scholarly journals The Role of Light and Circadian Clock in Regulation of Leaf Senescence

2021 ◽  
Vol 12 ◽  
Author(s):  
Juhyeon Lee ◽  
Myeong Hoon Kang ◽  
Jung Yeon Kim ◽  
Pyung Ok Lim
Keyword(s):  
Circadian Clock ◽  
Leaf Senescence ◽  
Regulatory Networks ◽  
Molecular Mechanisms ◽  
Environmental Changes ◽  
Control Plant ◽  
Structural Features ◽  
Clock Period ◽  
Environmental Signals

Leaf senescence is an integrated response of the cells to develop age information and various environmental signals. Thus, some of the genes involved in the response to environmental changes are expected to regulate leaf senescence. Light acts not only as the primary source of energy for photosynthesis but also as an essential environmental cue that directly control plant growth and development including leaf senescence. The molecular mechanisms linking light signaling to leaf senescence have recently emerged, exploring the role of Phytochrome-Interacting Factors (PIFs) as a central player leading to diverse senescence responses, senescence-promoting gene regulatory networks (GRNs) involving PIFs, and structural features of transcription modules in GRNs. The circadian clock is an endogenous time-keeping system for the adaptation of organisms to changing environmental signals and coordinates developmental events throughout the life of the plant. Circadian rhythms can be reset by environmental signals, such as light-dark or temperature cycles, to match the environmental cycle. Research advances have led to the discovery of the role of core clock components as senescence regulators and their underlying signaling pathways, as well as the age-dependent shortening of the circadian clock period. These discoveries highlight the close relationship between the circadian system and leaf senescence. Key issues remain to be elucidated, including the effect of light on leaf senescence in relation to the circadian clock, and the identification of key molecules linking aging, light, and the circadian clock, and integration mechanisms of various senescence-affecting signals at the multi-regulation levels in dynamics point of view.

scholarly journals EYES ABSENT and TIMELESS integrate photoperiodic and temperature cues to regulate seasonal physiology in Drosophila

2020 ◽  
Author(s):  
Antoine Abrieux ◽  
Yongbo Xue ◽  
Yao Cai ◽  
Kyle M. Lewald ◽  
Hoang Nhu Nguyen ◽  
...  
Keyword(s):  
Circadian Clock ◽  
Molecular Mechanisms ◽  
Environmental Changes ◽  
Physiological Responses ◽  
Day Length ◽  
Short Photoperiod ◽  
Eyes Absent ◽  
Winter Conditions ◽  
Clock Protein

AbstractOrganisms possess photoperiodic timing mechanisms to anticipate variations in day length and temperature as the seasons progress. The nature of the molecular mechanisms interpreting and signaling these environmental changes to elicit downstream neuroendocrine and physiological responses are just starting to emerge. Here, we demonstrate that in Drosophila melanogaster, EYES ABSENT (EYA) acts as a seasonal sensor by interpreting photoperiodic and temperature changes to trigger appropriate physiological responses. We observed that tissue-specific genetic manipulation of eya expression is sufficient to disrupt the ability of flies to sense seasonal cues, thereby altering the extent of female reproductive dormancy. Specifically we observed that EYA proteins, which peak at night in short photoperiod and accumulate at higher levels in the cold, promote reproductive dormancy in female D. melanogaster. Furthermore, we provide evidence indicating that the role of EYA in photoperiodism and temperature sensing is aided by the stabilizing action of the light-sensitive circadian clock protein TIMELESS (TIM). We postulate that increased stability and level of TIM at night under short photoperiod together with the production of cold-induced and light-insensitive TIM isoforms facilitate EYA accumulation in winter conditions. This is supported by our observations that tim null mutants exhibit reduced incidence of reproductive dormancy in simulated winter conditions, while flies overexpressing tim show an increased incidence of reproductive dormancy even in long photoperiod.Significance StatementExtracting information on calendar time from seasonal changes in photoperiod and temperature is critical for organisms to maintain circannual cycles in physiology and behavior. Here we found that in flies, EYES ABSENT (EYA) protein act as a seasonal sensor by adjusting its abundance and circadian phase in response to changes in photoperiod and temperature. We show that the manipulation of EYA levels is sufficient to impair the ability of female Drosophila to regulate seasonal variation in reproductive dormancy. Finally, our results suggest an important role of the circadian clock protein TIMELESS (TIM) in modulating EYA level through its ability to measure night length, linking the circadian clock to seasonal timing.

scholarly journals Natural Compounds in Sex Hormone-Dependent Cancers: The Role of Triterpenes as Therapeutic Agents

2021 ◽  
Vol 11 ◽  
Author(s):  
Codruţa Şoica ◽  
Mirela Voicu ◽  
Roxana Ghiulai ◽  
Cristina Dehelean ◽  
Roxana Racoviceanu ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Therapeutic Potential ◽  
Treatment Options ◽  
Active Role ◽  
Structural Features ◽  
Sex Hormone ◽  
Ongoing Research ◽  
New Treatment ◽  
Highly Correlated

Sex hormone-dependent cancers currently contribute to the high number of cancer-related deaths worldwide. The study and elucidation of the molecular mechanisms underlying the progression of these tumors was a double-edged sword, leading to the expansion and development of new treatment options, with the cost of triggering more aggressive, therapy resistant relapses. The interaction of androgen, estrogen and progesterone hormones with specific receptors (AR, ER, PR) has emerged as a key player in the development and progression of breast, ovarian, prostate and endometrium cancers. Sex hormone-dependent cancers share a common and rather unique carcinogenesis mechanism involving the active role of endogenous and exogenous sex hormones to maintain high mitotic rates and increased cell proliferation thus increasing the probability of aberrant gene occurrence and accumulation highly correlated with abnormal cell division and the occurrence of malignant phenotypes. Cancer related hormone therapy has evolved, currently being associated with the blockade of other signaling pathways often associated with carcinogenesis and tumor progression in cancers, with promising results. However, despite the established developments, there are still several shortcomings to be addressed. Triterpenes are natural occurring secondary metabolites biosynthesized by various pathways starting from squalene cyclization. Due to their versatile therapeutic potential, including the extensively researched antiproliferative effect, these compounds are most definitely a cornerstone in the research and development of new natural/semisynthetic anticancer therapies. The present work thoroughly describes the ongoing research related to the antitumor activity of triterpenes in sex hormone-dependent cancers. Also, the current review highlights both the biological activity of various triterpenoid compounds and their featured mechanisms of action correlated with important chemical structural features.

scholarly journals First person – Kim Landry-Truchon and Nicolas Houde

2020 ◽  
Vol 13 (12) ◽  
pp. dmm048199
Keyword(s):  
Regulatory Networks ◽  
Molecular Mechanisms ◽  
Early Career ◽  
Mouse Lung ◽  
Pleuropulmonary Blastoma ◽  
First Person ◽  
Research Assistant ◽  
Lung Epithelium ◽  
Mouse Development

ABSTRACTFirst Person is a series of interviews with the first authors of a selection of papers published in Disease Models & Mechanisms, helping early-career researchers promote themselves alongside their papers. Kim Landry-Truchon is first author on ‘Deletion of Yy1 in mouse lung epithelium unveils molecular mechanisms governing pleuropulmonary blastoma pathogenesis’, published in DMM. Kim is a research assistant in the lab of Lucie Jeannotte at Centre de recherche du CHU de Québec-Université Laval, Québec, Canada, investigating organ development and the regulatory networks involved. Nicolas is a research assistant in the same lab, investigating the role of master transcription factors during mouse development.

scholarly journals Molecular Events Involved in Influenza A Virus-Induced Cell Death

2022 ◽  
Vol 12 ◽  
Author(s):  
Rui Gui ◽  
Quanjiao Chen
Keyword(s):  
Cell Death ◽  
Influenza A Virus ◽  
Influenza A ◽  
Regulatory Networks ◽  
Molecular Mechanisms ◽  
Tissue Destruction ◽  
Inflammatory Reactions ◽  
Molecular Events ◽  
Host Death

Viral infection usually leads to cell death. Moderate cell death is a protective innate immune response. By contrast, excessive, uncontrolled cell death causes tissue destruction, cytokine storm, or even host death. Thus, the struggle between the host and virus determines whether the host survives. Influenza A virus (IAV) infection in humans can lead to unbridled hyper-inflammatory reactions and cause serious illnesses and even death. A full understanding of the molecular mechanisms and regulatory networks through which IAVs induce cell death could facilitate the development of more effective antiviral treatments. In this review, we discuss current progress in research on cell death induced by IAV infection and evaluate the role of cell death in IAV replication and disease prognosis.

scholarly journals The Evolving Role of Ferroptosis in Breast Cancer: Translational Implications Present and Future

Cancers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 4576
Author(s):  
Hung-Yu Lin ◽  
Hui-Wen Ho ◽  
Yen-Hsiang Chang ◽  
Chun-Jui Wei ◽  
Pei-Yi Chu
Keyword(s):  
Breast Cancer ◽  
Cell Death ◽  
Regulatory Networks ◽  
Molecular Mechanisms ◽  
Drug Resistant ◽  
Therapeutic Targeting ◽  
The Past ◽  
Regulated Cell Death ◽  
Common Malignancy

Breast cancer (BC) is the most common malignancy among women worldwide. The discovery of regulated cell death processes has enabled advances in the treatment of BC. In the past decade, ferroptosis, a new form of iron-dependent regulated cell death caused by excessive lipid peroxidation has been implicated in the development and therapeutic responses of BC. Intriguingly, the induction of ferroptosis acts to suppress conventional therapy-resistant cells, and to potentiate the effects of immunotherapy. As such, pharmacological or genetic modulation targeting ferroptosis holds great potential for the treatment of drug-resistant cancers. In this review, we present a critical analysis of the current understanding of the molecular mechanisms and regulatory networks involved in ferroptosis, the potential physiological functions of ferroptosis in tumor suppression, its potential in therapeutic targeting, and explore recent advances in the development of therapeutic strategies for BC.

scholarly journals A WRKY transcription factor, TaWRKY42-B, facilitates initiation of leaf senescence by promoting jasmonic acid biosynthesis

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Ming-Ming Zhao ◽  
Xiao-Wen Zhang ◽  
Yong-Wei Liu ◽  
Ke Li ◽  
Qi Tan ◽  
...  
Keyword(s):  
Leaf Senescence ◽  
Expression Profiles ◽  
Functional Characterization ◽  
Wrky Transcription Factor ◽  
Positive Role ◽  
Environmental Signals ◽  
Source To Sink ◽  
Age Dependent ◽  
Functional Investigation

Abstract Background Leaf senescence comprises numerous cooperative events, integrates environmental signals with age-dependent developmental cues, and coordinates the multifaceted deterioration and source-to-sink allocation of nutrients. In crops, leaf senescence has long been regarded as an essential developmental stage for productivity and quality, whereas functional characterization of candidate genes involved in the regulation of leaf senescence has, thus far, been limited in wheat. Results In this study, we analyzed the expression profiles of 97 WRKY transcription factors (TFs) throughout the progression of leaf senescence in wheat and subsequently isolated a potential regulator of leaf senescence, TaWRKY42-B, for further functional investigation. By phenotypic and physiological analyses in TaWRKY42-B-overexpressing Arabidopsis plants and TaWRKY42-B-silenced wheat plants, we confirmed the positive role of TaWRKY42-B in the initiation of developmental and dark-induced leaf senescence. Furthermore, our results revealed that TaWRKY42-B promotes leaf senescence mainly by interacting with a JA biosynthesis gene, AtLOX3, and its ortholog, TaLOX3, which consequently contributes to the accumulation of JA content. In the present study, we also demonstrated that TaWRKY42-B was functionally conserved with AtWRKY53 in the initiation of age-dependent leaf senescence. Conclusion Our results revealed a novel positive regulator of leaf senescence, TaWRKY42-B, which mediates JA-related leaf senescence via activation of JA biosynthesis and has the potential to be a target gene for molecular breeding in wheat.

scholarly journals CREB mediates the C. elegans dauer polyphenism through direct and cell-autonomous regulation of TGF-β expression

PLoS Genetics ◽  
2021 ◽  
Vol 17 (7) ◽  
pp. e1009678
Author(s):  
JiSoo Park ◽  
Hyekyoung Oh ◽  
Do-Young Kim ◽  
YongJin Cheon ◽  
Yeon-Ji Park ◽  
...  
Keyword(s):  
Developmental Plasticity ◽  
Molecular Mechanisms ◽  
Environmental Changes ◽  
Marker Gene ◽  
Camp Response Element Binding ◽  
Camp Response Element ◽  
Developmental Programs ◽  
C Elegans ◽  
Element Binding Protein

Animals can adapt to dynamic environmental conditions by modulating their developmental programs. Understanding the genetic architecture and molecular mechanisms underlying developmental plasticity in response to changing environments is an important and emerging area of research. Here, we show a novel role of cAMP response element binding protein (CREB)-encoding crh-1 gene in developmental polyphenism of C. elegans. Under conditions that promote normal development in wild-type animals, crh-1 mutants inappropriately form transient pre-dauer (L2d) larva and express the L2d marker gene. L2d formation in crh-1 mutants is specifically induced by the ascaroside pheromone ascr#5 (asc-ωC3; C3), and crh-1 functions autonomously in the ascr#5-sensing ASI neurons to inhibit L2d formation. Moreover, we find that CRH-1 directly binds upstream of the daf-7 TGF-β locus and promotes its expression in the ASI neurons. Taken together, these results provide new insight into how animals alter their developmental programs in response to environmental changes.

scholarly journals Specificity of H2O2 signaling in leaf senescence: is the ratio of H2O2 contents in different cellular compartments sensed in Arabidopsis plants?

2022 ◽  
Vol 27 (1) ◽  
Author(s):  
Ulrike Zentgraf ◽  
Ana Gabriela Andrade-Galan ◽  
Stefan Bieker
Keyword(s):  
Hydrogen Peroxide ◽  
Leaf Senescence ◽  
Mineral Resources ◽  
Stress Signaling ◽  
Oxygen Species ◽  
Differential Impact ◽  
Environmental Signals ◽  
Complex Process ◽  
Cellular Compartments

AbstractLeaf senescence is an integral part of plant development and is driven by endogenous cues such as leaf or plant age. Developmental senescence aims to maximize the usage of carbon, nitrogen and mineral resources for growth and/or for the sake of the next generation. This requires efficient reallocation of the resources out of the senescing tissue into developing parts of the plant such as new leaves, fruits and seeds. However, premature senescence can be induced by severe and long-lasting biotic or abiotic stress conditions. It serves as an exit strategy to guarantee offspring in an unfavorable environment but is often combined with a trade-off in seed number and quality. In order to coordinate the very complex process of developmental senescence with environmental signals, highly organized networks and regulatory cues have to be in place. Reactive oxygen species, especially hydrogen peroxide (H2O2), are involved in senescence as well as in stress signaling. Here, we want to summarize the role of H2O2 as a signaling molecule in leaf senescence and shed more light on how specificity in signaling might be achieved. Altered hydrogen peroxide contents in specific compartments revealed a differential impact of H2O2 produced in different compartments. Arabidopsis lines with lower H2O2 levels in chloroplasts and cytoplasm point to the possibility that not the actual contents but the ratio between the two different compartments is sensed by the plant cells.

scholarly journals The Importance of Cytokinins during Reproductive Development in Arabidopsis and Beyond

2020 ◽  
Vol 21 (21) ◽  
pp. 8161
Author(s):  
Giada Callizaya Terceros ◽  
Francesca Resentini ◽  
Mara Cucinotta ◽  
Silvia Manrique ◽  
Lucia Colombo ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Functional Unit ◽  
Control Plant ◽  
Reproductive Development ◽  
Plant Reproduction ◽  
World Population ◽  
Plant Growth And Development ◽  
Seed Formation ◽  
Human Needs

Fertilization and seed formation are fundamental events in the life cycle of flowering plants. The seed is a functional unit whose main purpose is to propagate the plant. The first step in seed development is the formation of male and female gametophytes and subsequent steps culminate in successful fertilization. The detailed study of this process is highly relevant because it directly impacts human needs, such as protecting biodiversity and ensuring sustainable agriculture to feed the increasing world population. Cytokinins comprise a class of phytohormones that play many important roles during plant growth and development and in recent years, the role of this class of phytohormones during reproduction has become clear. Here, we review the role of cytokinins during ovule, pollen and seed formation at the genetic and molecular levels. The expansion of knowledge concerning the molecular mechanisms that control plant reproduction is extremely important to optimise seed production.

The Genetics of Evolutionary Novelties

2014 ◽  
Author(s):  
Günter P. Wagner
Keyword(s):  
Regulatory Networks ◽  
Molecular Mechanisms ◽  
Regulatory Elements ◽  
Complex Problem ◽  
Micro Rnas ◽  
Sex Comb ◽  
Gene Regulatory ◽  
Transcription Factor Proteins ◽  
Evolutionary Novelties

This chapter examines the molecular genetics of evolutionary novelties. In particular, it investigates which molecular mechanisms might be involved in the origination of novel gene regulatory networks (and, thus, character identity networks) and what these mechanisms imply for the origin of novel characters. The chapter begins with a discussion of the complex problem of the evolution of transcriptional regulation by focusing on the evolution of cis-regulatory elements (CREs) and the evolution of transcription factor proteins. It then asks whether novel pigment spots, such as the Drosophila wing spots, are novelties. It also explores an evolutionary novelty known as sex comb and the role of transposable elements in the origin of novel CREs. Finally, it considers the role of gene duplications, the evolution of micro-RNAs (miRNAs), and the possibility of a mechanistic difference between adaptation and innovation.

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