Structural Analysis of Arabidopsis thaliana Chromosome 5. I. Sequence Features of the 1.6 Mb Regions Covered by Twenty Physically Assigned P1 Clones

Sato, Shusei; Kotani, Hirokazu; Nakamura, Yasukazu; Kaneko, Takakazu; Asamizu, Erika; Fukami, Masanobu; Miyajima, Nobuyuki; Tabata, Satoshi

doi:10.1093/dnares/4.3.215

Cited by 64 publications

(32 citation statements)

References 17 publications

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“…Recombinant spinach TRX m (Schü rmann, 1995) at that concentration does not activate Arabidopsis DAHP synthase. Arabidopsis chloroplasts contain two TRX f isoforms (Sato et al, 1997). We have not yet shown which of these is the preferred reducing agent for DAHP synthase.…”

Section: Arabidopsis Dahp Synthase Requires Reduced Trx For Enzyme Acmentioning

confidence: 85%

Redox Regulation of Arabidopsis 3-Deoxy-d-arabino-Heptulosonate 7-Phosphate Synthase

2002

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The cDNA for 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase of Arabidopsis encodes a polypeptide with an amino-terminal signal sequence for plastid import. A cDNA fragment encoding the processed form of the enzyme was expressed in Escherichia coli. The resulting protein was purified to electrophoretic homogeneity. The enzyme requires Mn 2ϩ and reduced thioredoxin (TRX) for activity. Spinach (Spinacia oleracea) TRX f has an apparent dissociation constant for the enzyme of about 0.2 m. The corresponding constant for TRX m is orders of magnitude higher. In the absence of TRX, dithiothreitol partially activates the enzyme. Upon alkylation of the enzyme with iodoacetamide, the dependence on a reducing agent is lost. These results indicate that the first enzyme in the shikimate pathway of Arabidopsis appears to be regulated by the ferredoxin/TRX redox control of the chloroplast.

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Section: Arabidopsis Dahp Synthase Requires Reduced Trx For Enzyme Acmentioning

confidence: 85%

Redox Regulation of Arabidopsis 3-Deoxy-d-arabino-Heptulosonate 7-Phosphate Synthase

2002

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“…The complete AtCDK8 open reading frame (At5g63610) was amplified by PCR from the P1 clone MBK5 (24), cloned into the acceptor vector ST1-blue (Invitrogen), and verified by restriction digestion and DNA sequencing. AtCDK8 was then subcloned into yeast vector pAS64F2 (33) to obtain pAS-AtCDK8.…”

Section: Methodsmentioning

confidence: 99%

The Transcription Corepressor LEUNIG Interacts with the Histone Deacetylase HDA19 and Mediator Components MED14 (SWP) and CDK8 (HEN3) To Repress Transcription

González

Bowen

Carroll

et al. 2007

Molecular and Cellular Biology

128

101

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Transcription corepressors are general regulators controlling the expression of genes involved in multiple signaling pathways and developmental programs. Repression is mediated through mechanisms including the stabilization of a repressive chromatin structure over control regions and regulation of Mediator function inhibiting RNA polymerase II activity. Using whole-genome arrays we show that the Arabidopsis thaliana corepressor LEUNIG, a member of the GroTLE transcription corepressor family, regulates the expression of multiple targets in vivo. LEUNIG has a role in the regulation of genes involved in a number of different physiological processes including disease resistance, DNA damage response, and cell signaling. We demonstrate that repression of in vivo LEUNIG targets is achieved through histone deacetylase (HDAC)-dependent and -independent mechanisms. HDAC-dependent mechanisms involve direct interaction with HDA19, a class 1 HDAC, whereas an HDAC-independent repression activity involves interactions with the putative Arabidopsis Mediator components AtMED14/SWP and AtCDK8/HEN3. We suggest that changes in chromatin structure coupled with regulation of Mediator function are likely to be utilized by LEUNIG in the repression of gene transcription.The Arabidopsis thaliana gene LEUNIG (LUG) encodes a member of the conserved transcription corepressor family that includes Tup1 in yeast (Saccharomyces cerevisiae, Schizosaccharomyces pombe, and Candida albicans), Groucho (Gro) in Drosophila melanogaster, and Transducin-Like Enhancer of split (TLE) in mammals. These corepressors do not possess DNA binding motifs but repress a diverse number of target genes through targeted recruitment by site-specific DNA binding transcription factors. In Arabidopsis, LUG represses target gene transcription by interacting with DNA binding transcription factors through an adaptor protein, SEUSS (SEU), in a fashion analogous to the interaction between the yeast corepressor components Tup1 and Ssn6 (27,28). Once recruited, corepressors mediate repression through mechanisms that include stabilization of a repressive chromatin structure over control regions, inhibition of recruitment of the transcription machinery, and direct inhibition of the RNA polymerase II (Pol II) holoenzyme regulated through the associated Mediator complex. The LUG-SEU corepressor fails to repress transcription in the presence of a histone deacetylase (HDAC) inhibitor, suggesting that one mechanism of LUG repression is through the recruitment of HDAC activities (27). This observation is consistent with Arabidopsis plants that harbor mutations in HDAC-encoding genes displaying pleotropic phenotypes similar to those reported for lug mutants (31). In lug mutant flowers the class C floral homeotic MADS box gene AGAMOUS (AG) is expressed in all four floral whorls, resulting in the ectopic formation of carpels and stamens in the outer two whorls (19), suggesting that LUG is a repressor of AG. In addition, plants harboring mutations in LUG exhibit further pleotropic defects,...

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“…In Arabidopsis, the catalytic subunit of PP2 (PP2Ac) is encoded by at least five genes, each of which appears to be expressed in all tissues albeit at different levels (Ariñ o et al, 1993;Casamayor et al, 1994; Pérez-Callejó n et al, 1998). Re-garding the regulatory subunits, three genes encoding the A 65-kD subunit (Slabas et al, 1994), two genes encoding the B subunit (Rundle et al, 1995;Corum et al, 1996), and one gene encoding the BЈЈ regulatory subunit (Sato et al, 1997) have been identified. In the last years, four isoforms of the BЈ regulatory subunit of PP2A have been described in Arabidopsis, named AtBЈ␣, AtBЈ␤, AtBЈ␥ (Latorre et al, 1997), and AtBЈ␦ (Haynes et al, 1999).…”

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confidence: 99%

Molecular Characterization and Evolution of the Protein Phosphatase 2A B′ Regulatory Subunit Family in Plants

Terol

Bargues²,

Carrasco

et al. 2002

Plant Physiology

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Type 2A serine/threonine protein phosphatases (PP2A) are important components in the reversible protein phosphorylation events in plants and other organisms. PP2A proteins are oligomeric complexes constituted by a catalytic subunit and several regulatory subunits that modulate the activity of these phosphatases. The analysis of the complete genome of Arabidopsis allowed us to characterize four novel genes, AtBЈ⑀, AtBЈ, AtBЈ, and AtBЈ, belonging to the PP2A BЈ regulatory subunit family. Because four genes of this type had been described previously, this family is composed of eight members. Reverse transcriptase-polymerase chain reaction experiments showed that AtBЈ⑀ mRNAs are present in all Arabidopsis tissues analyzed, and their levels do not respond significantly to heat stress. Expressed sequence tags corresponding to AtBЈ, AtBЈ, and AtBЈ have been identified, indicating that the new genes are actively transcribed. The genomic organization of this family of PP2A regulatory subunits is reported, as well as its chromosomal location. An extensive survey of the family has been carried out in plants, characterizing BЈ subunits in a number of different species, and performing a phylogenetic study that included several BЈ regulatory proteins from animals. Our results indicate that the animal and plant proteins have evolved independently, that there is a relationship between the number of BЈ isoforms and the complexity of the organism, and that there are at least three main subfamilies of regulatory subunits in plants, which we have named ␣, , and .Reversible protein phosphorylation is widely accepted as a major mechanism for the control of biological processes in eukaryotic cells. In plants, reversible protein phosphorylation is involved in processes such as hormonal, pathogenic, or environmental stress responses (Mumby and Walter, 1993;Smith and Walker, 1993; Garbers et al., 1996;Schö ntal, 1998; Janssens and Goris, 2001). In this context, Ser/Thr protein phosphatases (PPs) are important regulatory components of many signal transduction pathways (Ingebritsen and Cohen, 1983a;Schö ntal, 1998). Several Ser/Thr phosphatases, grouped into different categories, have been identified in a variety of plant species. Specifically, homologs of the 1, 2A, and 2C types of animal PPs have been described in plants (Rodríguez, 1998; Lin et al., 1999; Meek et al., 1999). All these types of PPs are distinguished by their different sensitivity to inhibitors and their divalent cation requirements, and are structurally different (for review, see Mumby and Walter, 1993).Type 2A phosphatases (PP2A) are oligomeric enzymes with no obvious requirements for ions or cofactors, and are implicated in a variety of cellular processes (Mumby and Walter, 1993; Janssens and Goris, 2001). In general, the native forms of PP2A proteins exist as oligomeric complexes, constituted by a catalytic subunit (PP2Ac), and one or more regulatory subunits named A and B. Thus, PP2A proteins can be heterodimers, consisting of a PP2Ac catalytic subunit and a type A...

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Structural Analysis of Arabidopsis thaliana Chromosome 5. I. Sequence Features of the 1.6 Mb Regions Covered by Twenty Physically Assigned P1 Clones

Cited by 64 publications

References 17 publications

Redox Regulation of Arabidopsis 3-Deoxy-d-arabino-Heptulosonate 7-Phosphate Synthase

Redox Regulation of Arabidopsis 3-Deoxy-d-arabino-Heptulosonate 7-Phosphate Synthase

The Transcription Corepressor LEUNIG Interacts with the Histone Deacetylase HDA19 and Mediator Components MED14 (SWP) and CDK8 (HEN3) To Repress Transcription

Molecular Characterization and Evolution of the Protein Phosphatase 2A B′ Regulatory Subunit Family in Plants

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