252 research outputs found

    IDENTIFICATION AND CHARACTERIZATION OF PROTEINS THAT INTERACT WITH AGAMOUS-LIKE 15 (AGL15), A MADS-DOMAIN TRANSCRIPTION FACTOR THAT PREFERENTIALLY ACCUMULATES IN THE PLANT EMBRYO

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    AGAMOUS-Like 15 (AGL15) encodes a MADS-domain transcription factor that is preferentially expressed in the plant embryo, and may function as a regulator in embryonic developmental programs. A number of direct downstream targets of AGL15 have been identified, and while some of these target genes are induced in response to AGL15, others are repressed. Additionally, direct target genes have been analyzed that exhibit strong association with AGL15 in vivo, yet in vitro, AGL15 binds only weakly. Taken together these data suggest that AGL15 may form heterodimers, or ternary complexes with other proteins, thus modulating the specificity and function of AGL15 in planta. Yeast two-hybrid screens were undertaken to identify novel proteins able to interact with AGL15, and a number of interesting and potentially biologically important AGL15-interacting partners are reported here. These include members of a histone deacetylase complex, a COLD SHOCK DOMAIN (CSD)-containing protein, a Khomology domain/CCCH type zinc finger containing protein, a bZIP transcription factor, a homeobox-leucine zipper protein, a LATERAL ORGAN BOUNDARIES (LOB) domain containing protein, and an Agenet domain containing protein. Interactions between AGL15 and other MADS domain factors that are expressed in embryonic tissue, including SEPALLATA 3 (SEP3) have also been indentified. The regions of AGL15 that mediate interactions with the aforementioned proteins were mapped, and the capacity of these proteins to interact with other plant MADS-domain proteins tested. It is reported herein that AGL15 interacts with members of the SWI-INDEPENDENT 3/HISTONE DEACETYLASE (SIN3/HDAC) complex, and that AGL15 target genes are also responsive to an AGL15 interacting protein that is also a member of this complex, SIN3 ASSOCIATED POLYPEPTIDE OF 18 KD (SAP18). AGL15 can repress transcription in vivo, and a region essential to this repressive function contains an LxLxL motif that is conserved among putative orthologs of AGL15. What is more, the aforementioned motif mediates the association of AGL15 with SAP18 in yeast two-hybrid assays, thus providing a possible mechanism for explaining how role AGL15 regulates gene expression via recruitment of a histone deacetylase complex

    Finding the Motivation, Time, Personal Techniques, and Confidence to Write

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    Extension personnel need to embrace the concept of producing scholarship in written form. However, many often encounter challenges, such as finding time to write and figuring out how to get started. Scheduling writing times during your peak performance periods, using techniques that include goal setting or timed intensive writing, and overcoming your fears about writing can improve your productivity. Take the challenge, and start today

    The impact of abnormal glucose tolerance and obesity on fetal growth

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    Factors linked with insulin resistance were examined for their association with large-for-gestational-age (LGA) infant birth weight and gestational diabetes. Study Design. Data came from a longitudinal cohort study of 2,305 subjects without overt diabetes, analyzed using multinomial logistic and linear regression. Results. High maternal BMI (OR = 1.53 (1.11, 2.12)), height (1.98 (1.62, 2.42)), antidepressant use (1.71 (1.20, 2.44)), pregnancy weight-gain exceeding 40 pounds (1.79 (1.25, 2.57)), and high blood sugar (2.68, (1.53, 5.27)) were all positively associated with LGA birth. Strikingly, the difference in risk from diagnosed and treated gestational diabetes compared to women with a single abnormal glucose tolerance test (but no diagnosis of gestational diabetes) was significant (OR = 0.65, p = 0.12 versus OR = 2.84, p \u3c 0.01). When weight/length ratio was used instead, different factors were found to be significant. BMI and pregnancy weight-gain were found to influence the development of gestational diabetes, through an additive interaction. Conclusions. High prepregnancy BM, height, antidepressant use, pregnancy weight-gain exceeding 40 pounds, and high blood sugar were associated with LGA birth, but not necessarily infant weight/length ratio. An additive interaction between BMI and pregnancy weight-gain influenced gestational diabetes development

    Partnering with patients to design a prehabilitation program for optimizing the patient experience through general surgery

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    The objective of this study was to explore patients’ experiences when preparing for and undergoing general surgery at a large tertiary hospital. Findings aimed to inform the development of a prehabilitation program to empower patients to optimize their recovery and enhance their experience of general surgery. A qualitative exploratory research approach was utilized. Patients (\u3e18 years) attending for elective general surgery between May and July 2018 were invited to participate. Four focus groups (n=18) and an interview were conducted to reach saturation. Deductive content analysis was used to map responses against theoretical determinants of health behavior change. Patients described their overall experience of general surgery as positive but provided key insights about the surgical journey that impacted their capability, opportunity and motivation to optimally engage and address their recovery. Interaction and information from health professionals, understanding expectations, timely access to treatment and support of family members greatly enhanced their experience. Lack of personalized exercise and nutrition prescriptions, access to shared patient experiences of the surgical journey and not being asked about personal goals were key inhibitors. Patients also expressed feelings of frustration and anxiety regarding hospital procedures, including repetitive gathering of information and poor communication across departments. Patients’ experiences of the surgical journey identified gaps that impacted their capability, opportunity and motivation to effectively prepare and rehabilitate, that could be addressed by a multimodal prehabilitation program. Intervention options at patient and policy level were identified for trial to enhance the patient experience of general surgery. Experience Framework This article is associated with the Patient, Family & Community Engagement lens of The Beryl Institute Experience Framework (https://www.theberylinstitute.org/ExperienceFramework). Access other PXJ articles related to this lens. Access other resources related to this lens

    Auxin-dependent control of a plasmodesmal regulator creates a negative feedback loop modulating lateral root emergence

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    © 2020, The Author(s). Lateral roots originate from initial cells deep within the main root and must emerge through several overlying layers. Lateral root emergence requires the outgrowth of the new primordium (LRP) to coincide with the timely separation of overlying root cells, a developmental program coordinated by the hormone auxin. Here, we report that in Arabidopsis thaliana roots, auxin controls the spatiotemporal expression of the plasmodesmal regulator PDLP5 in cells overlying LRP, creating a negative feedback loop. PDLP5, which functions to restrict the cell-to-cell movement of signals via plasmodesmata, is induced by auxin in cells overlying LRP in a progressive manner. PDLP5 localizes to plasmodesmata in these cells and negatively impacts organ emergence as well as overall root branching. We present a model, incorporating the spatiotemporal expression of PDLP5 in LRP-overlying cells into known auxin-regulated LRP-overlying cell separation pathways, and speculate how PDLP5 may function to negatively regulate the lateral root emergence process

    Regulation of L1 expression and retrotransposition by melatonin and its receptor: implications for cancer risk associated with light exposure at night.

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    Expression of long interspersed element-1 (L1) is upregulated in many human malignancies. L1 can introduce genomic instability via insertional mutagenesis and DNA double-strand breaks, both of which may promote cancer. Light exposure at night, a recently recognized carcinogen, is associated with an increased risk of cancer in shift workers. We report that melatonin receptor 1 inhibits mobilization of L1 in cultured cells through downregulation of L1 mRNA and ORF1 protein. The addition of melatonin receptor antagonists abolishes the MT1 effect on retrotransposition in a dose-dependent manner. Furthermore, melatonin-rich, but not melatonin-poor, human blood collected at different times during the circadian cycle suppresses endogenous L1 mRNA during in situ perfusion of tissue-isolated xenografts of human cancer. Supplementation of human blood with exogenous melatonin or melatonin receptor antagonist during the in situ perfusion establishes a receptor-mediated action of melatonin on L1 expression. Combined tissue culture and in vivo data support that environmental light exposure of the host regulates expression of L1 elements in tumors. Our data imply that light-induced suppression of melatonin production in shift workers may increase L1-induced genomic instability in their genomes and suggest a possible connection between L1 activity and increased incidence of cancer associated with circadian disruption

    Inference of the Arabidopsis Lateral Root Gene Regulatory Network Suggests a Bifurcation Mechanism That Defines Primordia Flanking and Central Zones

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    A large number of genes involved in lateral root (LR) organogenesis have been identified over the last decade using forward and reverse genetic approaches in Arabidopsis thaliana. Nevertheless, how these genes interact to form a LR regulatory network largely remains to be elucidated. In this study, we developed a time-delay correlation algorithm (TDCor) to infer the gene regulatory network (GRN) controlling LR primordium initiation and patterning in Arabidopsis from a time-series transcriptomic data set. The predicted network topology links the very early-activated genes involved in LR initiation to later expressed cell identity markers through a multistep genetic cascade exhibiting both positive and negative feedback loops. The predictions were tested for the key transcriptional regulator AUXIN RESPONSE FACTOR7 node, and over 70% of its targets were validated experimentally. Intriguingly, the predicted GRN revealed a mutual inhibition between the ARF7 and ARF5 modules that would control an early bifurcation between two cell fates. Analyses of the expression pattern of ARF7 and ARF5 targets suggest that this patterning mechanism controls flanking and central zone specification in Arabidopsis LR primordia

    Arabidopsis antibody resources for functional studies in plants

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    © 2020, The Author(s). Here we report creation of a unique and a very valuable resource for Plant Scientific community worldwide. In this era of post-genomics and modelling of multi-cellular systems using an integrative systems biology approach, better understanding of protein localization at sub-cellular, cellular and tissue levels is likely to result in better understanding of their function and role in cell and tissue dynamics, protein–protein interactions and protein regulatory networks. We have raised 94 antibodies against key Arabidopsis root proteins, using either small peptides or recombinant proteins. The success rate with the peptide antibodies was very low. We show that affinity purification of antibodies massively improved the detection rate. Of 70 protein antibodies, 38 (55%) antibodies could detect a signal with high confidence and 22 of these antibodies are of immunocytochemistry grade. The targets include key proteins involved in hormone synthesis, transport and perception, membrane trafficking related proteins and several sub cellular marker proteins. These antibodies are available from the Nottingham Arabidopsis Stock Centre

    BRCA1 Recruitment to Transcriptional Pause Sites Is Required for R-Loop-Driven DNA Damage Repair

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    The mechanisms contributing to transcription-associated genomic instability are both complex and incompletely understood. Although R-loops are normal transcriptional intermediates, they are also associated with genomic instability. Here, we show that BRCA1 is recruited to R-loops that form normally over a subset of transcription termination regions. There it mediates the recruitment of a specific, physiological binding partner, senataxin (SETX). Disruption of this complex led to R-loop-driven DNA damage at those loci as reflected by adjacent Îł-H2AX accumulation and ssDNA breaks within the untranscribed strand of relevant R-loop structures. Genome-wide analysis revealed widespread BRCA1 binding enrichment at R-loop-rich termination regions (TRs) of actively transcribed genes. Strikingly, within some of these genes in BRCA1 null breast tumors, there are specific insertion/deletion mutations located close to R-loop-mediated BRCA1 binding sites within TRs. Thus, BRCA1/SETX complexes support a DNA repair mechanism that addresses R-loop-based DNA damage at transcriptional pause sites
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