Document Detail


Arabidopsis cyt1 mutants are deficient in a mannose-1-phosphate guanylyltransferase and point to a requirement of N-linked glycosylation for cellulose biosynthesis.
MedLine Citation:
PMID:  11226227     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Arabidopsis cyt1 mutants have a complex phenotype indicative of a severe defect in cell wall biogenesis. Mutant embryos arrest as wide, heart-shaped structures characterized by ectopic accumulation of callose and the occurrence of incomplete cell walls. Texture and thickness of the cell walls are irregular, and unesterified pectins show an abnormally diffuse distribution. To determine the molecular basis of these defects, we have cloned the CYT1 gene by a map-based approach and found that it encodes mannose-1-phosphate guanylyltransferase. A weak mutation in the same gene, called vtc1, has previously been identified on the basis of ozone sensitivity due to reduced levels of ascorbic acid. Mutant cyt1 embryos are deficient in N-glycosylation and have an altered composition of cell wall polysaccharides. Most notably, they show a 5-fold decrease in cellulose content. Characteristic aspects of the cyt1 phenotype, including radial swelling and accumulation of callose, can be mimicked with the inhibitor of N-glycosylation, tunicamycin. Our results suggest that N-glycosylation is required for cellulose biosynthesis and that a deficiency in this process can account for most phenotypic features of cyt1 embryos.
Authors:
W Lukowitz; T C Nickle; D W Meinke; R L Last; P L Conklin; C R Somerville
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2001-02-20
Journal Detail:
Title:  Proceedings of the National Academy of Sciences of the United States of America     Volume:  98     ISSN:  0027-8424     ISO Abbreviation:  Proc. Natl. Acad. Sci. U.S.A.     Publication Date:  2001 Feb 
Date Detail:
Created Date:  2001-03-06     Completed Date:  2001-09-13     Revised Date:  2010-09-14    
Medline Journal Info:
Nlm Unique ID:  7505876     Medline TA:  Proc Natl Acad Sci U S A     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2262-7     Citation Subset:  IM    
Affiliation:
Carnegie Institution of Washington, Department of Plant Biology, Stanford, CA 94305, USA. lubo@andrew2.stanford.edu
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MeSH Terms
Descriptor/Qualifier:
Amino Acid Sequence
Arabidopsis / enzymology,  genetics*,  metabolism
Blotting, Northern
Blotting, Western
Cellulose / biosynthesis*
Cloning, Molecular
Genes, Plant*
Glycosylation
Molecular Sequence Data
Mutation*
Nucleotidyltransferases / genetics*,  metabolism
Plant Roots / metabolism
Sequence Homology, Amino Acid
Chemical
Reg. No./Substance:
9004-34-6/Cellulose; EC 2.7.7.-/Nucleotidyltransferases; EC 2.7.7.22/mannose-1-phosphate guanylyltransferase (GDP)
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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