Nucleosomes package eukaryotic DNA and are composed of four different histone proteins, designated H3, H4, H2A, H2B. Histone H3 has two main variants, H3.1 H3.3, which show genomic localization patterns in animals. We profiled H3.3 variants the genome plant Arabidopsis thaliana found that these shows broad similarity plants animals, along with some unique features. was enriched silent areas genome, including regions containing repressive chromatin modifications lysine 27 methylation, 9...

Cell size set by cell cycle regulation In the Arabidopsis meristem, sizes are regularized despite asymmetric divisions. D'Ario et al. describe a balanced regulatory system that controls duration of growth phase preceding DNA synthesis. KIP-related protein 4 (KRP4) inhibits progression to Because amount KRP4, which binds mitotic chromosomes, is titrated chromosomal DNA, daughter cells begin with similar amounts KRP4 possible Deviations adjusted as excess degraded and normalized. Science ,...

Abstract Organogenesis in plants is almost entirely a postembryonic process. This unique feature implies strict coupling of cell proliferation and differentiation, including division, arrest, cycle reactivation, endoreplication, differentiation. The plant retinoblastoma-related (RBR) protein modulates the activity E2F transcription factors to restrict proliferation. Arabidopsis contains single RBR gene, its loss function precludes gamete formation early development. To determine relevance...

Abstract In plants, lateral roots originate from pericycle founder cells that are specified at regular intervals along the main root. Here, we show Arabidopsis (Arabidopsis thaliana) SKP2B (for S-Phase Kinase-Associated Protein2B), an F-box protein, negatively regulates cell cycle and root formation as it represses meristematic divisions. According to its function, is expressed in cells, primordia apical meristem. We identified a novel motif promoter required for specific expression...

A coordinated transition from cell proliferation to differentiation is crucial for organogenesis. We found that extensive chromatin reorganization, shown here histone H3 proteins, characterizes population dynamics in the root developmental compartments. The canonical H3.1 protein, incorporated during S-phase, maintained at high levels cells dividing a rate but massively evicted undergoing their last cycle before exit differentiation. similar pattern was observed quadruple mutant...

Summary Root branching in plants relies on the de novo formation of lateral roots. These are initiated from founder cells, triggering new formative divisions that generate root primordia (LRP). The LRP size and shape depends balance between positive negative signals control cell proliferation. mechanisms controlling proliferation potential cells remains poorly understood. We found Arabidopsis thaliana MYB36, which have been previously shown to regulate genes required for Casparian strip...

Differentiation of specialized cell types requires precise cell-cycle control. Plant stomata are generated through asymmetric divisions a stem-cell-like precursor followed by single symmetric division that creates paired guard cells surrounding pore. The stomatal-lineage-specific transcription factor MUTE terminates the and commits to differentiation. However, role machineries in this transition remains unknown. We discover is slower than Arabidopsis. identify plant-specific cyclin-dependent...

The retinoblastoma (Rb) protein was identified as a human tumour suppressor that controls various stages of cell proliferation through the interaction with members E2F family transcription factors. It originally thought to be specific animals but plants contain homologues Rb, called RETINOBLASTOMA-RELATED (RBR). In fact, Rb–E2F module seems very early acquisition eukaryotes. activity RBR depends on phosphorylation certain amino acid residues, which in most cases are well conserved between...

Transposable elements (TEs) are major players in genome evolution. The effects of their movement vary from gene knockouts to more subtle such as changes expression. It has recently been shown that TEs may contain transcription factor binding sites (TFBSs), and it proposed they rewire new genes into existing transcriptional networks. However, little is known about the dynamics this process its effect on binding. Here we show have extensively amplified number sequences match E2F TFBS during...

Abscisic acid (ABA) is fundamental for plant development. Multiple factors have been identified that participate in the ABA signaling network, although a role of many proteins still await to be demonstrated. Here we investigated GEM (GL2 EXPRESSION MODULATOR), originally annotated as an ABA-responsive protein. contains GRAM domain, feature shared with other eight Arabidopsis which propose name GRE (GEM-RELATED) proteins. We found (i) expression responds ABA, (ii) its promoter ABRE sites...

Programmed cell death (PCD) is crucial for development and homeostasis of all multicellular organisms. In human cells, the double role extra-mitochondrial cytochrome c in triggering apoptosis inhibiting survival pathways well reported. plants, however, specific upon release from mitochondria remains part veiled yet stimuli do trigger translocation as well. Here, we identify an Arabidopsis thaliana 14-3-3ι isoform a cytosolic target inhibitor caspase-like activity. This finding establishes...

Plants produce new organs post-embryonically throughout their entire life cycle. This is due to stem cells present in the shoot and root apical meristems, SAM RAM, respectively. In SAM, are located central zone where they divide slowly. Stem cell daughters displaced laterally enter peripheral zone, mitotic activity increases lateral organ primordia formed. How spatial arrangement of these different domains initiated controlled during growth development, how sites determined not yet...

Tomato bushy stunt virus and its cell-to-cell movement protein (MP; P22) provide valuable tools to study trafficking of macromolecules through plants. This shows that wild-type P22 selected movement-defective amino acid substitution mutants were equivalent for biochemical features commonly associated with MPs (i.e. RNA binding, phosphorylation, membrane partitioning). generated the hypothesis their defect was caused by improper interaction between one or more host factors. To test this, used...

Establishing the embryonic body plan of multicellular organisms relies on precisely orchestrated cell divisions coupled with pattern formation, which, in animals, are regulated by Polycomb group (PcG) proteins. The conserved Repressive Complex 2 (PRC2) mediates H3K27 trimethylation and comes different flavors Arabidopsis. PRC2 catalytic subunit MEDEA is required for seed development; however, a role patterning has been dismissed. Here, we demonstrate that embryos derived from medea eggs...

Panicum mosaic virus (PMV) is a single‐stranded positive‐sense RNA in the family Tombusviridae . PMV genomic (gRNA) and subgenomic (sgRNA) are not capped or polyadenylated. We have determined that uses cap‐independent mechanism of translation. A 116‐nucleotide translational enhancer (TE) region on 3′‐untranslated both gRNA sgRNA has been identified. The TE required for efficient translation viral proteins vitro. For mutants with compromised TE, addition cap analog, transposition cis ‐active...