<i>Arabidopsis thaliana </i><scp>IRX</scp>10 and two related proteins from psyllium and <i><scp>P</scp>hyscomitrella patens</i> are xylan xylosyltransferases

Jensen, Jacob Krüger; Johnson, Nathan; Wilkerson, Curtis G.

doi:10.1111/tpj.12641

Cited by 90 publications

(90 citation statements)

References 53 publications

(76 reference statements)

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“…Plant glycosyltransferases have been heterologously expressed mainly in eukaryotic cells for in vitro characterization (Faik et al, 2002;Cavalier and Keegstra, 2006;Jensen et al, 2014;Urbanowicz et al, 2014). Here, we expressed truncated versions of XXTs in prokaryotic cells, demonstrating that catalytic activity does not require the N terminus and transmembrane domains or glycosylation; however, glycosylation may improve protein folding and/or solubility.…”

Section: Discussionmentioning

confidence: 99%

Enzymatic Activity of Xyloglucan Xylosyltransferase 5

et al. 2016

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ORCID IDs: 0000-0002-5107-9009 (R.F.); 0000-0001-6938-6923 (O.A.Z.).Xyloglucan, the most abundant hemicellulosic component of the primary cell wall of flowering plants, is composed of a b-(1,4)-glucan backbone decorated with D-xylosyl residues. Three xyloglucan xylosyltransferases (XXTs) participate in xyloglucan biosynthesis in Arabidopsis (Arabidopsis thaliana). Two of these, XXT1 and XXT2, have been shown to be active in vitro, whereas the catalytic activity of XXT5 has yet to be demonstrated. By optimizing XXT2 expression in a prokaryotic system and in vitro activity assay conditions, we demonstrate that nonglycosylated XXT2 lacking its cytosolic amino-terminal and transmembrane domain displays high catalytic activity. Using this optimized procedure for the expression of XXT5, we report, to our knowledge for the first time, that recombinant XXT5 shows enzymatic activity in vitro, although at a significantly slower rate than XXT1 and XXT2. Kinetic analysis showed that XXT5 has a 7-fold higher K m and 9-fold lower k cat compared with XXT1 and XXT2. Activity assays using XXT5 in combination with XXT1 or XXT2 indicate that XXT5 is not specific for their products. In addition, mutagenesis experiments showed that the in vivo function and in vitro catalytic activity of XXT5 require the aspartate-serine-aspartate motif. These results demonstrate that XXT5 is a catalytically active xylosyltransferase involved in xylosylation of the xyloglucan backbone.

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Section: Discussionmentioning

confidence: 99%

Enzymatic Activity of Xyloglucan Xylosyltransferase 5

et al. 2016

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“…At least three interacting glycosyltransferases (GTs) of this complex have been identified, i.e., one GT47 member (IRX10/10L) and two GT43 members (IRX9/9L and IRX14/14L) (Jensen et al, 2014;Urbanowicz et al, 2014;Mortimer et al, 2015;Zeng et al, 2016). In Populus, IRX9/9L function is performed by PtGT43A, B, or E and IRX14/14L function by PtGT43C or D (Lee et al, 2011;Ratke et al, 2015).…”

Section: Primary Cell Wall Polysaccharide Biosynthetic Genes Continuementioning

confidence: 99%

AspWood: High-Spatial-Resolution Transcriptome Profiles Reveal Uncharacterized Modularity of Wood Formation in Populus tremula

et al. 2017

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Trees represent the largest terrestrial carbon sink and a renewable source of ligno-cellulose. There is significant scope for yield and quality improvement in these largely undomesticated species, and efforts to engineer elite varieties will benefit from improved understanding of the transcriptional network underlying cambial growth and wood formation. We generated highspatial-resolution RNA sequencing data spanning the secondary phloem, vascular cambium, and wood-forming tissues of Populus tremula. The transcriptome comprised 28,294 expressed, annotated genes, 78 novel protein-coding genes, and 567 putative long intergenic noncoding RNAs. Most paralogs originating from the Salicaceae whole-genome duplication had diverged expression, with the exception of those highly expressed during secondary cell wall deposition. Coexpression network analyses revealed that regulation of the transcriptome underlying cambial growth and wood formation comprises numerous modules forming a continuum of active processes across the tissues. A comparative analysis revealed that a majority of these modules are conserved in Picea abies. The high spatial resolution of our data enabled identification of novel roles for characterized genes involved in xylan and cellulose biosynthesis, regulators of xylem vessel and fiber differentiation and lignification. An associated web resource (AspWood, http://aspwood.popgenie.org) provides interactive tools for exploring the expression profiles and coexpression network.

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“…These three sets of genes play distinct roles in xylan synthesis, and double mutants lacking any of the pairs have either little to no xylan compared with the wild type (Brown et al, 2009;Lee et al, 2010;Wu et al, 2010). So far, only IRX10 and IRX10-L proteins were unambiguously demonstrated to function as xylan synthases in vitro (Jensen et al, 2014;Urbanowicz et al, 2014). Although IRX9 and IRX14 expression promotes xylan XylT activity in Arabidopsis and tobacco (Nicotiana tabacum) microsomes (Lee et al, 2010(Lee et al, , 2012bWu et al, 2010), their biochemical functions are unclear.…”

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confidence: 99%

Highly Branched Xylan Made by IRX14 and MUCI21 Links Mucilage to Arabidopsis Seeds

et al. 2015

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ORCID IDs: 0000-0001-9105-014X (C.V.); 0000-0003-4576-6774 (M.H.-W.S.).All cells of terrestrial plants are fortified by walls composed of crystalline cellulose microfibrils and a variety of matrix polymers. Xylans are the second most abundant type of polysaccharides on Earth. Previous studies of Arabidopsis (Arabidopsis thaliana) irregular xylem (irx) mutants, with collapsed xylem vessels and dwarfed stature, highlighted the importance of this cell wall component and revealed multiple players required for its synthesis. Nevertheless, xylan elongation and substitution are complex processes that remain poorly understood. Recently, seed coat epidermal cells were shown to provide an excellent system for deciphering hemicellulose production. Using a coexpression and sequence-based strategy, we predicted several MUCILAGE-RELATED (MUCI) genes that encode glycosyltransferases (GTs) involved in the production of xylan. We now show that MUCI21, a member of an uncharacterized clade of the GT61 family, and IRX14 (GT43 protein) are essential for the synthesis of highly branched xylan in seed coat epidermal cells. Our results reveal that xylan is the most abundant xylose-rich component in Arabidopsis seed mucilage and is required to maintain its architecture. Characterization of muci21 and irx14 single and double mutants indicates that MUCI21 is a Golgi-localized protein that likely facilitates the addition of xylose residues directly to the xylan backbone. These unique branches seem to be necessary for pectin attachment to the seed surface, while the xylan backbone maintains cellulose distribution. Evaluation of muci21 and irx14 alongside mutants that disrupt other wall components suggests that mucilage adherence is maintained by complex interactions between several polymers: cellulose, xylans, pectins, and glycoproteins.

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Arabidopsis thaliana IRX10 and two related proteins from psyllium and Physcomitrella patens are xylan xylosyltransferases

Cited by 90 publications

References 53 publications

Enzymatic Activity of Xyloglucan Xylosyltransferase 5

Enzymatic Activity of Xyloglucan Xylosyltransferase 5

AspWood: High-Spatial-Resolution Transcriptome Profiles Reveal Uncharacterized Modularity of Wood Formation in Populus tremula

Highly Branched Xylan Made by IRX14 and MUCI21 Links Mucilage to Arabidopsis Seeds

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