Boron (B) is essential for plant growth but toxic when present in excess. In the roots of Arabidopsis thaliana under B limitation, a boric acid channel, NIP5;1, and acid/borate exporter, BOR1, are required efficient uptake subsequent translocation into xylem, respectively. However, high-B conditions, BOR1 activity repressed through endocytic degradation, presumably to avoid toxicity. this study, we investigated localization GFP-tagged NIP5;1 expressed control their native promoters. Under...

Abstract Boron (B) in soil is taken up by roots through NIP5;1, a boric acid channel, and loaded into the xylem BOR1, borate exporter. Here, function of Arabidopsis thaliana NIP6;1, most similar gene to was studied. NIP6;1 facilitates rapid permeation across membrane but completely impermeable water. transcript accumulation elevated response B deprivation shoots not roots. promoter–β-glucuronidase predominantly expressed nodal regions shoots, especially phloem region vascular tissues. Three...

Arsenite [As(III)] is highly toxic to organisms, including plants. Very recently, transporters in rice responsible for As(III) transport have been described (Ma, J. F., Yamaji, N., Mitani, Xu, X. Y., Su, Y. H., McGrath, S. P., and Zhao, F. (2008) Proc. Natl. Acad. Sci. U. A. 105, 9931–9935), but little known about tolerance. In this study, three independent As(III)-tolerant mutants were isolated from ethyl methanesulfonate-mutagenized M2 seeds of Arabidopsis thaliana. All carried mutations...

M Tanaka, U Grossniklaus, W Herr, and N Hernandez Cold Spring Harbor Laboratory, New York 11724.

Upstream open reading frames (uORFs) are often translated ahead of the main ORF a gene and regulate expression, sometimes in condition-dependent manner, but such role for minimum uORF (hereafter referred to as AUG-stop) living organisms is currently unclear. Here, we show that AUG-stop plays an important boron (B)-dependent regulation NIP5;1, encoding boric acid channel required normal growth under low B conditions Arabidopsis thaliana. High enhanced ribosome stalling at AUG-stop, which was...

Boron is an essential micronutrient for higher plants. deficiency important agricultural issue because it results in loss of yield quality and/or quantity cereals and other crops. To understand boron transport mechanisms cereals, we characterized OsNIP3;1, a member the major intrinsic protein family rice (Oryza sativa L.), OsNIP3;1 most similar gene to Arabidopsis thaliana boric acid channel genes AtNIP5;1 AtNIP6;1. Yeast cells expressing imported more than control cells. GFP-tagged...

Several mice with generalized lymphadenopathy were found in the CBA/KlJms (CBA) colony maintained at our institute. A new mutant strain of that develop massive lymphoid hyperplasia 100% incidence within 5 mo after birth was established by crossing these diseased mice. Genetic studies on conducted F1, F2, and backcross populations from crosses between CBA (CBA-m) various inbred strains The results supported control a single autosomal recessive gene. Since C3H/He-gld/gld (C3H-gld),...

Abstract Boron (B) is an essential plant micronutrient that toxic at higher levels. NIP5;1 a boric acid channel required for B uptake and growth under deficiency. Accumulation of the transcript upregulated deficiency in Arabidopsis thaliana roots. To elucidate mechanism regulation, 5′ untranslated region (UTR) was tested its ability to confer B-dependent regulation using β-glucuronidase green fluorescent protein as reporters. This analysis showed UTR involved accumulation response...

Transcriptional regulation by the ubiquitous human POU homeo domain protein Oct-1 and related B-cell Oct-2 is a model for understanding how proteins that recognize same regulatory site elicit different programs of gene transcription. Here, we describe mechanism differential promoter activation whereby only Oct-1, through selective corecruitment with herpesvirus trans-activator VP16, acquires ability to stimulate transcription from TAATGARAT-containing responds neither nor alone. To measure...

Binding of transcriptional activators to a promoter is prerequisite process in activation. It well established that the efficiency activator binding determined by affinity direct interactions between DNA-binding domain an and its specific target sequences. However, I describe here augmented vivo effects two other determinants have not been generally appreciated: (i) number sites present (ii) potency activation domains activators. Multiple within can cooperatively recruit cognate factors...

Boron (B) is an essential micronutrient for plants. Efflux-type B transporters, BORs, have been identified in Arabidopsis thaliana and rice. Here we BOR1 genes encoding efflux from the hexaploid genome of wheat (Triticum aestivum L.). We cloned three closely related to OsBOR1 named them TaBOR1.1, TaBOR1.2 TaBOR1.3. All TaBOR1s showed activities when expressed tobacco BY-2 cells. TaBOR1-green fluorescent protein (GFP) fusion proteins were leaf cells localized plasma membrane. The transcript...

In eukaryotes, messenger RNA (mRNA) accumulation is regulated through the levels of transcription, processing, and degradation. Here, we uncover multi-level regulatory mechanism governing expression NIP5;1, a boron (B) diffusion facilitator in Arabidopsis. B-dependent NIP5;1 mRNA degradation triggered by ribosome stalling at an AUGUAA sequence its 5'-untranslated region. We showed that deletion ATGTAA also abolishes transcriptional downregulation, revealing dual role this both control. Small...

The B-cell POU homeodomain protein Oct-2 contains two transcriptional activation domains, one N terminal and the other C of central DNA-binding domain. synergistic action these domains makes a more potent activator mRNA promoters than related broadly expressed octamer motif-binding Oct-1, which an N-terminal but not C-terminal Oct-2-like Both promoter were delineated by truncation analysis: Q domain is 66-amino-acid region rich in glutamines, P 42-amino-acid prolines. synergized with each or...

We previously reported that ribosome stalling at AUG-stop sequences in the 5'-untranslated region plays a critical role regulating expression of Arabidopsis thaliana NIP5;1, which encodes boron uptake transporter, response to conditions media. This is triggered specifically by boric acid, but mechanisms are unknown. Although upstream open reading frames (uORFs) known many cases regulate translation through peptides encoded uORF, does not involve any peptide synthesis. The unique feature...

Abstract Boron (B) is an essential micronutrient for plants. B deficiency and toxicity are widespread agricultural problems worldwide. To maintain appropriate levels in tissues, plants require B‐sensing mechanisms to regulate its transport. In Arabidopsis thaliana , the boric channel NIP5;1, borate transporter BOR1, their homologs plasma membrane responsible efficient uptake translocation of when supply limited. Importantly, these transport systems downregulated under high‐B conditions at...

The POU domain activator Oct-2 contains an N-terminal glutamine-rich transcriptional activation domain. An 18-amino-acid segment (Q18III) from this region reconstituted a fully functional when tandemly reiterated and fused to either the or GAL4 DNA-binding A minimal likely requires three tandem Q18III segments, because one two segments displayed little activity, whereas five were active increasing activity with copy number. As natural domains, in our assay required second homologous...

Nutrient uptake by roots often involves substrate-dependent regulated nutrient transporters. For robust uptake, the system requires a regulatory circuit within cells and collective, coordinated behaviour across tissue. A paradigm for such systems is boron known its directional transport homeostasis, as essential plant growth but toxic at high concentrations. In Arabidopsis thaliana, occurs via diffusion facilitators (NIPs) exporters (BORs), each presenting distinct polarity. Intriguingly,...

Eddy current and deflection analysis of a thin-plate model in time-changing magnetic field is described. The solved as coupled problem which the induces eddy currents cause thin plate by Lorentz force. are performed an integro-differential method using vector potential structural finite element beam elements, respectively. formulations motional electromotive force for presented. In addition, applicability proposed verified cantilevered-beam model.< <ETX...