title: Functional analysis of complexes with mixed primary and secondary cellulose synthases.
abstract: In higher plants, cellulose is synthesized by cellulose synthase complexes, which contain multiple isoforms of cellulose synthases (CESAs). Among the total 10 CESA genes in Arabidopsis, recessive mutations at three of them cause the collapse of mature xylem cells in inflorescence stems of Arabidopsis (irx1(cesa8), irx3(cesa7) and irx5(cesa4)). These CESA genes are considered secondary cell wall CESAs. The others (the function CESA10 is still unknown) are thought to be specialized for cellulose synthesis in the primary cell wall. A split-ubiquitin membrane yeast two-hybrid system was used to assess interactions among four primary CESAs (CESA1, CESA2, CESA3, CESA6) and three secondary CESAs (CESA4, CESA7, CESA8). Our results showed that primary CESAs could physically interact with secondary CESAs in a limited fashion. Analysis of transgenic lines showed that CESA1 could partially rescue irx1(cesa8) null mutants, resulting in complementation of the plant growth defect, collapsed xylem and cellulose content deficiency. These results suggest that mixed primary and secondary CESA complexes are functional using experimental set-ups.
authors.affiliation: Department of Biochemistry and Molecular Biology; The Center for LignoCellulose Structure and Formation; Pennsylvania State University; University Park, PA USA.
authors.forename: Shundai
authors.initials: S
authors.lastname: Li
authors.forename: Lei
authors.initials: L
authors.lastname: Lei
authors.forename: Ying
authors.initials: Y
authors.lastname: Gu
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002473:Cell Wall / Q000201:enzymology*; D002482:Cellulose / Q000235:genetics / Q000378:metabolism*; D017343:Genes, Plant; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism*; D056626:Inflorescence / Q000201:enzymology; D009154:Mutation; D018547:Plant Stems / Q000201:enzymology; D018514:Plant Structures / Q000201:enzymology*; D030821:Plants, Genetically Modified; D020033:Protein Isoforms; D020798:Two-Hybrid System Techniques; D052584:Xylem / Q000201:enzymology
chemical_list: D029681:Arabidopsis Proteins; D020033:Protein Isoforms; D002482:Cellulose; C110227:CESA1 protein, Arabidopsis; C420969:CESA8 protein, Arabidopsis; D005964:Glucosyltransferases; C478648:cellulose synthase
keywords: cellulose; cellulose synthase complex (CSC); primary cell wall; promoter swap; secondary cell wall