Altered metal distribution in the sr45-1 Arabidopsis mutant causes developmental defects.

The plant serine/arginine-rich (SR) splicing factor SR45 plays important roles in several biological processes, such as splicing, DNA methylation, innate immunity, glucose regulation, and abscisic acid signaling. A homozygous Arabidopsis sr45-1 null mutant is viable, but exhibits diverse phenotypic alterations, including delayed root development, late flowering, shorter siliques with fewer seeds, narrower leaves and petals, and unusual numbers of floral organs. Here, we report that the sr45-1 mutant presents an unexpected constitutive iron deficiency phenotype characterized by altered metal distribution in the plant.

ZRT-IRT-Like PROTEIN 6 expression perturbs local ion homeostasis in flowers and leads to anther indehiscence and male sterility.

Metallic micronutrients are essential throughout the plant life cycle. Maintaining metal homeostasis in plant tissues requires a highly complex and finely tuned network controlling metal uptake, transport, distribution and storage. Zinc and cadmium hyperaccumulation, such as observed in the model plant Arabidopsis halleri, represents an extreme evolution of this network.

Long-term acclimation to cadmium exposure reveals extensive phenotypic plasticity in Chlamydomonas.

Increasing industrial and anthropogenic activities are producing and releasing more and more pollutants in the environment. Among them, toxic metals are one of the major threats for human health and natural ecosystems. Because photosynthetic organisms play a critical role in primary productivity and pollution management, investigating their response to metal toxicity is of major interest.

Transcriptional regulation of ZIP genes is independent of local zinc status in Brachypodium shoots upon zinc deficiency and resupply.

The biological processes underlying zinc homeostasis are targets for genetic improvement of crops to counter human malnutrition. Detailed phenotyping, ionomic, RNA-Seq analyses and flux measurements with Zn isotope revealed whole-plant molecular events underlying zinc homeostasis upon varying zinc supply and during zinc resupply to starved Brachypodium distachyon (Brachypodium) plants. Although both zinc deficiency and excess hindered Brachypodium growth, accumulation of biomass and micronutrients into roots and shoots differed depending on zinc supply.

di-Cysteine Residues of the HMA4 C-Terminus Are Only Partially Required for Cadmium Transport.

Cadmium (Cd) is highly toxic to the environment and humans. Plants are capable of absorbing Cd from the soil and of transporting part of this Cd to their shoot tissues. In Arabidopsis, the plasma membrane Heavy Metal ATPase 4 (HMA4) transporter mediates Cd xylem loading for export to shoots, in addition to zinc (Zn).

The two copies of the zinc and cadmium ZIP6 transporter of Arabidopsis halleri have distinct effects on cadmium tolerance.

Plants have the ability to colonize highly diverse environments. The zinc and cadmium hyperaccumulator Arabidopsis halleri has adapted to establish populations on soils covering an extreme range of metal availabilities. The A.

Correction: Co-Evolution of Mitochondrial tRNA Import and Codon Usage Determines Translational Efficiency in the Green Alga Chlamydomonas.

[This corrects the article DOI: 10.1371/journal.pgen.

Intertwined metal homeostasis, oxidative and biotic stress responses in the Arabidopsis frd3 mutant.

FRD3 (FERRIC REDUCTASE DEFECTIVE 3) plays a major role in iron (Fe) and zinc (Zn) homeostasis in Arabidopsis. It transports citrate, which enables metal distribution in the plant. An frd3 mutant is dwarf and chlorotic and displays a constitutive Fe-deficiency response and strongly altered metal distribution in tissues.

Homology modeling and in vivo functional characterization of the zinc permeation pathway in a heavy metal P-type ATPase.

The P1B ATPase heavy metal ATPase 4 (HMA4) is responsible for zinc and cadmium translocation from roots to shoots in Arabidopsis thaliana. It couples ATP hydrolysis to cytosolic domain movements, enabling metal transport across the membrane. The detailed mechanism of metal permeation by HMA4 through the membrane remains elusive.

di-Cysteine motifs in the C-terminus of plant HMA4 proteins confer nanomolar affinity for zinc and are essential for HMA4 function in vivo.

The PIB ATPase heavy metal ATPase 4 (HMA4) has a central role in the zinc homeostasis network of Arabidopsis thaliana. This membrane protein loads metal from the pericycle cells into the xylem in roots, thereby allowing root to shoot metal translocation. Moreover, HMA4 is key for zinc hyperaccumulation as well as zinc and cadmium hypertolerance in the pseudometallophyte Arabidopsis halleri.

Adaptation to high zinc depends on distinct mechanisms in metallicolous populations of Arabidopsis halleri.

Zinc (Zn) hyperaccumulation and hypertolerance are highly variable traits in Arabidopsis halleri. Metallicolous populations have evolved from nearby nonmetallicolous populations in multiple independent adaptation events. To determine whether these events resulted in similar or divergent adaptive strategies to high soil Zn concentrations, we compared two A.

The tau positron-emission tomography tracer AV-1451 binds with similar affinities to tau fibrils and monoamine oxidases.

Background: Lilly/Avid's AV-1451 is one of the most advanced tau PET tracers in the clinic. Although results obtained in Alzheimer's disease patients are compelling, discrimination of tracer uptake in healthy individuals and patients with supranuclear palsy (PSP) is less clear as there is substantial overlap of signal in multiple brain regions. Moreover, accurate quantification of [ F]AV-1451 uptake in Alzheimer's disease may not be possible.

Number of inadvertent RNA targets for morpholino knockdown in Danio rerio is largely underestimated: evidence from the study of Ser/Arg-rich splicing factors.

Although the involvement of Ser/Arg-rich (SR) proteins in RNA metabolism is well documented, their role in vertebrate development remains elusive. We, therefore, elected to take advantage of the zebrafish model organism to study the SR genes' functions using the splicing morpholino (sMO) microinjection and the programmable site-specific nucleases. Consistent with previous research, we revealed discrepancies between the mutant and morphant phenotypes and we show that these inconsistencies may result from a large number of unsuspected inadvertent morpholino RNA targets.

Metal binding to the N-terminal cytoplasmic domain of the PIB ATPase HMA4 is required for metal transport in Arabidopsis.

PIB ATPases are metal cation pumps that transport metals across membranes. These proteins possess N- and C-terminal cytoplasmic extensions that contain Cys- and His-rich high affinity metal binding domains, which may be involved in metal sensing, metal ion selectivity and/or in regulation of the pump activity. The PIB ATPase HMA4 (Heavy Metal ATPase 4) plays a central role in metal homeostasis in Arabidopsis thaliana and has a key function in zinc and cadmium hypertolerance and hyperaccumulation in the extremophile plant species Arabidopsis halleri.

Dynamic Distribution and Interaction of the Arabidopsis SRSF1 Subfamily Splicing Factors.

Ser/Arg-rich (SR) proteins are essential nucleus-localized splicing factors. Our prior studies showed that Arabidopsis (Arabidopsis thaliana) RSZ22, a homolog of the human SRSF7 SR factor, exits the nucleus through two pathways, either dependent or independent on the XPO1 receptor. Here, we examined the expression profiles and shuttling dynamics of the Arabidopsis SRSF1 subfamily (SR30, SR34, SR34a, and SR34b) under control of their endogenous promoter in Arabidopsis and in transient expression assay.

Functional analysis of the three HMA4 copies of the metal hyperaccumulator Arabidopsis halleri.

In Arabidopsis halleri, the HMA4 gene has an essential function in Zn/Cd hypertolerance and hyperaccumulation by mediating root-to-shoot translocation of metals. Constitutive high expression of AhHMA4 results from a tandem triplication and cis-activation of the promoter of all three copies. The three AhHMA4 copies possess divergent promoter sequences, but highly conserved coding sequences, and display identical expression profiles in the root and shoot vascular system.

Zinc triggers a complex transcriptional and post-transcriptional regulation of the metal homeostasis gene FRD3 in Arabidopsis relatives.

In Arabidopsis thaliana, FRD3 (FERRIC CHELATE REDUCTASE DEFECTIVE 3) plays a central role in metal homeostasis. FRD3 is among a set of metal homeostasis genes that are constitutively highly expressed in roots and shoots of Arabidopsis halleri, a zinc hyperaccumulating and hypertolerant species. Here, we examined the regulation of FRD3 by zinc in both species to shed light on the evolutionary processes underlying the evolution of hyperaccumulation in A.

Hard selective sweep and ectopic gene conversion in a gene cluster affording environmental adaptation.

Among the rare colonizers of heavy-metal rich toxic soils, Arabidopsis halleri is a compelling model extremophile, physiologically distinct from its sister species A. lyrata, and A. thaliana.

Use of red autofluorescence for monitoring prodiginine biosynthesis.

Prodigiosin-like pigments or prodiginines (PdGs) are promising drugs owing to their reported antitumor, antibiotic, and immunosuppressive activities. These natural compounds are produced by several bacteria, including Streptomyces coelicolor and Serratia marcescens as most commonly studied models. The bright red color of these tripyrrole pigments made them excellent reporter molecules for studies aimed at understanding the molecular mechanisms that control secondary metabolite production in microorganisms.

RUNX3, EGR1 and SOX9B form a regulatory cascade required to modulate BMP-signaling during cranial cartilage development in zebrafish.

The cartilaginous elements forming the pharyngeal arches of the zebrafish derive from cranial neural crest cells. Their proper differentiation and patterning are regulated by reciprocal interactions between neural crest cells and surrounding endodermal, ectodermal and mesodermal tissues. In this study, we show that the endodermal factors Runx3 and Sox9b form a regulatory cascade with Egr1 resulting in transcriptional repression of the fsta gene, encoding a BMP antagonist, in pharyngeal endoderm.

Co-evolution of mitochondrial tRNA import and codon usage determines translational efficiency in the green alga Chlamydomonas.

Mitochondria from diverse phyla, including protozoa, fungi, higher plants, and humans, import tRNAs from the cytosol in order to ensure proper mitochondrial translation. Despite the broad occurrence of this process, our understanding of tRNA import mechanisms is fragmentary, and crucial questions about their regulation remain unanswered. In the unicellular green alga Chlamydomonas, a precise correlation was found between the mitochondrial codon usage and the nature and amount of imported tRNAs.

Extracellular sugar phosphates are assimilated by Streptomyces in a PhoP-dependent manner.

Filamentous microorganisms of the bacterial genus Streptomyces have a complex life cycle that includes physiological and morphological differentiations. It is now fairly well accepted that lysis of Streptomyces vegetative mycelium induced by programmed cell death (PCD) provides the required nutritive sources for the bacterium to erect spore-forming aerial hyphae. However, little is known regarding cellular compounds released during PCD and the contribution of these molecules to the feeding of surviving cells in order to allow them to reach the late stages of the developmental program.

The HMG-box transcription factor Sox4b is required for pituitary expression of gata2a and specification of thyrotrope and gonadotrope cells in zebrafish.

The pituitary is a complex gland comprising different cell types each secreting specific hormones. The extensive network of signaling molecules and transcription factors required for determination and terminal differentiation of specific cell types is still not fully understood. The SRY-like HMG-box (SOX) transcription factor Sox4 plays important roles in many developmental processes and has two homologs in zebrafish, Sox4a and Sox4b.