© 2020 American Society of Plant Biologists. All rights reserved.Proliferating cells actively coordinate growth and cell division to ensure cell-size homeostasis; however, the underlying mechanism through which size is controlled is still poorly understood. Defect in a SUMO protease protein, SMT7, has been shown to reduce cell division number and increase cell size of the small-size mutant mat3-4, which contains a defective Chlamydomonas retinoblastoma tumor suppressor-related protein. Here we describe development of an in vitro SUMOylation system using Chlamydomonas components and use it to provide evidence that SMT7 is a bona fide SUMO protease. We further demonstrate that the SUMO protease activity is required for supernumerous mitotic divisions of the mat3-4 cells. In addition, we identified ribosomal protein L30 (RpL30) as a prime SMT7 target and discovered that its SUMOylation is important to modulate cell division in mat3-4 cells. Loss of SMT7 caused elevated SUMOylated RpL30 levels. Importantly, overexpression of the translational fusion version of RpL30-SUMO4, which mimics elevation of the SUMOylated RpL30 protein in mat3-4 caused decrease in mitotic division and recapitulated the size-increasing phenotype of the smt7-1 mat3-4 cells. In summary, our studies reveal a novel mechanism through which a SUMO protease regulates cell division in the mat3-4 mutant of Chlamydomonas and provides yet another important example of the role that protein SUMOylation can play in regulating key cellular processes, including cell division. © 2020 American Society of Plant Biologists. All rights reserved.Transcriptome analysis by RNA sequencing (RNA-seq) has become an indispensable core research tool in modern plant biology. Virtually all RNA-seq studies provide a snapshot of the steady-state transcriptome, which contains valuable information about RNA populations at a given time, but lacks information about the dynamics of RNA synthesis and degradation. Only a few specialized sequencing techniques, such as global run-on sequencing (GRO-seq), have been applied in plants and provide information about RNA synthesis rates. Here, we demonstrate that RNA labeling with a modified, non-toxic uridine analog, 5-ethynyl uridine (5-EU), in Arabidopsis thaliana seedlings provides insight into the dynamic nature of a plant transcriptome. Pulse-labeling with 5-EU allowed the detection and analysis of nascent and unstable RNAs, of RNA processing intermediates generated by splicing, and of chloroplast RNAs. We also conducted pulse-chase experiments with 5-EU, which allowed us to determine RNA stabilities without the need for chemical inhibition of transcription using compounds such as actinomycin and cordycepin. Genome-wide analysis of RNA stabilities by 5-EU pulse-chase experiments revealed that this inhibitor-free RNA stability measurement results in RNA half-lives much shorter than those reported after chemical inhibition of transcription. In summary, our results show that the Arabidopsis nascent transcriptome contains unstable RNAs and RNA processing intermediates, and suggest that half-lives of plant RNAs are largely overestimated. Our results lay the ground for an easy and affordable nascent transcriptome analysis and inhibitor-free analysis of RNA stabilities in plants. © 2020 American Society of Plant Biologists. All rights reserved.During binocular viewing, visual inputs from the two eyes interact at the level of visual cortex. Here we studied binocular interactions in human visual cortex, including both sexes, using source-imaged Steady State Visual Evoked Potentials (SSVEP) over a wide range of relative contrast between two eyes. The regions of interest included areas V1, V3a, hV4, hMT+ and lateral occipital cortex (LOC). Dichoptic parallel grating stimuli in each eye modulated at distinct temporal frequencies allowed us to quantify spectral components associated with the individual stimuli from monocular inputs (self-terms) and responses due to interaction between the inputs from the two eyes (IM terms). Data with self-terms revealed an interocular suppression effect, in which the responses to the stimulus in one eye were reduced when a stimulus was presented simultaneously to the other eye. The suppression magnitude varied depending on visual area, and the relative contrast between the two eyes. Suppression was strongest in V1 and Vriate and extra-striate cortex. Furthermore, our model fits revealed different patterns of binocular interaction along the visual cortical hierarchy, particularly in terms of excitatory and suppressive contributions. Copyright © 2020 the authors.A recent proposal posits that humans might use the same neuronal machinery to support the representation of both spatial and non-spatial information, organising concepts and memories using spatial codes. This view predicts that the same neuronal coding schemes characterizing navigation in the physical space (tuned to distance and direction) should underlie navigation of abstract semantic spaces, even if they are categorical and labelled by symbols. We constructed an artificial semantic environment by parsing a bidimensional audiovisual object space into 4 labelled categories. Before and after a non-spatial symbolic categorization training, 25 adults (15 females) were presented with pseudorandom sequences of objects and words during a functional MRI session. We reasoned that subsequent presentations of stimuli (either objects or words) referring to different categories implied implicit movements in the novel semantic space, and that such movements subtended specific distances and directions. https://www.selleckchem.com/products/mycro-3.html Using whole-brain t humans use the same neural machinery to organize their memories as points of an internal map of experiences. We asked whether the same brain regions and neural codes supporting spatial navigation are recruited when humans use language to organize their knowledge of the world in categorical semantic representations. Using fMRI we show that the medial prefrontal cortex and the entorhinal portion of the hippocampal formation represent the distances and the movement directions between concepts of a novel audiovisual semantic space, and that it was possible to reconstruct, from neural data, their relationships in memory. Copyright © 2020 the authors.