SciCombinator

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Journal: Seminars in cell & developmental biology

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Plant cells connected to adjacent cells with rigid cell wall cannot change their position, so that appropriate nuclear positioning according to nuclear movement is indispensable for cellular development involving unequal cell division. Sessile plants are severely affected by fluctuating environmental conditions, so that movement of organelles including nucleus is fundamental to accomplish physiological functions. The mechanisms of nuclear movement and their purposes studied recently with Arabidopsis thaliana, the model plants for genetics and molecular biology, and the nuclear behavior in fern gametophytes, an apical growing protonemal cell and a two-dimensional prothallus of Adiantum capillus-veneris, the model plants for cell biology and photobiology are described in this review.

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Milk lipids provide a large proportion of energy, nutrients, essential fatty acids, and signaling molecules for the newborns, the synthesis of which is a tightly controlled process. Dysregulated milk lipid production and composition may be detrimental to the growth, development, health and survival of the newborns. Many genetically modified animal models have contributed to our understanding of milk lipid regulation in the lactating mammary gland. In this review, we discuss recent advances in our knowledge of the mechanisms that control milk lipid biosynthesis and secretion during lactation, and how maternal genetic and dietary defects impact milk lipid composition and consequently offspring traits.

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Empirical studies suggest that psychiatric disorders result from a complex interplay between genetic and environmental factors. Most evidence for such gene-environment interaction (GxE) is based on single candidate gene studies conducted from a Diathesis-Stress perspective. Recognizing the short-comings of candidate gene studies, GxE research has begun to focus on genome-wide and polygenic approaches as well as drawing on different theoretical concepts underlying GxE, such as Differential Susceptibility. After reviewing evidence from candidate GxE studies and presenting alternative theoretical frameworks underpinning GxE research, more recent approaches and findings from whole genome approaches are presented. Finally, we suggest how future GxE studies may unpick the complex interplay between genes and environments in psychiatric disorders.

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Split gene architecture of most human genes requires removal of intervening sequences by mRNA splicing that occurs on large multiprotein complexes called spliceosomes. Mutations compromising several spliceosomal components have been recorded in degenerative syndromes and haematological neoplasia, thereby highlighting the importance of accurate splicing execution in homeostasis of assorted adult tissues. Moreover, insufficient splicing underlies defective development of craniofacial skeleton and upper extremities. This review summarizes recent advances in the understanding of splicing factor function deduced from cryo-EM structures. We combine these data with the characterization of splicing factors implicated in hereditary or somatic disorders, with a focus on potential functional consequences the mutations may elicit in spliceosome assembly and/or performance. Given aberrant splicing or perturbations in splicing efficiency substantially underpin disease pathogenesis, profound understanding of the mis-splicing principles may open new therapeutic vistas. In three major sections dedicated to retinal dystrophies, hereditary acrofacial syndromes, and haematological malignancies, we delineate the noticeable variety of conditions associated with dysfunctional splicing and accentuate recurrent patterns in splicing defects.

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MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression post-transcriptionally by fine-tuning mRNA levels and translation during development and in adult tissues. miRNAs are transcribed as parts of longer precursors that undergo multiple processing steps before the mature miRNAs reach their target mRNAs in the cytoplasm. In addition to Drosha/DGCR8 and Dicer that are the essential components of the miRNA processing pathway, a range of other RNA binding proteins have recently been implicated in miRNA biogenesis. Among these, several well-known splicing factors have emerged as regulators of distinct miRNAs. In this review, we examine the mechanisms by which splicing factors regulate miRNA biogenesis. As both splicing factors and miRNAs play central roles in human disease biology we discuss implications of the links between splicing factors and miRNAs in human disease.

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Early life adversity remains a significant risk factor for the development of a host of negative behavioural and pathological outcomes in adulthood long after the stressor is over. Recent evidence indicates that these lasting effects of ELS may occur via alterations in the epigenetic landscape. Here, we review the main findings of the effects of early life adversity on DNA methylation, histone post-translational modification, and non-coding RNAs in the context of psychiatric disease in animal models and human cohorts. We specifically explore how early life adversity alters epigenetic patterns in both a global manner, and in specific candidate genes that play a role in relevant systems such as the hypothalamic-pituitary-adrenal axis, as well as neurotransmitter and neuroendocrine signalling. We also discuss how individual factors, such as genetics, sex, and age, as well as the type, and timing of early life adversity, can create differential susceptibility and significantly moderate outcomes. Although challenges remain in deciphering the complexity of how the early environment interacts with individual factors to determine epigenetic patterns, as well as how to translate these mechanistic findings into clinically relevant populations, the reviewed literature sheds light on the potential of the field to identify effective interventions for vulnerable individuals.

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Approximately one-third of all eukaryotic proteins are delivered to their destination by trafficking within the endomembrane system. Such cargo proteins are incorporated into forming membrane vesicles on donor compartments and delivered to acceptor compartments by vesicle fusion. How cargo proteins are sorted into forming vesicles is still largely unknown. Here we review the roles of small GTPases of the ARF/SAR1 family, their regulators designated ARF guanine-nucleotide exchange factors (ARF-GEFs) and ARF GTPase-activating proteins (ARF-GAPs) as well as coat protein complexes during membrane vesicle formation. Although conserved across eukaryotes, these four functional groups of proteins display plant-specific modifications in composition, structure and function.

Concepts: Cell, Archaea, Eukaryote, Cytosol, Endoplasmic reticulum, Prokaryote, Membrane biology, Endomembrane system

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Mammalian spermatogenesis is a tightly coordinated process that gives rise to mature spermatozoa capable of fertilising an ovum during sexual reproduction. A population of stem and progenitor cells known as undifferentiated spermatogonia enables continual spermatogenesis throughout life. A complex transcriptional network that balances self-renewal of spermatogonia with their timely differentiation in order to maintain constant fertility regulates this process. Importantly, post-transcriptional regulation of gene expression plays a critical role in spermatogenesis, necessitated by the profound genetic and morphological changes that occur during meiosis and sperm maturation. Pre-mRNA splicing, mRNA export, maintenance of transcript stability and translation are key RNA processing steps that are regulated in the male germline to maintain coordinated gene expression. In this review, we examine these processes in the context of mammalian spermatogenesis and provide an overview of key mediators at each step.

Concepts: DNA, Gene, Genetics, Cell nucleus, Gene expression, Transcription, RNA, Sperm

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The grass inflorescence is striking not only for its beauty and diversity, but also for its developmental complexity. While models of inflorescence architecture have been proposed in both eudicots and grasses, these are inadequate to fully explain the complex branching events that occur during the development of the grass inflorescence. Key to understanding grass inflorescence architecture is the meristem determinacy/indeterminacy decision, which regulates the number of branching events that occur. Here we review what has been learned about meristem determinacy from grass mutants with defects in inflorescence development. A picture is emerging of a complex network of signaling molecules and meristem identity factors that interact to regulate inflorescence meristem activity, many of which have been modified during crop domestication directly affecting yield traits.

Concepts: Mathematics, Emergence, Complexity, Developmental psychology, Maize

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Root hairs result from the polar outgrowth of root epidermis cells in vascular plants. Root hair development processes are regulated by intrinsic genetic programs, which are flexibly modulated by environmental conditions, such as nutrient availability. Basic programs for root hair development were present in early land plants. Subsequently, some plants developed the ability to utilize root hairs for specific functions, in particular, for interactions with other organisms, such as legume-rhizobia and host plants-parasites interactions. In this review, we summarize the molecular regulation of root hair development and the modulation of root hairs under limited nutrient supply and during interactions with other organisms.

Concepts: DNA, Gene expression, Organism, Eukaryote, Plant, Water, Vascular plant, Root