The <i>Medicago</i> CDKC;1‐CYCLINT;1 kinase complex phosphorylates the carboxy‐terminal domain of RNA polymerase II and promotes transcription

Fülöp, Katalin; Pettkó‐Szandtner, Aladár; Magyar, Zoltán; Miskolczi, Pál; Kondorosi, Éva; Dudits, Dénes; Bako, L.

doi:10.1111/j.1365-313x.2005.02421.x

Cited by 62 publications

(34 citation statements)

References 66 publications

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“…In contrast with a previous report (Shimotohno et al, 2004), our data demonstrate that CDKD;1, a third member of the CDKD family, is also an active kinase and, similarly to CDKD;2 and CDKD;3, phosphorylates all Ser residues of Arabidopsis RNAPII CTD. In the cdkd double and d123* triple mutants, reduction of the CTD S 2 P mark during seedling development showed slower kinetics compared with the depletion of S 5 P, suggesting a possible involvement of other S 2 -specific CTD kinases, including candidate CDKC homologs of Ctk1/CDK9 (Fülöp et al, 2005;Cui et al, 2007). Throughout seedling development, the S 2 P levels were nonetheless lower in cdkf;1 compared with the cdkd mutants, suggesting that CDKF;1 is probably also required for maintenance of the CDKDindependent CTD S 2 -kinase activity.…”

Section: Cdkds Are Major Ctd S 5 -Kinases Implicated In 59-capping Ofmentioning

confidence: 99%

CDKF;1 and CDKD Protein Kinases Regulate Phosphorylation of Serine Residues in the C-Terminal Domain of Arabidopsis RNA Polymerase II

et al. 2012

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Phosphorylation of conserved Y 1 S 2 P 3 T 4 S 5 P 6 S 7 repeats in the C-terminal domain of largest subunit of RNA polymerase II (RNAPII CTD) plays a central role in the regulation of transcription and cotranscriptional RNA processing. Here, we show that Ser phosphorylation of Arabidopsis thaliana RNAPII CTD is governed by CYCLIN-DEPENDENT KINASE F;1 (CDKF;1), a unique plant-specific CTD S 7 -kinase. CDKF;1 is required for in vivo activation of functionally redundant CYCLIN-DEPENDENT KINASE Ds (CDKDs), which are major CTD S 5 -kinases that also phosphorylate in vitro the S 2 and S 7 CTD residues. Inactivation of CDKF;1 causes extreme dwarfism and sterility. Inhibition of CTD S 7 -phosphorylation in germinating cdkf;1 seedlings is accompanied by 39-polyadenylation defects of pre-microRNAs and transcripts encoding key regulators of small RNA biogenesis pathways. The cdkf;1 mutation also decreases the levels of both precursor and mature small RNAs without causing global downregulation of the protein-coding transcriptome and enhances the removal of introns that carry premicroRNA stem-loops. A triple cdkd knockout mutant is not viable, but a combination of null and weak cdkd;3 alleles in a triple cdkd123* mutant permits semidwarf growth. Germinating cdkd123* seedlings show reduced CTD S 5 -phosphorylation, accumulation of uncapped precursor microRNAs, and a parallel decrease in mature microRNA. During later development of cdkd123* seedlings, however, S 7 -phosphorylation and unprocessed small RNA levels decline similarly as in the cdkf;1 mutant. Taken together, cotranscriptional processing and stability of a set of small RNAs and transcripts involved in their biogenesis are sensitive to changes in the phosphorylation of RNAPII CTD by CDKF;1 and CDKDs.

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Section: Cdkds Are Major Ctd S 5 -Kinases Implicated In 59-capping Ofmentioning

confidence: 99%

CDKF;1 and CDKD Protein Kinases Regulate Phosphorylation of Serine Residues in the C-Terminal Domain of Arabidopsis RNA Polymerase II

et al. 2012

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“…Protoplast preparation and transformation were performed as described by Fülöp et al (2005). For each transformation, 30 µg each plasmid was mixed with 150 mL concentrated protoplast suspension and 450 mL polyethylene glycol solution [PEG 6000 25% (w/v), 0.45 M mannitol, and 0.1 M Ca(NO 3 ) 2 , pH 9].…”

Section: Transactivation Assays In Arabidopsis Protoplastsmentioning

confidence: 99%

MYB118 Represses Endosperm Maturation in Seeds of Arabidopsis

Barthole

Marchive

et al. 2014

The Plant Cell

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In the exalbuminous species Arabidopsis thaliana, seed maturation is accompanied by the deposition of oil and storage proteins and the reduction of the endosperm to one cell layer. Here, we consider reserve partitioning between embryo and endosperm compartments. The pattern of deposition, final amount, and composition of these reserves differ between the two compartments, with the embryo representing the principal storage tissue in mature seeds. Complex regulatory mechanisms are known to prevent activation of maturation-related programs during embryo morphogenesis and, later, during vegetative growth. Here, we describe a regulator that represses the expression of maturation-related genes during maturation within the endosperm. MYB118 is transcriptionally induced in the maturing endosperm, and seeds of myb118 mutants exhibit an endosperm-specific derepression of maturation-related genes associated with a partial relocation of storage compounds from the embryo to the endosperm. Moreover, MYB118 activates endosperm-induced genes through the recognition of TAACGG elements. These results demonstrate that the differential partitioning of reserves between the embryo and endosperm in exalbuminous Arabidopsis seeds does not only result from developmental programs that establish the embryo as the preponderant tissue within seeds. This differential partitioning is also regulated by MYB118, which regulates the biosynthesis of reserves at the spatial level during maturation.

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“…Fragments were introduced into pRT104 (N-terminal fusion with 3*Myc or 3*HA). For the co-IP assay, 5 µg of ECH fused to a Myc-tag and YIP4a or YIP4b fused to a HA tag were transiently expressed in Arabidopsis cell culture protoplasts (Fülöp et al, 2005). Immunocomplexes were captured on Protein G sepharose (GE Healthcare) as described by Cruz-Ramírez et al (2012).…”

Section: Co-ipmentioning

confidence: 99%

Trans-Golgi Network Localized ECHIDNA/Ypt Interacting Protein Complex Is Required for the Secretion of Cell Wall Polysaccharides inArabidopsis

et al. 2013

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The secretion of cell wall polysaccharides through the trans-Golgi network (TGN) is required for plant cell elongation. However, the components mediating the post-Golgi secretion of pectin and hemicellulose, the two major cell wall polysaccharides, are largely unknown. We identified evolutionarily conserved YPT/RAB GTPase Interacting Protein 4a (YIP4a) and YIP4b (formerly YIP2), which form a TGN-localized complex with ECHIDNA (ECH) in Arabidopsis thaliana. The localization of YIP4 and ECH proteins at the TGN is interdependent and influences the localization of VHA-a1 and SYP61, which are key components of the TGN. YIP4a and YIP4b act redundantly, and the yip4a yip4b double mutants have a cell elongation defect. Genetic, biochemical, and cell biological analyses demonstrate that the ECH/YIP4 complex plays a key role in TGN-mediated secretion of pectin and hemicellulose to the cell wall in dark-grown hypocotyls and in secretory cells of the seed coat. In keeping with these observations, Fourier transform infrared microspectroscopy analysis revealed that the ech and yip4a yip4b mutants exhibit changes in their cell wall composition. Overall, our results reveal a TGN subdomain defined by ECH/YIP4 that is required for the secretion of pectin and hemicellulose and distinguishes the role of the TGN in secretion from its roles in endocytic and vacuolar trafficking.

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The Medicago CDKC;1‐CYCLINT;1 kinase complex phosphorylates the carboxy‐terminal domain of RNA polymerase II and promotes transcription

Cited by 62 publications

References 66 publications

CDKF;1 and CDKD Protein Kinases Regulate Phosphorylation of Serine Residues in the C-Terminal Domain of Arabidopsis RNA Polymerase II

CDKF;1 and CDKD Protein Kinases Regulate Phosphorylation of Serine Residues in the C-Terminal Domain of Arabidopsis RNA Polymerase II

MYB118 Represses Endosperm Maturation in Seeds of Arabidopsis

Trans-Golgi Network Localized ECHIDNA/Ypt Interacting Protein Complex Is Required for the Secretion of Cell Wall Polysaccharides inArabidopsis

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