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1.
J Sch Health ; 92(8): 804-811, 2022 08.
Article in English | MEDLINE | ID: mdl-35445407

ABSTRACT

BACKGROUND: Since the inception of the Youth Risk Behavior Surveillance System in 1991, all surveys have been conducted in schools, using paper and pencil instruments (PAPI). For the 2019 YRBSS, sites were offered the opportunity to conduct their surveys using electronic data collection. This study aimed to determine whether differences in select metrics existed between students who completed the survey electronically versus using PAPI. METHODS: Thirty risk behaviors were examined in this study. Data completeness, response rates and bivariate comparisons of risk behavior prevalence between administration modes were examined. RESULTS: Twenty-nine of 30 questions examined had more complete responses among students using electronic surveys. Small differences were found for student and school response rates between modes. Twenty-five of 30 adolescent risk behaviors showed no mode effect. CONCLUSIONS: Seven of 44 states and DC participated electronically. Because survey data were more complete; school and student response rates were consistent; and minor differences existed in risk behaviors between modes, the acceptability of collecting data electronically was demonstrated.


Subject(s)
Adolescent Behavior , Population Surveillance , Adolescent , Electronics , Humans , Risk-Taking , Surveys and Questionnaires , United States
2.
Nutrients ; 12(6)2020 Jun 08.
Article in English | MEDLINE | ID: mdl-32521660

ABSTRACT

Flavonoids are a class of polyphenolic compounds that naturally occur in plants. Sub-groups of flavonoids include flavone, flavonol, flavanone, flavanonol, anthocyanidin, flavanol and isoflavone. The various modifications on flavonoid molecules further increase the diversity of flavonoids. Certain crops are famous for being enriched in specific flavonoids. For example, anthocyanins, which give rise to a purplish color, are the characteristic compounds in berries; flavanols are enriched in teas; and isoflavones are uniquely found in several legumes. It is widely accepted that the antioxidative properties of flavonoids are beneficial for human health. In this review, we summarize the classification of the different sub-groups of flavonoids based on their molecular structures. The health benefits of flavonoids are addressed from the perspective of their molecular structures. The flavonoid biosynthesis pathways are compared among different crops to highlight the mechanisms that lead to the differential accumulation of different sub-groups of flavonoids. In addition, the mechanisms and genes involved in the transport and accumulation of flavonoids in crops are discussed. We hope the understanding of flavonoid accumulation in crops will guide the proper balance in their consumption to improve human health.


Subject(s)
Crops, Agricultural/metabolism , Flavonoids/chemistry , Flavonoids/classification , ATP-Binding Cassette Transporters/metabolism , Anthocyanins , Antioxidants , Female , Flavonoids/biosynthesis , Flavonoids/metabolism , Humans , Isoflavones , Male , Molecular Structure , Polyphenols
3.
J Exp Bot ; 71(10): 2970-2981, 2020 05 30.
Article in English | MEDLINE | ID: mdl-32061092

ABSTRACT

Transcription factors (TFs) help plants respond to environmental stresses by regulating gene expression. Up till now, studies on the MYB family of TFs have mainly focused on the highly abundant R2R3-subtype. While the less well-known 1R-subtype has been generally shown to enhance abscisic acid (ABA) sensitivity by acting as transcriptional activators, the mechanisms of their functions are unclear. Here we identified an ABA sensitivity-associated gene from soybean, ABA-Sensitive 1 (GmABAS1), of the 1R-subtype of MYB. Using the GFP-GmABAS1 fusion protein, we demonstrated that GmABAS1 is localized in the nucleus, and with yeast reporter systems, we showed that it is a transcriptional repressor. We then identified the target gene of GmABAS1 to be Glyma.01G060300, an annotated ABI five-binding protein 3 and showed that GmABAS1 binds to the promoter of Glyma.01G060300 both in vitro and in vivo. Furthermore, Glyma.01G060300 and GmABAS1 exhibited reciprocal expression patterns under osmotic stress, inferring that GmABAS1 is a transcriptional repressor of Glyma.01G060300. As a further confirmation, AtAFP2, an orthologue of Glyma.01G060300, was down-regulated in GmABAS1-transgenic Arabidopsis thaliana, enhancing the plant's sensitivity to ABA. This is the first time a 1R-subtype of MYB from soybean has been reported to enhance ABA sensitivity by acting as a transcriptional repressor.


Subject(s)
Abscisic Acid , Glycine max , Gene Expression Regulation, Plant , Plant Proteins/genetics , Plant Proteins/metabolism , Plants, Genetically Modified/genetics , Plants, Genetically Modified/metabolism , Glycine max/genetics , Glycine max/metabolism , Stress, Physiological , Transcription Factors/genetics , Transcription Factors/metabolism
4.
EMBO Mol Med ; 9(2): 251-264, 2017 02.
Article in English | MEDLINE | ID: mdl-28011860

ABSTRACT

Although remnant cardiomyocytes (CMs) possess a certain degree of proliferative ability, efficiency is too low for cardiac regeneration after injury. In this study, we identified a distinct stage within the initiation phase of CM reprogramming before the MET process, and microarray analysis revealed the strong up-regulation of several mitosis-related genes at this stage of reprogramming. Several candidate genes were selected and tested for their ability to induce CM proliferation. Delivering a cocktail of three genes, FoxM1, Id1, and Jnk3-shRNA (FIJs), induced CMs to re-enter the cell cycle and complete mitosis and cytokinesis in vitro More importantly, this gene cocktail increased CM proliferation in vivo and significantly improved cardiac function and reduced fibrosis after myocardial infarction. Collectively, our findings present a cocktail FIJs that may be useful in cardiac regeneration and also provide a practical strategy for probing reprogramming assays for regeneration of other tissues.


Subject(s)
Cell Proliferation , Genetic Therapy/methods , Myocardial Infarction/therapy , Myocytes, Cardiac/physiology , Regeneration , Animals , Dependovirus/genetics , Forkhead Box Protein M1/genetics , Genetic Vectors , Inhibitor of Differentiation Protein 1/genetics , Mice, Inbred C57BL , Mitogen-Activated Protein Kinase 10/genetics , RNA, Small Interfering/genetics , Regenerative Medicine/methods , Transduction, Genetic , Treatment Outcome
5.
Can J Diabetes ; 40(6): 535-542, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27373434

ABSTRACT

BACKGROUND: Legislative changes since 2007 have given Alberta pharmacists additional authorizations and new practice settings, which should enhance provision of clinical services to patients. This study examined whether these changes are related to the number of diabetes management activities provided by pharmacists. METHODS: Cross-sectional surveys of Alberta pharmacists were conducted in 2006 and 2015. Both questionnaires contained 63 diabetes management activities, with response options to indicate how frequently the activity was provided. Respondents were grouped by survey year, practice setting, diabetes-specific training and additional authorizations. The number of diabetes management activities provided often or always were compared among groups by using analysis of variance. RESULTS: Data from 128 pharmacists participating in the 2006 survey were compared with 256 pharmacists participating in the 2015 survey; overall mean age was 41.6 (±10.9) years, 245 (64%) were women, mean duration of practice was 16.1 (±11.8) years, 280 (73%) were community pharmacists, 75 (20%) were certified diabetes educators (CDEs), and 100 (26%) had additional prescribing authorization (APA). Pharmacists provided a mean of 28.7 (95% CI 26.3 to 31.2) diabetes management activities in 2006 and 35.2 (95% CI 33.4-37.0) activities in 2015 (p<0.001). Pharmacists who were CDEs provided significantly more activities compared to other pharmacists (p<0.001). In 2015, working in a primary care network and having APA were also associated with provision of more activities (p<0.05 for both comparisons). CONCLUSIONS: Pharmacists provided more diabetes management activities in 2015 than in 2006. The number of diabetes management activities was also associated with being a CDE, working in a primary care network or having APA.


Subject(s)
Attitude of Health Personnel , Certification/standards , Diabetes Mellitus/drug therapy , Drug Prescriptions/statistics & numerical data , Hypoglycemic Agents/therapeutic use , Pharmacists/standards , Adult , Cross-Sectional Studies , Diabetes Mellitus/diagnosis , Diabetes Mellitus/epidemiology , Disease Management , Female , Follow-Up Studies , Humans , Male , Professional Role , Prognosis , Surveys and Questionnaires
6.
Hum Vaccin Immunother ; 11(4): 1065-73, 2015.
Article in English | MEDLINE | ID: mdl-25751377

ABSTRACT

Acinetobacter baumannii (Ab) is a global emerging bacterium causing nosocomial infections such as pneumonia, meningitis, bacteremia and soft tissue infections especially in intensive care units. Since Ab is resistant to almost all conventional antibiotics, it is now one of the 6 top-priorities of the dangerous microorganisms listed by the Infectious Disease Society of America. The development of vaccine is one of the most promising and cost-effective strategies to prevent infections. In this study, we identified potential protective vaccine candidates using reverse vaccinology. We have analyzed 14 on-line available Ab genome sequences and found 2752 homologous core genes. Using information obtained from immuno-proteomic experiments, published proteomic information and the bioinformatics PSORTb v3.0 software to predict the location of extracellular and/or outer membrane proteins, 77 genes were identified and selected for further studies. After excluding those antigens have been used as vaccine candidates reported by the in silico search-engines of PubMed and Google Scholar, 13 proteins could potentially be vaccine candidates. We have selected and cloned the genes of 3 antigens that were further expressed and purified. These antigens were found to be highly immunogenic and conferred partial protection (60%) in a pneumonia animal model. The strategy described in the present study incorporates the advantages of reverse vaccinology, bioinformatics and immuno-proteomic platform technologies and is easy to perform to identify novel immunogens for multi-component vaccines development.


Subject(s)
Acinetobacter baumannii/immunology , Bacterial Vaccines/immunology , Acinetobacter Infections/immunology , Acinetobacter Infections/prevention & control , Animals , Bacterial Vaccines/therapeutic use , Computational Biology/methods , Enzyme-Linked Immunosorbent Assay , Humans , Mice , Mice, Inbred C57BL , Pneumonia/immunology , Pneumonia/prevention & control
7.
J Glob Health ; 4(1): 010402, 2014 Jun.
Article in English | MEDLINE | ID: mdl-24976961

ABSTRACT

BACKGROUND: To provide an estimate for the burden of neural tube defects (NTD) in low- and middle-income countries (LMIC) and explore potential public health policies that may be implemented. Although effective interventions are available to prevent NTD, there is still considerable childhood morbidity and mortality present in LMIC. METHODS: A search of Medline, EMBASE, Global Health Library and PubMed identified 37 relevant studies that provided estimates of the burden of NTD in LMIC. Information on burden of total NTD and specific NTD types was separated according to the denominator into two groups: (i) estimates based on the number of live births only; and (ii) live births, stillbirths and terminations. The data was then extracted and analysed. RESULTS: The search retrieved NTD burden from 18 countries in 6 WHO regions. The overall burden calculated using the median from studies based on livebirths was 1.67/1000 (IQR = 0.98-3.49) for total NTD burden, 1.13/1000 (IQR = 0.75-1.73) for spina bifida, 0.25/1000 (IQR = 0.08-1.07) for anencephaly and 0.15/1000 (IQR = 0.08-0.23) for encephalocele. Corresponding estimates based on all pregnancies resulting in live births, still births and terminations were 2.55/1000 (IQR = 1.56-3.91) for total NTD burden, 1.04/1000 (IQR = 0.67-2.48) for spina bifida, 1.03/1000 (IQR = 0.67-1.60) for anencephaly and 0.21 (IQR = 0.16-0.28) for encephalocele. This translates into about 190 000neonates who are born each year with NTD in LMIC. CONCLUSION: Limited available data on NTD in LMIC indicates the need for additional research that would improve the estimated burden of NTD and recommend suitable aid policies through maternal education on folic acid supplementation or food fortification.

8.
J Am Anim Hosp Assoc ; 50(4): 284-90, 2014.
Article in English | MEDLINE | ID: mdl-24855093

ABSTRACT

A bronchopleural fistula (BPF) can lead to continuous pneumothorax and is rarely reported clinically in dogs. This report describes computed tomographic (CT) findings in two dogs with BPFs and subsequent continuous pneumothoraces that necessitated thoracotomy. Both dogs had a peripheral BPF in the right caudal lung lobe. The fistula in one dog was secondary to a previous foreign body migration, and the fistula in the other was thought to be secondary to dirofilariasis. On both CT examinations, a dilated subsegmental bronchus was seen communicating with the pleural space at the center of a focal, concave region of parenchymal consolidation. Multiplanar reformatting aided in identification and characterization of the BPF. The pneumothoraces resolved after right caudal lobectomy in both dogs. CT has the potential to identify BPFs, such as secondary to foreign body migration or dirofilariasis.


Subject(s)
Bronchial Fistula/veterinary , Dog Diseases/diagnostic imaging , Pleural Diseases/veterinary , Pneumothorax/veterinary , Respiratory Tract Fistula/veterinary , Animals , Bronchial Fistula/complications , Bronchial Fistula/diagnostic imaging , Diagnosis, Differential , Dog Diseases/etiology , Dog Diseases/pathology , Dogs , Female , Male , Pleural Diseases/complications , Pleural Diseases/diagnostic imaging , Pneumothorax/diagnostic imaging , Pneumothorax/etiology , Radiography, Thoracic/veterinary , Respiratory Tract Fistula/complications , Respiratory Tract Fistula/diagnostic imaging , Tomography, X-Ray Computed/veterinary
9.
J Feline Med Surg ; 14(12): 919-23, 2012 Dec.
Article in English | MEDLINE | ID: mdl-22811480

ABSTRACT

A 4-year-old castrated male Russian Blue cat was evaluated for acute right hind limb lameness 18 months after receiving a renal transplant. Radiographs showed a subluxated right femoral head and lysis of the acetabulum and femoral neck. A femoral head and neck ostectomy was performed on the right coxofemoral joint. Histologic evaluation of the right femoral head revealed lesions indicative of a chronic, granulomatous osteomyelitis and periostitis associated with an intralesional Mycobacterium species. However, the cat's clinical condition declined despite treatment and the owner elected humane euthanasia. All renal transplant recipients receive immunosuppressive therapy to prevent allograft rejection. The non-tuberculous mycobacterial infection of the coxofemoral joint was thought to develop secondary to long-term immunosuppressive treatment. This report illustrates the need to consider these rare opportunistic infections even many months to years following renal transplantation. Early awareness, stringent immunosuppressive drug monitoring and targeted treatment once a diagnosis has been made may be important in the successful management and prevention of mycobacterial infections in this population of patients.


Subject(s)
Cat Diseases/diagnosis , Cat Diseases/microbiology , Kidney Transplantation/veterinary , Mycobacterium Infections/veterinary , Osteomyelitis/veterinary , Animals , Cats , Fatal Outcome , Immunocompromised Host , Kidney Transplantation/adverse effects , Lymph Nodes/microbiology , Lymph Nodes/pathology , Male , Mycobacterium/isolation & purification , Mycobacterium Infections/diagnosis , Osteomyelitis/diagnosis
10.
Blood ; 108(6): 2064-71, 2006 Sep 15.
Article in English | MEDLINE | ID: mdl-16690966

ABSTRACT

Erythroid progenitors differentiate in erythroblastic islands, bone marrow niches composed of erythroblasts surrounding a central macrophage. Evidence suggests that within islands adhesive interactions regulate erythropoiesis and apoptosis. We are exploring whether erythroid intercellular adhesion molecule 4 (ICAM-4), an immunoglobulin superfamily member, participates in island formation. Earlier, we identified alpha(V) integrins as ICAM-4 counterreceptors. Because macrophages express alpha(V), ICAM-4 potentially mediates island attachments. To test this, we generated ICAM-4 knock-out mice and developed quantitative, live cell techniques for harvesting intact islands and for re-forming islands in vitro. We observed a 47% decrease in islands reconstituted from ICAM-4 null marrow compared to wild-type marrow. We also found a striking decrease in islands formed in vivo in knock-out mice. Further, peptides that block ICAM-4/alpha(V) adhesion produced a 53% to 57% decrease in reconstituted islands, strongly suggesting that ICAM-4 binding to macrophage alpha(V) functions in island integrity. Importantly, we documented that alpha(V) integrin is expressed in macrophages isolated from erythroblastic islands. Collectively, these data provide convincing evidence that ICAM-4 is critical in erythroblastic island formation via ICAM-4/alpha(V) adhesion and also demonstrate that the novel experimental strategies we developed will be valuable in exploring molecular mechanisms of erythroblastic island formation and their functional role in regulating erythropoiesis.


Subject(s)
Cell Adhesion Molecules/physiology , Erythroblasts/cytology , Erythroblasts/metabolism , Erythropoiesis/physiology , Animals , Base Sequence , Bone Marrow Cells/cytology , Bone Marrow Cells/metabolism , Cell Adhesion Molecules/chemistry , Cell Adhesion Molecules/deficiency , Cell Adhesion Molecules/genetics , DNA/genetics , Erythroid Precursor Cells/cytology , Erythroid Precursor Cells/metabolism , Erythropoiesis/genetics , Gene Targeting , Integrin alphaV/metabolism , Mice , Mice, Inbred C57BL , Mice, Knockout , Models, Molecular , Protein Structure, Tertiary
11.
J Biol Chem ; 281(18): 12468-74, 2006 May 05.
Article in English | MEDLINE | ID: mdl-16537540

ABSTRACT

Activation of protein 4.1R exon 16 (E16) inclusion during erythropoiesis represents a physiologically important splicing switch that increases 4.1R affinity for spectrin and actin. Previous studies showed that negative regulation of E16 splicing is mediated by the binding of heterogeneous nuclear ribonucleoprotein (hnRNP) A/B proteins to silencer elements in the exon and that down-regulation of hnRNP A/B proteins in erythroblasts leads to activation of E16 inclusion. This article demonstrates that positive regulation of E16 splicing can be mediated by Fox-2 or Fox-1, two closely related splicing factors that possess identical RNA recognition motifs. SELEX experiments with human Fox-1 revealed highly selective binding to the hexamer UGCAUG. Both Fox-1 and Fox-2 were able to bind the conserved UGCAUG elements in the proximal intron downstream of E16, and both could activate E16 splicing in HeLa cell co-transfection assays in a UGCAUG-dependent manner. Conversely, knockdown of Fox-2 expression, achieved with two different siRNA sequences resulted in decreased E16 splicing. Moreover, immunoblot experiments demonstrate mouse erythroblasts express Fox-2. These findings suggest that Fox-2 is a physiological activator of E16 splicing in differentiating erythroid cells in vivo. Recent experiments show that UGCAUG is present in the proximal intron sequence of many tissue-specific alternative exons, and we propose that the Fox family of splicing enhancers plays an important role in alternative splicing switches during differentiation in metazoan organisms.


Subject(s)
Blood Proteins/physiology , DNA-Binding Proteins/metabolism , Microtubule-Associated Proteins/physiology , RNA-Binding Proteins/metabolism , Repressor Proteins/metabolism , Transcription Factors/metabolism , Amino Acid Motifs , Base Sequence , Blood Proteins/metabolism , Cell Differentiation , Cytoskeletal Proteins , Down-Regulation , Erythroblasts/metabolism , Exons , Gene Expression Regulation , HeLa Cells , Heterogeneous-Nuclear Ribonucleoproteins/metabolism , Humans , Introns , Membrane Proteins , Microtubule-Associated Proteins/metabolism , Molecular Sequence Data , RNA Splicing Factors , RNA, Small Interfering/metabolism
12.
Blood ; 106(6): 2200-5, 2005 Sep 15.
Article in English | MEDLINE | ID: mdl-15933051

ABSTRACT

Enucleation, a rare feature of mammalian differentiation, occurs in 3 cell types: erythroblasts, lens epithelium, and keratinocytes. Previous investigations suggest that caspase activation functions in lens epithelial and keratinocyte enucleation, as well as in early erythropoiesis encompassing erythroid burst-forming unit (BFU-E) differentiation to proerythroblast. To determine whether caspase activation contributes to later erythropoiesis and whether nuclear substructures other than chromatin reorganize, we analyzed distributions of nuclear subcompartment proteins and assayed for caspase-induced cleavage of subcompartmental target proteins in mouse erythroblasts. We found that patterns of lamin B in the filamentous network interacting with both the nuclear envelope and DNA, nuclear matrix protein NuMA (Nuclear mitotic apparatus), and splicing factors Sm and SC35 persisted during nuclear condensation, consistent with effective transcription of genes expressed late in differentiation. Thus, nuclear reorganization prior to enucleation is selective, allowing maintenance of critical transcriptional processes independent of extensive chromosomal reorganization. Consistent with these data, we found no evidence for caspase-induced cleavage of major nuclear subcompartment proteins during late erythropoiesis, in contrast to what has been observed in early erythropoiesis and in lens epithelial and keratinocyte differentiation. These findings imply that nuclear condensation and extrusion during terminal erythroid differentiation involve novel mechanisms that do not entail major activation of apoptotic machinery.


Subject(s)
Caspases/metabolism , Cell Nucleus Structures/physiology , Cell Nucleus/ultrastructure , Erythropoiesis , Nuclear Proteins/metabolism , Animals , Cell Nucleus/physiology , DNA/metabolism , Erythroblasts/ultrastructure , Lamin Type B/metabolism , Mice , Mice, Inbred Strains , Nuclear Matrix-Associated Proteins/metabolism
13.
Blood ; 103(5): 1912-9, 2004 Mar 01.
Article in English | MEDLINE | ID: mdl-14563645

ABSTRACT

During erythroblast enucleation, nuclei surrounded by plasma membrane separate from erythroblast cytoplasm. A key aspect of this process is sorting of erythroblast plasma membrane components to reticulocytes and expelled nuclei. Although it is known that cytoskeletal elements actin and spectrin partition to reticulocytes, little is understood about molecular mechanisms governing plasma membrane protein sorting. We chose glycophorin A (GPA) as a model integral protein to begin investigating protein-sorting mechanisms. Using immunofluorescence microscopy and Western blotting we found that GPA sorted predominantly to reticulocytes. We hypothesized that the degree of skeletal linkage might control the sorting pattern of transmembrane proteins. To explore this hypothesis, we quantified the extent of GPA association to the cytoskeleton in erythroblasts, young reticulocytes, and mature erythrocytes using fluorescence imaged microdeformation (FIMD) and observed that GPA underwent dramatic reorganization during terminal differentiation. We discovered that GPA was more connected to the membrane cytoskeleton, either directly or indirectly, in erythroblasts and young reticulocytes than in mature cells. We conclude that skeletal protein association can regulate protein sorting during enucleation. Further, we suggest that the enhanced rigidity of reticulocyte membranes observed in earlier investigations results, at least in part, from increased connectivity of GPA with the spectrin-based skeleton.


Subject(s)
Cell Nucleus/metabolism , Cytoskeleton/metabolism , Erythroblasts/cytology , Glycophorins/physiology , Actins/metabolism , Animals , Blotting, Western , Bone Marrow Cells/metabolism , Bone and Bones/metabolism , Cell Differentiation , Cell Line , Cell Membrane/metabolism , Erythrocyte Membrane/metabolism , Erythrocytes/metabolism , Glycophorins/chemistry , Glycophorins/metabolism , Lipid Metabolism , Mice , Mice, Inbred BALB C , Microscopy, Fluorescence , Reticulocytes/metabolism , Spectrin/metabolism
14.
Blood ; 101(12): 5039-45, 2003 Jun 15.
Article in English | MEDLINE | ID: mdl-12586610

ABSTRACT

Ribosomal protein S19 (RPS19) is frequently mutated in Diamond-Blackfan anemia (DBA), a rare congenital hypoplastic anemia. Recent studies have shown that RPS19 expression decreases during terminal erythroid differentiation. Currently no information is available on the subcellular localization of normal RPS19 and the potential effects of various RPS19 mutations on cellular localization. In the present study, using wild-type and mutant RPS19 cDNA, we explored the subcellular distribution of normal and mutant proteins in a fibroblast cell line (Cos-7 cells). RPS19 was detected primarily in the nucleus, and more specifically in the nucleoli, where RPS19 colocalized with the nucleolar protein nucleolin. Using various N-terminal and C-terminal deletion constructs, we identified 2 nucleolar localization signals (NoSs) in RPS19: the first comprising amino acids Met1 to Arg16 in the NH2-terminus and the second comprising Gly120 to Asn142 in the COOH-terminus. Importantly, 2 mutations identified in DBA patients, Val15Phe and Gly127Gln, each of which localized to 1 of the 2 NoS, failed to localize RPS19 to the nucleolus. In addition to their mislocalization, there was a dramatic decrease in the expression of the 2 mutant proteins compared to the wild type. This decrease in protein expression was specific for the mutant RPS19, since expression of other proteins was normal. The present findings enable us to document the nucleolar localization signals in RPS19 and help define the phenotypic consequences of some mutations in RPS19 in DBA.


Subject(s)
Anemia, Diamond-Blackfan/genetics , Cell Nucleolus/chemistry , Mutation , Ribosomal Proteins/analysis , Ribosomal Proteins/genetics , Animals , Biological Transport , COS Cells , Cloning, Molecular , DNA, Complementary/chemistry , Female , Gene Expression , Humans , Infant , Infant, Newborn , Male , Microscopy, Fluorescence , Ribosomal Proteins/chemistry , Structure-Activity Relationship , Transfection
15.
EMBO J ; 21(22): 6195-204, 2002 Nov 15.
Article in English | MEDLINE | ID: mdl-12426391

ABSTRACT

A physiologically important alternative pre-mRNA splicing switch, involving activation of protein 4.1R exon 16 (E16) splicing, is required for the establishment of proper mechanical integrity of the erythrocyte membrane during erythropoiesis. Here we identify a conserved exonic splicing silencer element (CE(16)) in E16 that interacts with hnRNP A/B proteins and plays a role in repression of E16 splicing during early erythropoiesis. Experiments with model pre-mRNAs showed that CE(16) can repress splicing of upstream introns, and that mutagenesis or replacement of CE(16) can relieve this inhibition. An affinity selection assay with biotinylated CE(16) RNA demonstrated specific binding of hnRNP A/B proteins. Depletion of hnRNP A/B proteins from nuclear extract significantly increased E16 inclusion, while repletion with recombinant hnRNP A/B restored E16 silencing. Most importantly, differentiating mouse erythroblasts exhibited a stage-specific activation of the E16 splicing switch in concert with a dramatic and specific down-regulation of hnRNP A/B protein expression. These findings demonstrate that natural developmental changes in hnRNP A/B proteins can effect physiologically important switches in pre-mRNA splicing.


Subject(s)
Alternative Splicing , Cytoskeletal Proteins , Erythroid Precursor Cells/metabolism , Erythropoiesis/genetics , Gene Expression Regulation/genetics , Gene Silencing , Heterogeneous-Nuclear Ribonucleoprotein Group A-B/biosynthesis , Membrane Proteins , Neuropeptides , Proteins/genetics , RNA Precursors/metabolism , Regulatory Sequences, Nucleic Acid , Animals , Base Sequence , Consensus Sequence , Erythroid Precursor Cells/cytology , Exons/genetics , HeLa Cells , Heterogeneous-Nuclear Ribonucleoprotein Group A-B/genetics , Humans , Introns/genetics , Mice , Molecular Sequence Data , Mutagenesis , Protein Binding , RNA Precursors/genetics , RNA-Binding Proteins/metabolism , Sequence Alignment , Sequence Homology, Nucleic Acid , Species Specificity , Transfection , Vertebrates/genetics , Xenopus laevis
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