Multiple cellulose synthase catalytic subunits are required for cellulose synthesis in Arabidopsis.
The irregular xylem 1 (irx1) mutant of Arabidopsis has a severe deficiency in the deposition of cellulose in secondary cell walls, which results in collapsed xylem cells. This mutation has been mapped to a 140-kb region of chromosome 4. A cellulose synthase catalytic subunit was found to be located in this region, and genomic clones containing this gene complemented the irx1 mutation. IRX1 shows homology to a previously described cellulose synthase (IRX3). Analysis of the irx1 and irx3 mutant phenotypes demonstrates that both IRX1 and IRX3 are essential for the production of cellulose in the same cell. Thus, IRX1 and IRX3 define distinct classes of catalytic subunits that are both essential for cellulose synthesis in plants. This finding is supported by coprecipitation of IRX1 with IRX3, suggesting that IRX1 and IRX3 are part of the same complex.
Taylor
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NG
School of Biological Sciences, University of Manchester, Manchester, M13 9PT, United Kingdom.
Laurie
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S
Turner
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SR
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins; D001483:Base Sequence; D020134:Catalytic Domain; D002482:Cellulose / Q000096:biosynthesis*; D003001:Cloning, Molecular; D017931:DNA Primers; D018076:DNA, Complementary; D005964:Glucosyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010641:Phenotype; D017386:Sequence Homology, Amino Acid
D029681:Arabidopsis Proteins; D017931:DNA Primers; D018076:DNA, Complementary; D002482:Cellulose; C420969:CESA8 protein, Arabidopsis; D005964:Glucosyltransferases