Extensively Current Activity of Transposable Elements in Natural Rice Accessions Revealed by Singleton Insertions.

Active transposable elements (TEs) have drawn more attention as they continue to create new insertions and contribute to genetic diversity of the genome. However, only a few have been discovered in rice up to now, and their activities are mostly induced by artificial treatments (e.g., tissue culture, hybridization etc.) rather than under normal growth conditions. To systematically survey the current activity of TEs in natural rice accessions and identify rice accessions carrying highly active TEs, the transposon insertion polymorphisms (TIPs) profile was used to identify singleton insertions, which were unique to a single accession and represented the new insertion of TEs in the genome. As a result, 10,924 high-confidence singletons from 251 TE families were obtained, covering all investigated TE types. The number of singletons varied substantially among different superfamilies/families, perhaps reflecting distinct current activity. Particularly, eight TE families maintained potentially higher activity in 3,000 natural rice accessions. Sixty percent of rice accessions were detected to contain singletons, indicating the extensive activity of TEs in natural rice accessions. Thirty-five TE families exhibited potentially high activity in at least one rice accession, and the majority of them showed variable activity among different rice groups/subgroups. These naturally active TEs would be ideal candidates for elucidating the molecular mechanisms underlying the transposition and activation of TEs, as well as investigating the interactions between TEs and the host genome.

Active Fraction Combination From Liuwei Dihuang Decoction Improves Adult Hippocampal Neurogenesis and Neurogenic Microenvironment in Cranially Irradiated Mice.

Background: Cranial radiotherapy is clinically used in the treatment of brain tumours; however, the consequent cognitive and emotional dysfunctions seriously impair the life quality of patients. LW-AFC, an active fraction combination extracted from classical traditional Chinese medicine prescription Liuwei Dihuang decoction, can improve cognitive and emotional dysfunctions in many animal models; however, the protective effect of LW-AFC on cranial irradiation-induced cognitive and emotional dysfunctions has not been reported. Recent studies indicate that impairment of adult hippocampal neurogenesis (AHN) and alterations of the neurogenic microenvironment in the hippocampus constitute critical factors in cognitive and emotional dysfunctions following cranial irradiation. Here, our research further investigated the potential protective effects and mechanisms of LW-AFC on cranial irradiation-induced cognitive and emotional dysfunctions in mice. Methods: LW-AFC (1.6 g/kg) was intragastrically administered to mice for 14 days before cranial irradiation (7 Gy γ-ray). AHN was examined by quantifying the number of proliferative neural stem cells and immature neurons in the dorsal and ventral hippocampus. The contextual fear conditioning test, open field test, and tail suspension test were used to assess cognitive and emotional functions in mice. To detect the change of the neurogenic microenvironment, colorimetry and multiplex bead analysis were performed to measure the level of oxidative stress, neurotrophic and growth factors, and inflammation in the hippocampus. Results: LW-AFC exerted beneficial effects on the contextual fear memory, anxiety behaviour, and depression behaviour in irradiated mice. Moreover, LW-AFC increased the number of proliferative neural stem cells and immature neurons in the dorsal hippocampus, displaying a regional specificity of neurogenic response. For the neurogenic microenvironment, LW-AFC significantly increased the contents of superoxide dismutase, glutathione peroxidase, glutathione, and catalase and decreased the content of malondialdehyde in the hippocampus of irradiated mice, accompanied by the increase in brain-derived neurotrophic factor, insulin-like growth factor-1, and interleukin-4 content. Together, LW-AFC improved cognitive and emotional dysfunctions, promoted AHN preferentially in the dorsal hippocampus, and ameliorated disturbance in the neurogenic microenvironment in irradiated mice. Conclusion: LW-AFC ameliorates cranial irradiation-induced cognitive and emotional dysfunctions, and the underlying mechanisms are mediated by promoting AHN in the dorsal hippocampus and improving the neurogenic microenvironment. LW-AFC might be a promising therapeutic agent to treat cognitive and emotional dysfunctions in patients receiving cranial radiotherapy.

MiR529a controls plant height, tiller number, panicle architecture and grain size by regulating SPL target genes in rice (Oryza sativa L.).

Rice is one of the most important food crops in the world. Breeding high-yield, multi-resistant and high-quality varieties has always been the goal of rice breeding. Rice tiller, panicle architecture and grain size are the constituent factors of yield, which are regulated by both genetic and environmental factors, including miRNAs, transcription factors, and downstream target genes. Previous studies have shown that SPL (SQUAMOSA PROMOTER BINDING-LIKE) transcription factors can control rice tiller, panicle architecture and grain size, which were regulated by miR156, miR529 and miR535. In this study, we obtained miR529a target mimicry (miR529a-MIMIC) transgenic plants to investigate plant phenotypes, physiological and molecular characteristics together with miR529a overexpression (miR529a-OE) and wild type (WT) to explore the function of miR529a and its SPL target genes in rice. We found that OsSPL2, OsSPL17 and OsSPL18 at seedling stage were regulated by miR529a, but there had complicated mechanism to control plant height. OsSPL2, OsSPL16, OsSPL17 and SPL18 at tillering stage were regulated by miR529a to control plant height and tiller number. And panicle architecture and grain size were controlled by miR529a through altering the expression of all five target genes OsSPL2, OsSPL7, OsSPL14, OsSPL16, OsSPL17 and OsSPL18. Our study suggested that miR529a might control rice growth and development by regulating different SPL target genes at different stages, which could provide a new method to improve rice yield by regulating miR529a and its SPL target genes.

Role of the anterior agranular insular cortex in the modulation of fear and anxiety.

The insular cortex, anatomically close to amygdala, is also an integrative hub for sensory, emotional and cognitive function. Growing body of evidences suggest that alterations in insular structure and function have also been implicated in anxiety disorders. However, the reciprocal connections and precise subdivision of insular cortex involved in anxiety activities remains mechanistically unclear. In the present study, using anterograde and retrograde tracing methods, we verified that the anterior (AIa) but not posterior (AIp) agranular insular cortex is a major source of projections to the amygdala. Consistently, excitotoxic lesions only in AIa induced the anxiolytic behaviors and impaired fear memory. Using optogenetics methods, we found that selectively photoactivation of AIa GABAergic neurons remarkably promoted cued fear extinction and relieved anxiety in PSTD mice model. Finally, the participation of AIa in the storage of learned fear is also supported by the abolished LTP after fear conditioning and decreased the cued freezing using protein synthesis inhibitor immediately following training. Our results underscore the importance of AIa in fear and anxiety behavior and suggest that the AIa might share functions and interaction with amygdala in in anxiety related disorders.

Kainate receptor mediated presynaptic LTP in agranular insular cortex contributes to fear and anxiety in mice.

Anxiety disorders represent serious social problems worldwide. Recent neuroimaging studies have found that elevated activity and altered connectivity of the insular cortex might account for the negative emotional states in highly anxious individuals. However, the exact synaptic mechanisms of specific insular subregions have yet to be studied in detail. To assess the electrophysiological properties of agranular insular cortex (AIC) neurons, basic synaptic transmission was recorded and different protocols were used to induce presynaptic and postsynaptic long-term potentiation in mice with anxiety-related behaviors. The presynaptic membrane expression of kainate receptors (KARs) and pharmacologic manipulations were quantified to examine the role of Gluk1 subtype in anxiety-like behaviors. Fear conditioning occludes electrically induced postsynaptic-LTP in the AIC. Quantal analysis of LTP expression in this region revealed a significant presynaptic component reflected by an increase in the probability of transmitter release. A form of presynaptic-LTP that requires KARs has been characterized. Interestingly, a simple emotional anxiety stimulus resulted in selective occlusion of presynaptic-LTP, but not of postsynaptic-LTP. Finally, injecting GluK1-specific antagonists into the AIC reduced behavioral responses to fear or anxiety stimuli in the mouse. These findings suggest that activity-dependent synaptic plasticity takes place in the AIC due to exposure to fear or anxiety, and inhibiting the presynaptic KAR function may help to prevent or treat anxiety disorder.