Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 30
Filtrar
1.
J Biochem ; 174(4): 371-382, 2023 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-37400983

RESUMO

Heterochromatin protein 1 (HP1) is an evolutionarily conserved protein that plays a critical role in heterochromatin assembly. HP1 proteins share a basic structure consisting of an N-terminal chromodomain (CD) and a C-terminal chromoshadow domain (CSD) linked by a disordered hinge region. The CD recognizes histone H3 lysine 9 methylation, a hallmark of heterochromatin, while the CSD forms a dimer to recruit other chromosomal proteins. HP1 proteins have been shown to bind DNA or RNA primarily through the hinge region. However, how DNA or RNA binding contributes to their function remains elusive. Here, we focus on Chp2, one of the two HP1 proteins in fission yeast, and investigate how Chp2's DNA-binding ability contributes to its function. Similar to other HP1 proteins, the Chp2 hinge exhibits clear DNA-binding activity. Interestingly, the Chp2 CSD also shows robust DNA-binding activity. Mutational analysis revealed that basic residues in the Chp2 hinge and at the N-terminus of the CSD are essential for DNA binding, and the combined amino acid substitutions of these residues alter Chp2 stability, impair Chp2 heterochromatin localization and lead to a silencing defect. These results demonstrate that the cooperative DNA-binding activities of Chp2 play an important role in heterochromatin assembly in fission yeast.


Assuntos
Heterocromatina , Schizosaccharomyces , Heterocromatina/metabolismo , Schizosaccharomyces/genética , Schizosaccharomyces/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Homólogo 5 da Proteína Cromobox , RNA/metabolismo
2.
MicroPubl Biol ; 20232023.
Artigo em Inglês | MEDLINE | ID: mdl-36820392

RESUMO

The CRSIPR/Cas9 system has been applied to fission yeast, but there remain some rooms for improvement. Here we report that the weaker versions of the adh1 + promoter, adh11 and adh41 promoters, for the potentially cytotoxic Cas9 achieved highly efficient mutagenesis and gene deletion at the ade6 + locus. Employing a drug-selectable marker instead of conventional auxotrophic markers, our new vector system is compatible with a variety of experimental settings including prototrophic/auxotrophic strains and complete/minimal media.

3.
Anal Sci ; 38(8): 1115-1121, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35718829

RESUMO

Detergent removal in glycolipid after sample preparation, such as enzymatic reaction or isolation of detergent-resistant membrane microdomain, is indispensable for further structural characterization. We previously established the rapid and effective method of detergent removal in glycolipid samples from glass test tube using 1,2-dichloroethane (DCE) washing. However, the use of DCE has several drawbacks, such as environmental risks, harmful effects (potentially carcinogenic), and high vaporability and flammability. To solve the issue, we used ionic liquids to remove detergents from glycolipid samples, and found 1-butyl-3-methylimidazolium iodide was a suitable alternative for DCE.


Assuntos
Líquidos Iônicos , Detergentes/química , Glicolipídeos/química , Iodetos , Líquidos Iônicos/química
4.
Anal Sci ; 37(11): 1491-1495, 2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34690230

RESUMO

Matrix-assisted laser desorption/ionization-based mass spectrometry imaging (MSI) of separated lipids on thin-layer chromatography (TLC) plates or followed by blotted hydrophilic polyvinylidene fluoride (PVDF) membranes has become a powerful tool in lipidomic analyses. However, background peaks in MS spectra often cover lipid peaks in a low amount/ionization effect; consequently, only low intensities/resolutions MSI are obtained. To address the aforementioned problem, we attempted 1,2-dichloroethane pre-washing of TLC plates before development and found that backgrounds could successfully be removed from the TLC plate or PVDF membrane.


Assuntos
Glicerol , Glicoesfingolipídeos , Cromatografia em Camada Fina , Ésteres , Dicloretos de Etileno , Ácidos Graxos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
5.
JMIR Res Protoc ; 10(8): e31061, 2021 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-34402802

RESUMO

BACKGROUND: Diabetic kidney disease (DKD) is one of the main complications of type 2 diabetes mellitus (T2DM). DKD is a known risk factor for end-stage renal disease, cardiovascular disease, and all-cause death. Effective intervention for early-stage DKD is vital to slowing down the progression of kidney disease and improve prognoses. Mobile health (mHealth) is reportedly effective in supporting patients' self-care and improving glycemic control, but the impact of mHealth on DKD has yet to be shown. OBJECTIVE: The purpose of this study is to evaluate the efficacy of standard therapy with the addition of a self-management support system, DialBetesPlus, in patients with DKD and microalbuminuria. METHODS: This study is a prospective, randomized, open-label, multicenter clinical trial. The target population consists of 160 patients diagnosed with T2DM accompanied by microalbuminuria. We randomly assigned the patients to 2 groups-the intervention group using DialBetesPlus in addition to conventional therapy and the control group using conventional therapy alone. DialBetesPlus is a smartphone application that supports patients' self-management of T2DM. The study period was 12 months, with a follow-up survey at 18 months. The primary outcome was a change in albuminuria levels at 12 months. Secondary outcomes included changes in physical parameters, blood test results (glycemic control, renal function, and lipid metabolism), lifestyle habits, self-management scores, medication therapy, and quality of life. RESULTS: The study was approved in April 2018. We began recruiting patients in July 2018 and completed recruiting in August 2019. The final 18-month follow-up was conducted in March 2021. We recruited 159 patients and randomly allocated 70 into the intervention group and 61 into the control group, with 28 exclusions due to withdrawal of consent, refusal to continue, or ineligibility. The first results are expected to be available in 2021. CONCLUSIONS: This is the first randomized controlled trial assessing the efficacy of mHealth on early-stage DKD. We expect that albuminuria levels will decrease significantly in the intervention group due to improved glycemic control with ameliorated self-care behaviors. TRIAL REGISTRATION: UMIN-CTR UMIN000033261; https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000037924. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/31061.

6.
Reprod Med Biol ; 19(2): 135-141, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32273818

RESUMO

PURPOSE: We studied the influence of psychological stress during the early neonatal period on sexual maturation and sexual behavior in rats. METHODS: Neonatal male and female rats were divided into control (C) and maternal separation (MS) groups (n = 20-24 per group). The pups in the MS groups were placed in isolation cages for 240 minutes/d from postnatal days 2-11. Vaginal opening (VO) in females and preputial separation (PS) in males (indicators of sexual maturation) were monitored, as was the estrous cycle in females. Thereafter, sexual behavior was monitored twice at 13 and 15 weeks of age. RESULTS: As for sexual maturation, the onset of PS occurred significantly earlier in the MS group than in the C group, whereas the onset of VO did not differ between the groups. The length of the estrous cycle did not differ between the groups. The frequencies of sexual behaviors did not differ between the groups in either sex. CONCLUSIONS: In conclusion, early-life psychological stress induced by MS advanced sexual maturation in male rats, whereas it did not affect sexual maturation in female rats. On the other hand, early-life psychological stress might not affect sexual behavior in adulthood in either sex.

7.
G3 (Bethesda) ; 9(4): 1153-1163, 2019 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-30755408

RESUMO

The CRISPR/Cas9 system enables the editing of genomes of numerous organisms through the induction of the double-strand breaks (DSB) at specific chromosomal targets. We improved the CRISPR/Cas9 system to ease the direct introduction of a point mutation or a tagging sequence into the chromosome by combining it with the noncanonical homology-directed DNA repair (HDR) based genome editing in fission yeast. We constructed convenient cloning vectors, which possessed a guide RNA (gRNA) expression module, or the humanized Streptococcus pyogenes Cas9 gene that is expressed under the control of an inducible promoter to avoid the needless expression, or both a gRNA and Cas9 gene. Using this system, we attempted the short-homology-mediated genome editing and found that the HDR pathway provides high-frequency genome editing at target loci without the need of a long donor DNA. Using short oligonucleotides, we successfully introduced point mutations into two target genes at high frequency. We also precisely integrated the sequences for epitope and GFP tagging using donor DNA possessing short homology into the target loci, which enabled us to obtain cells expressing N-terminally tagged fusion proteins. This system could expedite genome editing in fission yeast, and could be applicable to other organisms.


Assuntos
Edição de Genes/métodos , Proteínas de Schizosaccharomyces pombe/genética , Schizosaccharomyces/genética , Sistemas CRISPR-Cas , Clonagem Molecular , Vetores Genéticos , Mutagênese Sítio-Dirigida , Mutação Puntual , Proteínas de Schizosaccharomyces pombe/química
9.
Reprod Med Biol ; 17(3): 325-328, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30013435

RESUMO

CASE: Approximately 3%-25% of cases of endometrial carcinoma (EC) or atypical endometrial hyperplasia (AH) occur in women aged <40 years and conservative treatment with high-dose medroxyprogesterone acetate (MPA) is administered to women who wish to preserve their fertility. Here is reported the pregnancy outcomes of patients with EC or AH who received MPA therapy at Tokushima University Hospital, Tokushima, Japan. The frequency of pregnancy and live births among the patients with EC or AH who received conservative treatment, followed by fertility treatment, were analyzed retrospectively. OUTCOME: Twelve patients underwent fertility examinations and received fertility treatment immediately after the completion of conservative treatment for EC or AH. One patient had the complication of severe diabetes and total embryo cryopreservation was performed before her diabetes was treated. Among the other 11 patients, 8 (72.7%) became pregnant at least once and 6 (54.5%) experienced at least 1 live birth. Three patients (25.0%) suffered disease recurrence during or after the infertility treatment and all of the recurrences occurred in the EC cohort. CONCLUSION: When patients with EC or AH wish to preserve their fertility, it is recommended that prompt and effective fertility treatment, including assisted reproductive technology, should be initiated just after conservative treatment because EC and AH exhibit relatively high recurrence rates among conservatively treated patients.

10.
Inflamm Bowel Dis ; 23(11): 2042-2047, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-29045261

RESUMO

BACKGROUND: Patients with inflammatory bowel disease (IBD) occasionally require central venous catheter (CVC) placement to support a therapeutic plan. Given that CVC can predispose patients to infection, this investigation was undertaken to assess the incidence, risk factors, and outcomes of CVC-related blood stream infection (CRBSI) in patients with IBD during routine clinical practice. METHODS: Data were compiled using retrospective chart reviews of 1367 patients treated at our IBD center between 2007 and 2012 during routine clinical practice. Among the 1367 patients, 314 who had received CVC placements were included. Patients with positive blood culture were considered as "definite" CRBSI, whereas "possible" CRBSI was defined as patients in whom fever alleviated within 48 hours post-CVC without any other infection. Patients' demographic variables including age, body mass index, serum albumin, duration of CVC placement, use of antibiotics, medications for IBD, and perioperative status between CRBSI and non-CRBSI subgroups were compared by applying a multivariate Poisson logistic regression model. RESULTS: Among the 314 patients with CVC placement, there were 83 CRBSI cases (26.4%). The average time to the onset of CRBSI was 22.5 days (range 4-105 days). The jugular vein access was found to be the most serious risk of CRBSI (risk ratio 2.041 versus subclavian vein). All patients with CRBSI fully recovered. CONCLUSIONS: In this investigation, regardless of the patients' demographic features including immunosuppressive therapy, up to 30% of febrile IBD patients with CVC showed CRBSI. It is believed that CVC placement per se is a risk of CRBSI in patients with IBD.


Assuntos
Bacteriemia/epidemiologia , Infecções Relacionadas a Cateter/epidemiologia , Cateteres Venosos Centrais/efeitos adversos , Doenças Inflamatórias Intestinais/terapia , Veias Jugulares/fisiopatologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Bacteriemia/etiologia , Criança , Feminino , Humanos , Incidência , Japão/epidemiologia , Tempo de Internação/estatística & dados numéricos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Estudos Retrospectivos , Fatores de Risco , Centros de Atenção Terciária , Adulto Jovem
11.
JMIR Res Protoc ; 6(4): e63, 2017 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-28428168

RESUMO

BACKGROUND: Diet and fluid restrictions that need continuous self-management are among the most difficult aspects of dialysis treatment. Smartphone applications may be useful for supporting self-management. OBJECTIVE: Our objective is to investigate the feasibility and usability of a novel smartphone-based self-management support system for dialysis patients. METHODS: We developed the Self-Management and Recording System for Dialysis (SMART-D), which supports self-monitoring of three mortality-related factors that can be modified by lifestyle: interdialytic weight gain and predialysis serum potassium and phosphorus concentrations. Data is displayed graphically, with all data evaluated automatically to determine whether they achieve the values suggested by the Japanese Society for Dialysis Therapy guidelines. In a pilot study, 9 dialysis patients used SMART-D system for 2 weeks. A total of 7 of them completed questionnaires rating their assessment of SMART-D's usability and their satisfaction with the system. In addition, the Kidney Disease Quality of Life scale was compared before and after the study period. RESULTS: All 9 participants were able to use SMART-D with no major problems. Completion rates for body weight, pre- and postdialysis weight, and serum potassium and phosphorus concentrations were, respectively, 89% (SD 23), 95% (SD 7), and 78% (SD 44). Of the 7 participants who completed the usability survey, all were motivated by the sense of security derived from using the system, and 6 of the 7 (86%) reported that using SMART-D helped improve their lifestyle and self-management. CONCLUSIONS: Using SMART-D was feasible, and the system was well regarded by patients. Further study with larger scale cohorts and longer study and follow-up periods is needed to evaluate the effects of SMART-D on clinical outcomes and quality of life.

13.
Chem Pharm Bull (Tokyo) ; 63(1): 13-7, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25743189

RESUMO

Layered double hydroxides (LDHs) have been used commercially as antacids, to stabilize drugs, to allow the controlled release of incorporated drugs, and to act as drug carriers to reduce drug accumulation within the body. Several types of LDH were investigated: nitrate type (LDH-NO3); chloride type (LDH-Cl); and carbonate type (LDH-CO3). Each type was added to an aqueous or methanol (MeOH) solution containing a drug (pravastatin or nateglinide). With pravastatin sodium, the interlayer distance expanded after reaction with LDH-NO3 and LDH-Cl in aqueous solution. In contrast, the interlayer distance of LDH-CO3 increased in methanol with nateglinide. Each drug was intercalated into the interlayer space of LDH by ion exchange. The hygroscopicity of the drug substances, complexes, and physical mixtures were determined at 70% relative humidity. Increases in weight (%) of the complexes were less than those of the physical mixtures, which demonstrates that hygroscopicity was reduced upon complexation with LDH due to the layer of LDH over the drugs.


Assuntos
Portadores de Fármacos/química , Hidróxidos/química , Molhabilidade , Carbonatos/química , Cloretos/química , Cicloexanos/química , Substâncias Intercalantes/química , Nateglinida , Nitratos/química , Fenilalanina/análogos & derivados , Fenilalanina/química , Pravastatina/química
14.
Clin Transpl ; 31: 35-42, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-28514566

RESUMO

Data collected by the United Network for Organ Sharing from all approved United States transplant programs were analyzed; the data included 20,290 adult diabetic patients who received primary pancreas transplants between October 1987 and December 2014. Simultaneous pancreas-kidney (SPK) transplantation has become the major therapeutic option for diabetes patients. The number of SPKs per year has not increased since 1999; it leveled off or decreased slightly each year. Recipients in the most recent period, 2010-2014, were more likely than recipients in any of the other periods to be non-white, older, male, to have had diabetes longer, to have higher body mass indices; and in this group there were more donor-recipient human leukocyte antigen mismatches. Donors in the 2010-2014 period were more likely to be younger and male and less likely to be white. Pancreas graft survival rates were highest in the 2010-2014 period (one-year graft survival 89.7%) vs. those for 1987-1989 (74.6%), 1990- 1994 (77.5%), 1995-1999 (82.9%), 2000-2004 (84.4%), and 2005-2009 (85.5%); the five-year rates were 72.7% for 2010-14 vs. 60.0%, 64.3%, 69.0%, 70.9%, and 73.9% for the other periods, respectively. There was no decreased risk of graft failure for recent-era transplants compared with those of 1987-1989, except for those in 2005-2009. By year of transplant, the adjusted hazard ratios [with 95% confidence intervals (CI)] for overall loss of grafts surviving over one year in eras 1990-1994, 1995-1999, 2000-2004, 2005-2009, and 2010-2014 were, respectively, 0.85 (CI 0.66-1.09), 0.85 (CI 0.66- 1.09), 0.87 (CI 0.67-1.13), 0.71 (CI 0.54-0.93), and 0.86 (CI 0.64-1.15). Chronic rejection caused 44.9% of graft losses between one and five years and 51.5% after five years. There is a need for a means to identify early markers of chronic rejection-and to control it-to improve long-term survival.

15.
Pharmaceutics ; 6(3): 436-46, 2014 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-25080007

RESUMO

The immobilization of potassium sorbate, potassium aspartate and sorbic acid in layered double hydroxide under solid condition was examined. By simply mixing two solids, immobilization of sorbate and aspartate in the interlayer space of nitrate-type layered double hydroxide, so called intercalation reaction, was achieved, and the uptakes, that is, the amount of immobilized salts and the interlayer distances of intercalation compounds were almost the same as those obtained in aqueous solution. However, no intercalation was achieved for sorbic acid. Although intercalation of sorbate and aspartate into chloride-type layered double hydroxide was possible, the uptakes for these intercalation compounds were lower than those obtained using nitrate-type layered double hydroxide. The intercalation under solid condition could be achieved to the same extent as for ion-exchange reaction in aqueous solution, and the reactivity was similar to that observed in aqueous solution. This method will enable the encapsulation of acidic drug in layered double hydroxide as nano level simply by mixing both solids.

16.
J Interferon Cytokine Res ; 33(6): 297-307, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23452206

RESUMO

Cigarette smoking is a major established environmental risk factor for rheumatoid arthritis (RA), and synoviocyte-derived proinflammatory cytokines are implicated in the pathogenesis of RA. We have reported that aryl hydrocarbon or cigarette smoke condensate (CSC) is able to upregulate the production of proinflammatory cytokines from an RA patient-derived synovial fibroblast cell line MH7A. In this study, we compared the effect of CSC on induction of interleukin-1ß (IL-1ß) from RA or osteoarthritis (OA) patient-derived synovial fibroblasts, and studied the mechanism of the effect of CSC. CSC induced IL-1ß mRNA from RA patient-derived synoviocytes and MH7A, but not from OA patient-derived synoviocytes. CSC induced the mRNA and both precursor and mature forms of IL-1ß, and caspase-1 activity in MH7A. The mechanism of CSC-induced IL-1ß mRNA expression was investigated in MH7A. Reporter gene analyses and promoter pull-down assay indicated that 3 novel NF-κB sites at -3771 to -3762 bp, -3105 to -3096 bp, and -2787 to -2778 bp in the promoter region of the IL-1ß gene, especially the far distal NF-κB site and NF-κB activation, are critical for the gene activation by CSC. CSC-induced NF-κB activation, IL-1ß promoter activity, IL-1ß mRNA upregulation, and CYP1A1 mRNA induction were all inhibited by an aryl hydrocarbon receptor (AhR) antagonist α-naphthoflavone. These results indicate that CSC induced IL-1ß production from RA patient-derived synoviocytes, but not OA patient-derived synoviocytes, through AhR-dependent NF-κB activation and novel NF-κB sites.


Assuntos
Artrite Reumatoide/metabolismo , Interleucina-1beta/biossíntese , NF-kappa B/metabolismo , Osteoartrite/genética , Receptores de Hidrocarboneto Arílico/metabolismo , Fumaça/efeitos adversos , Fumar/efeitos adversos , Membrana Sinovial/metabolismo , Artrite Reumatoide/genética , Artrite Reumatoide/patologia , Caspase 1/genética , Caspase 1/metabolismo , Linhagem Celular , Citocromo P-450 CYP1A1/genética , Citocromo P-450 CYP1A1/metabolismo , Fibroblastos/metabolismo , Humanos , Interleucina-1beta/genética , Interleucina-1beta/metabolismo , NF-kappa B/genética , Osteoartrite/metabolismo , Regiões Promotoras Genéticas/genética , RNA Mensageiro/genética , Receptores de Hidrocarboneto Arílico/genética , Membrana Sinovial/patologia , Nicotiana/química , Ativação Transcricional , Regulação para Cima
17.
Genes Dev ; 26(16): 1811-24, 2012 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-22895252

RESUMO

In fission yeast, siRNA is generated from pericentromeric noncoding RNA by the RNAi machinery. siRNA synthesis and heterochromatin formation are interdependent, forming a self-reinforcing loop on chromatin. In this system, siRNA is amplified by the RNA-dependent RNA polymerase complex (RDRC) and the endoribonuclease Dcr1, which synthesizes dsRNA and processes the dsRNA, respectively. The amplification is essential for stable heterochromatin formation. Here, a novel gene, dsh1(+) (defect of the gene silencing at centromeric heterochromatin), is identified as an essential component of RNAi-directed heterochromatin assembly. Loss of dsh1(+) abolishes normal RNAi function and heterochromatic gene silencing at pericentromeres. Dsh1 interacts with Dcr1 and RDRC and couples the reactions of both proteins to the effective production of siRNA in vivo. Dsh1 binds to heterochromatin in the absence of RDRC, while RDRC requires Dsh1 for its chromatin-binding activity, suggesting that Dsh1 recruits RDRC to chromatin. Immunofluorescence analysis shows that Dsh1 forms foci at the nuclear periphery, and some Dsh1 foci colocalize with Dcr1 and RDRC. Dsh1 is required for the colocalization of Dcr1 and RDRC. Moreover, loss of the nuclear periphery localization of Dsh1 abolishes Dsh1 function. Taken together, these results suggest that Dsh1 assembles the RNAi machinery on heterochromatin and forms a perinuclear compartment for amplification of heterochromatic siRNA.


Assuntos
Cromatina/metabolismo , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Proteínas de Schizosaccharomyces pombe , Schizosaccharomyces , Endorribonucleases/metabolismo , Heterocromatina/metabolismo , Mutação , Ligação Proteica , Estrutura Terciária de Proteína , Transporte Proteico , Schizosaccharomyces/genética , Schizosaccharomyces/metabolismo , Proteínas de Schizosaccharomyces pombe/genética , Proteínas de Schizosaccharomyces pombe/metabolismo
18.
Mol Cell ; 47(2): 228-41, 2012 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-22727667

RESUMO

Centromeric heterochromatin assembly in fission yeast requires the RNAi pathway. Chp1, a chromodomain (CD) protein, forms the Ago1-containing RNA-induced transcriptional silencing (RITS) complex and recruits siRNA-bound RITS to methylated histone H3 lysine 9 (H3K9me) via its CD. Here, we show that the CD of Chp1 (Chp1-CD) possesses unique nucleic acid-binding activities that are essential for heterochromatic gene silencing. Detailed electrophoretic-mobility shift analyses demonstrated that Chp1 binds to RNA via the CD in addition to its central RNA-recognition motif. Interestingly, robust RNA- and DNA-binding activity of Chp1-CD was strongly enhanced when it was bound to H3K9me, which was revealed to involve a positively charged domain within the Chp1-CD by structural analyses. These results demonstrate a role for the CD that provides a link between RNA, DNA, and methylated histone tails to ensure heterochromatic gene silencing.


Assuntos
Proteínas de Ciclo Celular/genética , Inativação Gênica , Heterocromatina/química , Proteínas de Schizosaccharomyces pombe/genética , Schizosaccharomyces/metabolismo , Sequência de Aminoácidos , Proteínas Argonautas/metabolismo , Imunoprecipitação da Cromatina , DNA/química , Relação Dose-Resposta a Droga , Fatores de Iniciação em Eucariotos/metabolismo , Regulação Fúngica da Expressão Gênica , Cinética , Metilação , Dados de Sequência Molecular , Estrutura Terciária de Proteína , RNA/química , Homologia de Sequência de Aminoácidos
19.
Proc Natl Acad Sci U S A ; 109(16): 6159-64, 2012 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-22474355

RESUMO

In fission yeast, the RNAi pathway is required for centromeric heterochromatin assembly. siRNAs derived from centromeric transcripts are incorporated into the RNA-induced transcriptional silencing (RITS) complex and direct it to nascent homologous transcripts. The RNA-induced transcriptional silencing-bound nascent transcripts further recruit the RNA-directed RNA polymerase complex (RDRC) to promote dsRNA synthesis and siRNA production. Heterochromatin coated with Swi6/Heterochromain Protein 1 is then formed following recruitment of chromatin modification machinery. Swi6 is also required for the upstream production of siRNA, although the mechanism for this has remained obscure. Here, we demonstrate that Swi6 recruits RDRC to heterochromatin through Ers1, an RNAi factor intermediate. An ers1(+) mutant allele (ers1-C62) was identified in a genetic screen for mutants that alleviate centromeric silencing, and this phenotype was suppressed by overexpression of either the Hrr1 RDRC subunit or Clr4 histone H3-K9 methyltransferase. Ers1 physically interacts with Hrr1, and loss of Ers1 impairs RDRC centromeric localization. Although Ers1 failed to bind Clr4, a direct interaction with Swi6 was detected, and centromeric localization of Swi6 was enhanced by Clr4 overexpression in ers1-C62 cells. Consistent with this, deletion of swi6(+) reduced centromeric localization of Ers1 and RDRC. Moreover, tethering of Ers1 or Hrr1 to centromeric heterochromatin partially bypassed Swi6 function. These findings demonstrate an alternative mechanism for RDRC recruitment and explain the essential role of Swi6/Heterochromain Protein 1 in RNAi-directed heterochromatin assembly.


Assuntos
Proteínas Cromossômicas não Histona/metabolismo , Heterocromatina/metabolismo , Interferência de RNA/fisiologia , Proteínas de Schizosaccharomyces pombe/metabolismo , Western Blotting , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Centrômero/genética , Centrômero/metabolismo , Imunoprecipitação da Cromatina , Proteínas Cromossômicas não Histona/genética , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Heterocromatina/genética , Histona-Lisina N-Metiltransferase , Metiltransferases/genética , Metiltransferases/metabolismo , Microscopia de Fluorescência , Mutação , Ligação Proteica , RNA Fúngico/genética , RNA Fúngico/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , RNA Polimerase Dependente de RNA/metabolismo , Complexo de Inativação Induzido por RNA/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Schizosaccharomyces/genética , Schizosaccharomyces/metabolismo , Proteínas de Schizosaccharomyces pombe/genética , Transdução de Sinais
20.
Mol Biol Cell ; 23(9): 1728-41, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22419820

RESUMO

A disintegrin-like and metalloprotease with thrombospondin type I motif (ADAMTS9) is a member of the secreted metalloprotease family that is believed to digest extracellular matrix (ECM) proteins outside of cells. Its Caenorhabditis elegans orthologue, GON-1, is involved in ECM degradation and is required for gonad morphogenesis. ADAMTS9 and GON-1 have similar domain structures, and both have a unique C-terminal domain called the "GON domain," whose function remains unknown. Here we show that down-regulation of human ADAMTS9 and C. elegans GON-1 results in the inhibition of protein transport from the endoplasmic reticulum (ER) to the Golgi. This phenotype was rescued by the expression of the GON domain localizing in the ER in human cells and C. elegans. We propose a novel function of ADAMTS9 and GON-1 in the ER that promotes protein transport from the ER to the Golgi. This function is GON-domain dependent but protease activity independent.


Assuntos
Proteínas ADAM/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Retículo Endoplasmático/metabolismo , Complexo de Golgi/metabolismo , Metaloendopeptidases/metabolismo , Proteínas ADAM/genética , Proteína ADAMTS9 , Animais , Animais Geneticamente Modificados , Caenorhabditis elegans , Proteínas de Caenorhabditis elegans/genética , Linhagem Celular , Sequência Conservada , Células HEK293 , Humanos , Metaloendopeptidases/genética , Transporte Proteico
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...