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1.
Opt Express ; 31(18): 29676-29694, 2023 Aug 28.
Article in English | MEDLINE | ID: mdl-37710763

ABSTRACT

Relighting a single low-light image is a crucial and challenging task. Previous works primarily focused on brightness enhancement but neglected the differences in light and shadow variations, which leads to unsatisfactory results. Herein, an illumination field reconstruction (IFR) algorithm is proposed to address this issue by leveraging physical mechanism guidance, physical-based supervision, and data-based modeling. Firstly, we derived the Illumination field modulation equation as a physical prior to guide the network design. Next, we constructed a physical-based dataset consisting of image sequences with diverse illumination levels as supervision. Finally, we proposed the IFR neural network (IFRNet) to model the relighting progress and reconstruct photorealistic images. Extensive experiments demonstrate the effectiveness of our method on both simulated and real-world datasets, showing its generalization ability in real-world scenarios, even training solely from simulation.

2.
Anal Cell Pathol (Amst) ; 2018: 9275685, 2018.
Article in English | MEDLINE | ID: mdl-30050750

ABSTRACT

Medulloblastoma is the most common malignant brain tumor of childhood, with great potential to metastasize. However, the mechanisms of how medulloblastoma develops and progresses remain to be elucidated. The present study assessed the role of long noncoding RNA LOXL1-AS1 (lncRNA LOXL1-AS1) in the cell proliferation and metastasis in human medulloblastoma. It was initially found that LOXL1-AS1 was significantly overexpressed in clinical medulloblastoma tissues compared with the adjacent noncancerous tissues. LOXL1-AS1 was also highly expressed in medulloblastoma at advanced stages and differentially expressed in a series of medulloblastoma cell lines. Knockdown of LOXL1-AS1 using shRNAs significantly inhibited cell viability and colony formation capacities in D283 and D341 cells. Moreover, the cell proportion in the S phase was significantly increased, while the cell proportion in the G2/M phase was decreased after knockdown of LOXL1-AS1 in D283 cells and D341 cells. Cell cycle arrest led to eventual cell apoptosis by LOXL1-AS1 knockdown. Moreover, in a xenograft model of human medulloblastoma, knockdown of LOXL1-AS1 significantly inhibited tumor growth and promoted tumor cell apoptosis. In addition, knockdown of LOXL1-AS1 inhibited cell migration and reversed epithelial-to-mesenchymal transition (EMT). Western blot analysis further revealed that knockdown of LOXL1-AS1 decreased the phosphorylated levels of PI3K and AKT without affecting their total protein levels. These results suggest that LncRNA LOXL1-AS1 promoted the proliferation and metastasis of medulloblastoma by activating the PI3K-AKT pathway, providing evidence that knockdown of LncRNA LOXL1-AS1 might be a potential therapeutic strategy against medulloblastoma.


Subject(s)
Medulloblastoma/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism , RNA, Long Noncoding/metabolism , Animals , Apoptosis/genetics , Apoptosis/physiology , Blotting, Western , Cell Cycle/genetics , Cell Cycle/physiology , Cell Line, Tumor , Cell Movement/genetics , Cell Movement/physiology , Cell Proliferation/genetics , Cell Proliferation/physiology , Cell Survival/genetics , Cell Survival/physiology , Epithelial-Mesenchymal Transition/genetics , Epithelial-Mesenchymal Transition/physiology , Gene Expression Regulation, Neoplastic/genetics , Gene Expression Regulation, Neoplastic/physiology , Humans , Male , Medulloblastoma/genetics , Mice , Mice, Inbred BALB C , Mice, Nude , RNA, Long Noncoding/genetics
3.
Med Sci Monit ; 22: 1250-7, 2016 Apr 14.
Article in English | MEDLINE | ID: mdl-27078001

ABSTRACT

BACKGROUND Plumbagin is a potent antioxidant with anti-inflammatory and anti-carcinogenic action. Myocardial ischemia/reperfusion injury results in organ damage through oxidative stress and inflammatory mechanisms. In this study, we analyzed the potential role of plumbagin against myocardial I/R injury in Wistar rats. MATERIAL AND METHODS Oxidative stress was measured through ROS, lipid peroxide content, and antioxidant enzyme activities. The expression of redox signaling and inflammatory proteins was analyzed through Western blotting. Inflammatory cytokine expressions were determined through ELISA. RESULTS Oxidative stress status was reduced by plumbagin by decreasing ROS and lipid peroxide levels in rats with myocardial I/R (MI/R) injury. Plumbagin regulated redox imbalance induced by I/R injury by modulating the transcription factors NF-κB and Nrf-2. Further, downstream targets of NF-κB (COX-2, iNOS) and Nrf-2 (HO-1, NQO1 and GST) expression were significantly downregulated by plumbagin treatment. Pro-inflammatory cytokine expressions were significantly abrogated by plumbagin treatment. CONCLUSIONS This study shows the protective role of plumbagin against myocardial I/R injury by regulating antioxidant and inflammatory mechanisms.


Subject(s)
Myocardial Reperfusion Injury/prevention & control , NF-E2-Related Factor 2/metabolism , Naphthoquinones/pharmacology , Animals , Anti-Inflammatory Agents/pharmacology , Anticarcinogenic Agents/pharmacology , Antioxidants/pharmacology , Apoptosis/drug effects , Lipid Peroxidation/drug effects , Male , Mice , Mice, Inbred C57BL , Myocardial Reperfusion Injury/metabolism , NF-kappa B/metabolism , Oxidative Stress/drug effects , Random Allocation , Rats , Rats, Wistar , Signal Transduction/drug effects
4.
BMC Cancer ; 13: 537, 2013 Nov 10.
Article in English | MEDLINE | ID: mdl-24209998

ABSTRACT

BACKGROUND: Triple Negative subset of (TN) Breast Cancers (BC), a close associate of the basal-like subtype (with limited discordance) is an aggressive form of the disease which convey unpredictable, and poor prognosis due to limited treatment options and lack of proven effective targeted therapies. METHODS: We conducted an expression study of 240 formalin-fixed, paraffin-embedded (FFPE) primary biopsies from two cohorts, including 130 TN tumors, to identify molecular mechanisms of TN disease. RESULTS: The annotation of differentially expressed genes in TN tumors contained an overrepresentation of canonical Wnt signaling components in our cohort and others. These observations were supported by upregulation of experimentally induced oncogenic Wnt/ß-catenin genes in TN tumors, recapitulated using targets induced by Wnt3A. A functional blockade of Wnt/ß-catenin pathway by either a pharmacological Wnt-antagonist, WntC59, sulidac sulfide, or ß-catenin (functional read out of Wnt/ß-catenin pathway) SiRNA mediated genetic manipulation demonstrated that a functional perturbation of the pathway is causal to the metastasis- associated phenotypes including fibronectin-directed migration, F-actin organization, and invasion in TNBC cells. A classifier, trained on microarray data from ß-catenin transfected mammary cells, identified a disproportionate number of TNBC breast tumors as compared to other breast cancer subtypes in a meta-analysis of 11 studies and 1,878 breast cancer patients, including the two cohorts published here. Patients identified by the Wnt/ß-catenin classifier had a greater risk of lung and brain, but not bone metastases. CONCLUSION: These data implicate transcriptional Wnt signaling as a hallmark of TNBC disease associated with specific metastatic pathways.


Subject(s)
Biomarkers, Tumor/genetics , Bone Neoplasms/secondary , Brain Neoplasms/secondary , Lung Neoplasms/secondary , Triple Negative Breast Neoplasms/pathology , Wnt Proteins/metabolism , beta Catenin/metabolism , Biomarkers, Tumor/metabolism , Blotting, Western , Bone Neoplasms/genetics , Bone Neoplasms/metabolism , Brain Neoplasms/genetics , Brain Neoplasms/metabolism , Cell Movement , Cell Proliferation , Cohort Studies , Female , Follow-Up Studies , Gene Expression Profiling , Gene Expression Regulation, Neoplastic , Humans , Immunoenzyme Techniques , Lung Neoplasms/genetics , Lung Neoplasms/metabolism , Neoplasm Recurrence, Local/genetics , Neoplasm Recurrence, Local/metabolism , Neoplasm Recurrence, Local/pathology , Neoplasm Staging , Oligonucleotide Array Sequence Analysis , Paraffin Embedding , Prognosis , RNA, Messenger/genetics , RNA, Small Interfering/genetics , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , Signal Transduction , Survival Rate , Triple Negative Breast Neoplasms/genetics , Triple Negative Breast Neoplasms/metabolism , Tumor Cells, Cultured , Wnt Proteins/genetics , beta Catenin/antagonists & inhibitors , beta Catenin/genetics
5.
J Natl Cancer Inst ; 104(6): 441-51, 2012 Mar 21.
Article in English | MEDLINE | ID: mdl-22395644

ABSTRACT

BACKGROUND: Adjuvant tamoxifen therapy is effective for postmenopausal women with endocrine-responsive breast cancer. Cytochrome P450 2D6 (CYP2D6) enzyme metabolizes tamoxifen to clinically active metabolites, and CYP2D6 polymorphisms may adversely affect tamoxifen efficacy. In this study, we investigated the clinical relevance of CYP2D6 polymorphisms. METHODS: We obtained tumor tissues and isolated DNA from 4861 of 8010 postmenopausal women with hormone receptor-positive breast cancer who enrolled in the randomized, phase III double-blind Breast International Group (BIG) 1-98 trial between March 1998 and May 2003 and received tamoxifen and/or letrozole treatment. Extracted DNA was used for genotyping nine CYP2D6 single-nucleotide polymorphisms using polymerase chain reaction-based methods. Genotype combinations were used to categorize CYP2D6 metabolism phenotypes as poor, intermediate, and extensive metabolizers (PM, IM, and EM, respectively; n = 4393 patients). Associations of CYP2D6 metabolism phenotypes with breast cancer-free interval (referred to as recurrence) and treatment-induced hot flushes according to randomized endocrine treatment and previous chemotherapy were assessed. Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). All statistical tests were two-sided. RESULTS: No association between CYP2D6 metabolism phenotypes and breast cancer-free interval was observed among patients who received tamoxifen monotherapy without previous chemotherapy (P = .35). PM or IM phenotype had a non-statistically significantly reduced risk of breast cancer recurrence compared with EM phenotype (PM or IM vs EM, HR of recurrence = 0.86, 95% CI = 0.60 to 1.24). CYP2D6 metabolism phenotype was associated with tamoxifen-induced hot flushes (P = .020). Both PM and IM phenotypes had an increased risk of tamoxifen-induced hot flushes compared with EM phenotype (PM vs EM, HR of hot flushes = 1.24, 95% CI = 0.96 to 1.59; IM vs EM, HR of hot flushes = 1.23, 95% CI = 1.05 to 1.43). CONCLUSIONS: CYP2D6 phenotypes of reduced enzyme activity were not associated with worse disease control but were associated with increased hot flushes, contrary to the hypothesis. The results of this study do not support using the presence or absence of hot flushes or the pharmacogenetic testing of CYP2D6 to determine whether to treat postmenopausal breast cancer patients with tamoxifen.


Subject(s)
Antineoplastic Agents, Hormonal/therapeutic use , Breast Neoplasms/drug therapy , Breast Neoplasms/enzymology , Cytochrome P-450 CYP2D6/genetics , Nitriles/therapeutic use , Polymorphism, Single Nucleotide , Postmenopause , Tamoxifen/therapeutic use , Triazoles/therapeutic use , Aged , Antineoplastic Agents, Hormonal/administration & dosage , Aromatase Inhibitors/therapeutic use , Breast Neoplasms/genetics , Disease-Free Survival , Drug Administration Schedule , Female , Genotype , Humans , International Cooperation , Kaplan-Meier Estimate , Letrozole , Middle Aged , Nitriles/administration & dosage , Polymerase Chain Reaction , Polymorphism, Genetic , Tamoxifen/administration & dosage , Treatment Outcome , Triazoles/administration & dosage
6.
Ann Epidemiol ; 21(11): 864-72, 2011 Nov.
Article in English | MEDLINE | ID: mdl-21684175

ABSTRACT

PURPOSE: Common polymorphisms in the N-acetyltransferase-2 (NAT2) metabolic enzyme determine slow or rapid acetylator phenotypes. We investigated the effects of alcohol, smoking, and caffeine on fecundability, and determined whether the effects were modified by NAT2. METHODS: Three NAT2 polymorphisms were genotyped in 319 women office workers participating in a prospective pregnancy study (1990-1994). Women were ages 20-41 and at risk for pregnancy. Discrete-time survival analysis was used to determine the effects of alcohol, smoking, and caffeine on fecundability and evaluate effect modification by NAT2. RESULTS: We followed 319 women (161 slow acetylators, 158 rapid) for an average of 8 menstrual cycles, resulting in 124 pregnancies. There was no effect of caffeine on fecundability. Drinking ≥1 alcoholic drink per day and current smoking were significantly associated with reduced fecundability, but only among slow acetylators (adjusted fecundability odds ratio [FOR] for smoking = 0.34; 95% confidence interval, 0.22-0.90; adjusted FOR for ≥1 drink per day = 0.20; 0.05-0.92). There was no effect among rapid acetylators. CONCLUSIONS: NAT2 status significantly modified the effects of alcohol and smoking on fecundability, emphasizing the importance of incorporating genetic and metabolic information in studies of reproductive health. Replication of this study is warranted.


Subject(s)
Alcohol Drinking/epidemiology , Arylamine N-Acetyltransferase/genetics , Caffeine/administration & dosage , Fertility/drug effects , Fertility/genetics , Smoking/epidemiology , Acetylation , Adult , Alcohol Drinking/adverse effects , Alcohol Drinking/genetics , Alcohol Drinking/metabolism , Arylamine N-Acetyltransferase/metabolism , Caffeine/adverse effects , Female , Humans , Polymorphism, Genetic , Pregnancy , Smoking/genetics , Smoking/metabolism , United States/epidemiology , Young Adult
7.
Pediatr Dev Pathol ; 14(5): 370-7, 2011.
Article in English | MEDLINE | ID: mdl-21585276

ABSTRACT

Histiocytoid cardiomyopathy (HC) is a rare but distinctive arrhythmogenic disorder characterized by incessant ventricular tachycardia, cardiomegaly, and often sudden death by age 2 years. The underlying genetic mechanism of HC has eluded researchers for decades. To further identify the potential molecular-genetic bases of HC, molecular analyses of HC hearts and hearts of age-matched controls were performed. Total RNA and genomic DNA were prepared from formalin-fixed, paraffin-embedded cardiac tissue from 12 cases of HC and 12 age-matched controls. To identify genes differentially expressed in HC, whole genome cDNA-mediated annealing, selection, extension, and ligation profiling was performed. TaqMan quantitative polymerase chain reaction confirmed changes in RNA expression. DNA copy number changes were measured by TaqMan copy number variant analysis. Analysis of differential gene expression in HC cases identified 2 significantly downregulated gene sets aligned sequentially along the genome. The 1st gene cluster consisted of genes S100A8 , S100A9 , and S100A12 at 1q21.3c, and the 2nd cluster consisted of genes IL1RL1 ( ST2 ), IL18R1 , and IL18RAP at 2q12.1a. Strong decreases in interleukin 33 expression were also observed. Decreases in copy number of the S100A genes were confirmed by TaqMan copy number variant assays. S100A genes are downstream of the p38-MAPK pathway that can be activated by interleukin 33 signaling. These data suggest a model in which the interleukin 33-IL1RL1/p38-MAPK/ S100A8-S100A9 axis is downregulated in HC cardiac tissue and provide several candidate genes on 1q21.3c and 2q12.1a for inherited mutations that may predispose individuals to HC.


Subject(s)
Cardiomyopathies/congenital , Gene Expression Regulation , Genome, Human/genetics , Genome-Wide Association Study/methods , Cardiomyopathies/genetics , Cardiomyopathies/metabolism , Cardiomyopathies/pathology , DNA/analysis , Down-Regulation/genetics , Electron Transport Complex III/deficiency , Female , Gene Expression Profiling , Humans , Infant , Infant, Newborn , Male , Myocardium/chemistry , Myocardium/metabolism , Myocardium/pathology , Purkinje Fibers/chemistry , Purkinje Fibers/metabolism , Purkinje Fibers/pathology , RNA/analysis , Registries
8.
Circ Cardiovasc Genet ; 2(6): 614-20, 2009 Dec.
Article in English | MEDLINE | ID: mdl-20031642

ABSTRACT

BACKGROUND: We explored the relationship of genetic variants of the serotonin transporter gene SLC6A4, a key regulator of the serotonergic neurotransmission, with both depressive symptoms and plasma interleukin-6 (IL-6) levels. METHODS AND RESULTS: We genotyped 20 polymorphisms in 360 male twins (mean age, 54 years) from the Vietnam Era Twin Registry. Current depressive symptoms were measured with the Beck Depression Inventory II. IL-6 was assessed using a commercially available ELISA kit. Genotype associations were analyzed using generalized estimating equations. To study how SLC6A4 genetic vulnerability influences the relationship between depressive symptoms and IL-6, bivariate models were constructed using structural equation modeling. Of the 20 polymorphisms examined, the effective number of independent tests was 6, and the threshold of significance after Bonferroni correction was 0.008. There were 6 single-nucleotide polymorphisms significantly associated with Beck Depression Inventory (P< or =0.008), including rs8071667, rs2020936, rs25528, rs6354, rs11080122, and rs8076005, and 1 single-nucleotide polymorphism was borderline associated (rs12150214, P=0.017). Of these 7 single-nucleotide polymorphisms, 3 were also significantly associated with IL-6 (P<0.008), including rs25528, rs6354, and rs8076005, and the other 4 were borderline associated (P=0.009 to 0.025). The subjects with 1 copy of the minor allele of these 7 single-nucleotide polymorphisms had higher Beck Depression Inventory scores and IL-6 levels. Further bivariate modeling revealed that approximately 10% of the correlation between Beck Depression Inventory and IL-6 could be explained by the SLC6A4 gene. CONCLUSIONS: Genetic vulnerability involving the SLC6A4 gene is significantly associated with both increased depressive symptoms and elevated IL-6 plasma levels. Common pathophysiological processes may link depression and inflammation, and implicate the serotonin pathway in neural-immune interactions.


Subject(s)
Depression/blood , Depression/genetics , Interleukin-6/blood , Serotonin Plasma Membrane Transport Proteins/genetics , Humans , Male , Middle Aged , Polymorphism, Single Nucleotide , Twins/genetics
9.
Cancer Epidemiol Biomarkers Prev ; 18(9): 2553-7, 2009 Sep.
Article in English | MEDLINE | ID: mdl-19723917

ABSTRACT

There is evidence that adipokines such as leptin and adiponectin may influence breast tumor development. We conducted a nested case-control study using women in the American Cancer Society Cancer Prevention Study II to examine the association between postmenopausal breast cancer and variability in the genes encoding leptin, the leptin receptor, adiponectin, adiponectin receptor 1, and adiponectin receptor 2. Using 648 cases and 659 controls, we found no statistically significant (P < 0.05) associations between breast cancer risk and any of the single nucleotide polymorphisms. Individual odds ratios ranged from 0.93 to 1.06. We found no evidence of effect modification by body mass index, adult weight gain, location of weight gain, or physical activity. Although we cannot rule out that these genes are involved in gene-gene or gene-environment interactions, our results suggest that individual single nucleotide polymorphisms in these genes do not substantially affect postmenopausal breast cancer risk.


Subject(s)
Breast Neoplasms/genetics , Leptin/genetics , Receptors, Adiponectin/genetics , Receptors, Leptin/genetics , Adiponectin/genetics , Aged , Case-Control Studies , Female , Genotype , Humans , Polymorphism, Single Nucleotide , Postmenopause/genetics , Risk Factors
10.
J Immunol ; 182(6): 3638-49, 2009 Mar 15.
Article in English | MEDLINE | ID: mdl-19265142

ABSTRACT

NK cells have been established as an important effector of innate immunity in a variety of viral infections. In HIV-1 infection in humans, alterations of NK cell function, frequency, and expression of various NK receptors have been reported to be associated with differential dynamics of disease progression. Expression of certain alleles of KIR3DL and KIR3DS receptors on NK cells was shown to correlate with levels of virus replication. In the SIV-infected rhesus macaque (RM) model of AIDS, several families of killer inhibitory Ig-related receptors (KIR receptors) corresponding to their human counterparts have been characterized, but only at the level of individual sequence variants. Here we define 14 different alleles of KIR3DL expressed among 38 SIV-infected RM, characterized by either high or low levels of SIV replication, by analyzing multiple sequences from individual animals and show an unequal distribution of certain alleles in these cohorts. High levels of SIV replication were associated with significant increases in KIR3DL mRNA levels in addition to decreases in both the frequency and function of NK cells in these animals. The higher frequency of inheritance of two KIR3DL alleles characterized by a single nucleotide polymorphism 159 H/Q was associated with RM that exhibited high plasma viral load. This data for the first time defines multiple alleles of KIR3DL in RM and shows an association between virus control, NK cell function and genetic polymorphisms of KIR receptors.


Subject(s)
Alleles , Killer Cells, Natural/immunology , Killer Cells, Natural/pathology , Polymorphism, Single Nucleotide/genetics , Receptors, KIR3DL1/genetics , Simian Acquired Immunodeficiency Syndrome/immunology , Simian Immunodeficiency Virus/immunology , Viral Load , Amino Acid Sequence , Animals , Clone Cells , Cohort Studies , Genetic Predisposition to Disease , Humans , K562 Cells , Killer Cells, Natural/virology , Lymphocyte Count , Macaca mulatta , Molecular Sequence Data , Risk Factors , Simian Acquired Immunodeficiency Syndrome/genetics , Simian Acquired Immunodeficiency Syndrome/pathology , Simian Acquired Immunodeficiency Syndrome/virology , Simian Immunodeficiency Virus/growth & development , Virus Replication/immunology
12.
Breast Cancer Res ; 10(4): R57, 2008.
Article in English | MEDLINE | ID: mdl-18611262

ABSTRACT

INTRODUCTION: Obesity has consistently been associated with postmenopausal breast cancer risk. Proteins that are secreted by adipose tissue or are involved in regulating body mass may play a role in breast tumor development. METHODS: We conducted a nested case-control study among postmenopausal women from the American Cancer Society Cancer Prevention Study II Nutrition Cohort to determine whether genes associated with obesity increase risk for breast cancer. Tagging single nucleotide polymorphisms (SNPs) were selected to capture common variation across seven candidate genes that encode adipose-related proteins: ADRB2, ADRB3, GHRL, HSD11B1, IRS1, IRS2, and SHC1. Thirty-nine SNPs were genotyped in 648 cases and 659 controls. Logistic regression models were used to examine the association between each tagging SNP and risk for breast cancer while adjusting for matching factors and potential confounders. We also examined whether these SNPs were associated with measures of adult adiposity. RESULTS: Two out of five tagging SNPs in HSD11B1 were associated with breast cancer (rs11807619, P = 0.006; rs932335, P = 0.0001). rs11807619 and rs932335 were highly correlated (r2 = 0.74) and, when modeled as a haplotype, only haplotypes containing the rs932335 C allele were associated with breast cancer. The rs932335 C allele was associated with a nearly twofold increased risk for breast cancer (odds ratio = 1.83, 95% confidence interval = 1.01-3.33 for C/C versus G/G). Three of the 11 SNPs for IRS2 were associated with breast cancer (rs4773082, P = 0.007; rs2289046, P = 0.016; rs754204, P = 0.03). When these three SNPs were examined as a haplotype, only the haplotype that included the G allele of rs2289046 was associated with breast cancer (odds ratio = 0.76, 95% confidence interval = 0.63-0.92 for TGC versus CAT). IRS2 rs2289046, rs754204, and rs12584136 were also associated with adult weight gain but only among cases. None of the other SNPs in any gene investigated were associated with breast cancer or adiposity. CONCLUSION: Our findings suggest that these tagging SNPs in HSD11B1 and IRS2 mark regions of the genome that may harbor risk alleles for breast cancer, and these associations are probably independent of adiposity.


Subject(s)
Breast Neoplasms/genetics , Genetic Variation , Ghrelin/genetics , Insulin Receptor Substrate Proteins/genetics , Obesity/complications , Receptors, Adrenergic, beta-2/genetics , Receptors, Adrenergic, beta-3/genetics , 11-beta-Hydroxysteroid Dehydrogenase Type 1/genetics , Adipose Tissue/metabolism , Breast Neoplasms/complications , Breast Neoplasms/diagnosis , Cohort Studies , Genotype , Humans , Obesity/diagnosis , Obesity/genetics , Polymorphism, Single Nucleotide , Risk
13.
Plant Physiol ; 146(4): 1663-72, 2008 Apr.
Article in English | MEDLINE | ID: mdl-18305206

ABSTRACT

The MADS-domain transcriptional regulator AGAMOUS-LIKE15 (AGL15) has been reported to enhance somatic embryo development when constitutively expressed. Here we report that loss-of-function mutants of AGL15, alone or when combined with a loss-of-function mutant of a closely related family member, AGL18, show decreased ability to produce somatic embryos. If constitutive expression of orthologs of AGL15 is able to enhance somatic embryo development in other species, thereby facilitating recovery of transgenic plants, then AGL15 may provide a valuable tool for crop improvement. To test this idea in soybean (Glycine max), a full-length cDNA encoding a putative ortholog of AGL15 was isolated from soybean somatic embryos. Subsequently, the corresponding genomic region of the gene was obtained. This gene, designated GmAGL15, encodes a protein with highest similarity to AGL15 from Arabidopsis (Arabidopsis thaliana) and Brassica napus that accumulates to its highest amount in embryos in these species. Like Arabidopsis and Brassica AGL15, GmAGL15 was preferentially expressed in developing embryos. When ectopically overexpressed the soybean protein was able to enhance somatic embryo development in soybean.


Subject(s)
Arabidopsis Proteins/physiology , Arabidopsis/enzymology , Glycine max/enzymology , MADS Domain Proteins/physiology , Seeds/growth & development , Amino Acid Sequence , Arabidopsis Proteins/chemistry , Arabidopsis Proteins/genetics , MADS Domain Proteins/chemistry , MADS Domain Proteins/genetics , Molecular Sequence Data , Plants, Genetically Modified , Reverse Transcriptase Polymerase Chain Reaction , Sequence Homology, Amino Acid
14.
Plant Physiol ; 133(2): 653-63, 2003 Oct.
Article in English | MEDLINE | ID: mdl-14512519

ABSTRACT

The MADS domain protein AGL15 (AGAMOUS-Like 15) has been found to preferentially accumulate in angiosperm tissues derived from double fertilization (i.e. the embryo, suspensor, and endosperm) and in apomictic, somatic, and microspore embryos. Localization to the nuclei supports a role in gene regulation during this phase of the life cycle. To test whether AGL15 is involved in the promotion and maintenance of embryo identity, the embryogenic potential of transgenic plants that constitutively express AGL15 was assessed. Expression of AGL15 was found to enhance production of secondary embryos from cultured zygotic embryos, and constitutive expression led to long-term maintenance of development in this mode. Ectopic accumulation of AGL15 also promoted somatic embryo formation after germination from the shoot apical meristem of seedlings in culture. These results indicate that AGL15 is involved in support of development in an embryonic mode.


Subject(s)
Arabidopsis/genetics , MADS Domain Proteins/genetics , Plant Proteins/genetics , Arabidopsis/growth & development , Cloning, Molecular , Gene Expression Regulation, Developmental , Gene Expression Regulation, Plant , Genes, Reporter , Glucuronidase/genetics , Glucuronidase/metabolism , Meristem/growth & development , Recombinant Proteins/metabolism , Zygote/physiology
15.
J Biol Chem ; 278(30): 28154-9, 2003 Jul 25.
Article in English | MEDLINE | ID: mdl-12743119

ABSTRACT

AGL15 (for AGAMOUS-like 15) is currently the only reported member of the plant MADS domain family of transcriptional regulators that preferentially accumulates during embryo development. Additionally, AGL15 is one of the more divergent members of the MADS domain family, including within the DNA-binding domain. Previous studies have shown that MADS domain proteins bind to DNA sequences with an overall consensus of CC(A/T)6GG (called a CArG motif). Nonetheless, different MADS domain proteins exhibit similar yet distinct binding site preferences that may be critical for differential gene regulation. To determine the consensus sequence preferentially bound by AGL15 in vitro, PCR-assisted binding site selection assays were performed. AGL15 was observed to prefer a CArG motif with a longer A/T-rich core and is to date the only plant MADS domain protein having such a preference. Next, the Arabidopsis genome data base was searched for genes containing AGL15 binding sites as candidates for direct regulation by AGL15. One gene, DTA4 (for Downstream Target of AGL15-4), was identified by this method, and then confirmed as a direct target of AGL15 in vivo.


Subject(s)
MADS Domain Proteins/chemistry , Plant Proteins/chemistry , Amino Acid Motifs , Arabidopsis/metabolism , Binding Sites , Genes, Reporter , MADS Domain Proteins/metabolism , Models, Genetic , Plant Proteins/metabolism , Protein Binding , Protein Structure, Tertiary , RNA/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Time Factors , Transfection
16.
Plant J ; 32(5): 831-43, 2002 Dec.
Article in English | MEDLINE | ID: mdl-12472697

ABSTRACT

AGAMOUS-like-15 (AGL15) is a member of the MADS-domain family of DNA-binding regulatory factors that accumulates preferentially in tissue developing in an embryonic mode. To better understand how AGL15 functions, we developed a chromatin immunoprecipitation (ChIP) approach to isolate genes regulated directly by AGL15. ChIP allows purification of in vivo protein-DNA complexes. The co-purified DNA is recovered and used to isolate the putatively regulated gene. Several tests must be performed to show that the putative downstream target gene is truly regulated by the DNA-binding protein. The DNA-binding regulatory protein must interact with cis regulatory elements. The downstream gene expression pattern should respond to the level of the trans-acting regulatory factor. The cis element should be able to confer regulation in response to the trans-acting factor. We describe, in this report, our ChIP protocol, and discuss in detail, tests to confirm regulation by AGL15 for two targets identified by ChIP. These targets are referred to as Downstream Target of AGL15 (DTA1 and DTA2). Expression of DTA1, which encodes a protein with high similarity to GA-2 oxidase-like proteins, is induced by AGL15. DTA2 encodes a novel protein and expression of this target is repressed by AGL15.


Subject(s)
Arabidopsis/genetics , Arabidopsis/metabolism , Chromatin/genetics , Chromatin/metabolism , Gene Expression Regulation, Plant , Genes, Plant/genetics , MADS Domain Proteins/metabolism , Plant Proteins/metabolism , Arabidopsis/embryology , Arabidopsis Proteins/genetics , DNA, Plant/genetics , DNA, Plant/metabolism , DNA-Binding Proteins/metabolism , Precipitin Tests , Promoter Regions, Genetic/genetics , Seeds/embryology , Seeds/genetics , Seeds/metabolism , Substrate Specificity
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