dependent signaling, predominantly occurring between tumor-associated monocytes and macrophages (TAMMs) and TrTSCs. We show that TAMMs promote TrTSC proliferation through prostaglandin E2 (PGE2)-PTGER4(EP4) signaling, which enhances ß-catenin activity via AKT phosphorylation. Thus, our study shows that the bidirectional crosstalk between TrTSC and TME results in a pro-tumorigenic and immunosuppressive contexture.

Atovaquone Suppresses Triple-Negative Breast Tumor Growth by Reducing Immune-Suppressive Cells.

A major contributing factor in triple-negative breast cancer progression is its ability to evade immune surveillance. One mechanism for this immunosuppression is through ribosomal protein S19 (RPS19), which facilitates myeloid-derived suppressor cells (MDSCs) recruitment in tumors, which generate cytokines TGF-ß and IL-10 and induce regulatory T cells (Tregs), all of which are immunosuppressive and enhance tumor progression. Hence, enhancing the immune system in breast tumors could be a strategy for anticancer therapeutics. The present study evaluated the immune response of atovaquone, an antiprotozoal drug, in three independent breast-tumor models. Our results demonstrated that oral administration of atovaquone reduced HCC1806, CI66 and 4T1 paclitaxel-resistant (4T1-PR) breast-tumor growth by 45%, 70% and 42%, respectively. MDSCs, TGF-ß, IL-10 and Tregs of blood and tumors were analyzed from all of these in vivo models. Our results demonstrated that atovaquone treatment in mice bearing HCC1806 tumors reduced MDSCs from tumor and blood by 70% and 30%, respectively. We also observed a 25% reduction in tumor MDSCs in atovaquone-treated mice bearing CI66 and 4T1-PR tumors. In addition, a decrease in TGF-ß and IL-10 in tumor lysates was observed in atovaquone-treated mice with a reduction in tumor Tregs. Moreover, a significant reduction in the expression of RPS19 was found in tumors treated with atovaquone.

Proerythroblast Cells of Diamond-Blackfan Anemia Patients With RPS19 and CECR1 Mutations Have Similar Transcriptomic Signature.

Diamond Blackfan Anemia (DBA) is an inherited bone marrow (BM) failure syndrome, characterized by a paucity of erythroid differentiation. DBA is mainly caused by the mutations in ribosomal protein genes, hence classified as ribosomopathy. However, in approximately 30% of patients, the molecular etiology cannot be discovered. RPS19 germline mutations caused 25% of the cases. On the other hand, CECR1 mutations also cause phenotypes similar to DBA but not being a ribosomopathy. Due to the blockade of erythropoiesis in the BM, we investigated the transcriptomic profile of three different cell types of BM resident cells of DBA patients and compared them with healthy donors. From BM aspirates BM mononuclear cells (MNCs) were isolated and hematopoietic stem cells (HSC) [CD71-CD34+ CD38mo/lo], megakaryocyte-erythroid progenitor cells (MEP) [CD71-CD34+ CD38hi] and Proerythroblasts [CD71+ CD117+ CD38+] were sorted and analyzed with a transcriptomic approach. Among all these cells, proerythroblasts had the most different transcriptomic profile. The genes associated with cellular stress/immune responses were increased and some of the transcription factors that play a role in erythroid differentiation had altered expression in DBA proerythroblasts. We also showed that gene expression levels of ribosomal proteins were decreased in DBA proerythroblasts. In addition to these, colony formation assay (CFU-E) provided functional evidence of the failure of erythroid differentiation in DBA patients. According to our findings that all patients resembling both RPS19 and CECR1 mutations have common transcriptomic signatures, it may be possible that inflammatory BM niche may have a role in DBA pathogenesis.

Computational Studies of the Structural Basis of Human RPS19 Mutations Associated With Diamond-Blackfan Anemia.

Diamond-Blackfan Anemia (DBA) is an inherited rare disease characterized with severe pure red cell aplasia, and it is caused by the defective ribosome biogenesis stemming from the impairment of ribosomal proteins. Among all DBA-associated ribosomal proteins, RPS19 affects most patients and carries most DBA mutations. Revealing how these mutations lead to the impairment of RPS19 is highly demanded for understanding the pathogenesis of DBA, but a systematic study is currently lacking. In this work, based on the complex structure of human ribosome, we comprehensively studied the structural basis of DBA mutations of RPS19 by using computational methods. Main structure elements and five conserved surface patches involved in RPS19-18S rRNA interaction were identified. We further revealed that DBA mutations would destabilize RPS19 through disrupting the hydrophobic core or breaking the helix, or perturb the RPS19-18S rRNA interaction through destroying hydrogen bonds, introducing steric hindrance effect, or altering surface electrostatic property at the interface. Moreover, we trained a machine-learning model to predict the pathogenicity of all possible RPS19 mutations. Our work has laid a foundation for revealing the pathogenesis of DBA from the structural perspective.

Diamond-Blackfan anemia with mutation in RPS19: A case report and an overview of published pieces of literature.

INTRODUCTION: Diamond-Blackfan anemia (DBA), one of a rare group of inherited bone marrow failure syndromes, is characterized by red cell failure, the presence of congenital anomalies, and cancer predisposition. It can be caused by mutations in the RPS19 gene (25% of the cases). METHODS: This case report describes a 10-month-old boy who presented with 2 months' history of gradually increasing weakness and pallor. RESULTS: The patient was diagnosed as a case of DBA based on peripheral blood finding, bone marrow aspiration with trephine biopsy reports, and genetic mutation analysis of the RPS19 gene. His father refused hematopoietic stem cell transplantation for financial constraints. Patient received prednisolone therapy with oral folic acid and iron supplements. CONCLUSION: Hemoglobin raised from 6.7 to 9.8g/dL after 1 month of therapeutic intervention.

Drought Stress Tolerance and Photosynthetic Activity of Alloplasmic Lines T. dicoccum x T. aestivum.

Tetraploid species T. dicoccum Shuebl is a potential source of drought tolerance for cultivated wheat, including common wheat. This paper describes the genotyping of nine stable allolines isolated in the offspring from crossing of T. dicoccum x T. aestivum L. using 21 microsatellite (simple sequence repeats-SSR) markers and two cytoplasmic mitochondrial markers to orf256, rps19-p genes; evaluation of drought tolerance of allolines at different stages of ontogenesis (growth parameters, relative water content, quantum efficiency of Photosystem II, electron transport rate, energy dissipated in Photosystem II); and the study of drought tolerance regulator gene Dreb-1 with allele-specific PCR (AS-MARKER) and partial sequence analysis. Most allolines differ in genomic composition and T. dicoccum introgressions. Four allolines-D-b-05, D-d-05, D-d-05b, and D-41-05-revealed signs of drought tolerance of varying degrees. The more drought tolerant D-41-05 line was also characterized by Dreb-B1 allele introgression from T. dicoccum. A number of non-specific patterns and significant differences in allolines in regulation of physiological parameters in drought conditions is identified. Changes in photosynthetic activity in stress-drought are shown to reflect the level of drought tolerance of the forms studied. The contribution of different combinations of nuclear/cytoplasmic genome and alleles of Dreb-1 gene in allolines to the formation of stress tolerance and photosynthetic activity is discussed.

Mesenchymal stem cells alleviate acute kidney injury via miR-107-mediated regulation of ribosomal protein S19.

BACKGROUND: The characteristics of mesenchymal stem cells (MSCs) in the repair of acute kidney injury (AKI) have been extensively studied. However, some potential molecular mechanisms remain indistinct. The aim of this study was to combine published microRNA (miRNA) transcriptional profiling with quantitative proteomic analyses to reveal specific miRNAs or genes for MSC-based therapy in AKI. METHODS: Transcriptome data containing significantly changed miRNAs in renal tissue from AKI mice treated with and without MSCs were downloaded. Proteomics resources were downloaded from a human proximal renal tubule cell line (HK-2) that served as a good in vitro model for AKI treated with MSCs. We connected the proteomics data with transcriptional records based on miRNA function. Differentially expressed genes (DEGs) were sorted. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis was conducted, and protein-protein interaction (PPI) chains were formed. The genes identified in the analyses were verified in a cisplatin-induced AKI rat model and in HK-2 cells exposed to cisplatin and cocultured with MSCs. RESULTS: A total of 207 specific DEGs were sorted. The ribosomal pathway was identified in pathway enrichment, and ribosomal proteins were identified from the PPI network complex. The targeting of the microRNAs, miR-107 to RPS19, was directly verified by the dual-luciferase method. miR-107 knockdown induced RPS19 expression, protected HK-2 cells from cisplatin-induced apoptosis, and promoted cell proliferation. CONCLUSIONS: By analyzing comprehensive bioinformatics data, we have confirmed the DEGs and pathways in AKI treated with MSCs. Bone marrow-derived MSCs reduce miR-107 expression and increase RPS19 expression by repressing the proliferation of cisplatin-induced AKI cells and initiating apoptosis.

Blocking Macrophage Migration Inhibitory Factor Protects Against Cisplatin-Induced Acute Kidney Injury in Mice.

Macrophage migration inhibitory factor (MIF) is elevated in patients with acute kidney injury (AKI) and is suggested as a potential predictor for renal replacement therapy in AKI. In this study, we found that MIF also plays a pathogenic role and is a therapeutic target for AKI. In a cisplatin-induced AKI mouse model, elevated plasma MIF correlated with increased serum creatinine and the severity of renal inflammation and tubular necrosis, whereas deletion of MIF protected the kidney from cisplatin-induced AKI by largely improving renal functional and histological injury, and suppressing renal inflammation including upregulation of cytokines such as interleukin (IL)-1ß, tumor necrosis factor-alpha (TNF-α), IL-6, inducible nitric oxide synthase (iNOS), MCP-1, IL-8, and infiltration of macrophages, neutrophils, and T cells. We next developed a novel therapeutic strategy for AKI by blocking the endogenous MIF with an MIF inhibitor, ribosomal protein S19 (RPS19). Similar to the MIF-knockout mice, treatment with RPS19, but not the mutant RPS19, suppressed cisplatin-induced AKI. Mechanistically, we found that both genetic knockout and pharmacological inhibition of MIF protected against AKI by inactivating the CD74-nuclear factor κB (NF-κB) signaling. In conclusion, MIF is pathogenic in cisplatin-induced AKI. Targeting MIF with an MIF inhibitor RPS19 could be a promising therapeutic potential for AKI.

Flavonoids Luteolin and Quercetin Inhibit RPS19 and contributes to metastasis of cancer cells through c-Myc reduction.

Flavonoids luteolin and quercetin can inhibit growth and metastasis of cancer cells. In our previous report, luteolin and quercetin was shown to block Akt/mTOR/c-Myc signaling. Here, we found luteolin and quercetin reduced protein level and transactivation activity of RPS19 in A431-III cells, which is isolated from parental A431 (A431-P) cell line. Further investigation the inhibitory mechanism of luteolin and quercetin on RPS19, we found c-Myc binding sites on RPS19 promoter. The Akt inhibitor LY294002, mTOR inhibitor rapamycin and c-Myc inhibitor 10058-F4 significantly suppressed RPS19 expression and transactivation activities. Overexpression and knockdown of c-Myc in cancer cells show RPS19 expression was regulated by c-Myc. Furthermore, Knockdown and overexpression of RPS19 was used to analyze of the function of RPS19 in cancer cells. The epithelial-mesenchymal transition (EMT) markers and metastasis abilities of cancer cells were also regulated by RPS19. These data suggest that luteolin and quercetin might inhibit metastasis of cancer cells by blocking Akt/mTOR/c-Myc signaling pathway to suppress RPS19-activated EMT signaling.

A functional assay for the clinical annotation of genetic variants of uncertain significance in Diamond-Blackfan anemia.

Diamond-Blackfan anemia (DBA) is a rare genetic hypoplasia of erythroid progenitors characterized by mild to severe anemia and associated with congenital malformations. Clinical manifestations in DBA patients are quite variable and genetic testing has become a critical factor in establishing a diagnosis of DBA. The majority of DBA cases are due to heterozygous loss-of-function mutations in ribosomal protein (RP) genes. Causative mutations are fairly straightforward to identify in the case of large deletions and frameshift and nonsense mutations found early in a protein coding sequence, but diagnosis becomes more challenging in the case of missense mutations and small in-frame indels. Our group recently characterized the phenotype of lymphoblastoid cell lines established from DBA patients with pathogenic lesions in RPS19 and observed that defective pre-rRNA processing, a hallmark of the disease, was rescued by lentiviral vectors expressing wild-type RPS19. Here, we use this complementation assay to determine whether RPS19 variants of unknown significance are capable of rescuing pre-rRNA processing defects in these lymphoblastoid cells as a means of assessing the effects of these sequence changes on the function of the RPS19 protein. This approach will be useful in differentiating pathogenic mutations from benign polymorphisms in identifying causative genes in DBA patients.

Complete Chloroplast Genome Sequences of Four Meliaceae Species and Comparative Analyses.

The Meliaceae family mainly consists of trees and shrubs with a pantropical distribution. In this study, the complete chloroplast genomes of four Meliaceae species were sequenced and compared with each other and with the previously published Azadirachta indica plastome. The five plastomes are circular and exhibit a quadripartite structure with high conservation of gene content and order. They include 130 genes encoding 85 proteins, 37 tRNAs and 8 rRNAs. Inverted repeat expansion resulted in a duplication of rps19 in the five Meliaceae species, which is consistent with that in many other Sapindales, but different from many other rosids. Compared to Azadirachta indica, the four newly sequenced Meliaceae individuals share several large deletions, which mainly contribute to the decreased genome sizes. A whole-plastome phylogeny supports previous findings that the four species form a monophyletic sister clade to Azadirachta indica within the Meliaceae. SNPs and indels identified in all complete Meliaceae plastomes might be suitable targets for the future development of genetic markers at different taxonomic levels. The extended analysis of SNPs in the matK gene led to the identification of four potential Meliaceae-specific SNPs as a basis for future validation and marker development.