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ß-Glycosyltransferase Family Tree

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News from the world of cellulose:

  Cellulose is Critical for Biofilm Formation in Salmonella
C. Solano, B. García, J. Valle, C. Berasain, J.-M. Ghigo, C. Gamazo and I. Lasa, 
"Genetic analysis of Salmonella enteritidis biofilm formation: critical role of cellulose"
Molecular Microbiology (Volume 43, Issue 3, February 2002)

  Cloning and Sequencing of the Beta-glucosidase Gene from Acetobacter xylinum ATCC 23769
reported by Kenji TAJIMA, Katsutoshi NAKAJIMA, Hitomi YAMASHITA, Toshikazu SHIBA, Masanobu MUNEKATA, and Mitsuo TAKAI in DNA Research 8 (2001), pages 263-269

ABSTRACT: The beta-glucosidase gene (bglxA) was cloned from the genomic DNA of Acetobacter xylinum ATCC 23769 and its nucleotide sequence (2200 bp) was determined. This bglxA gene was present downstream of the cellulose synthase operon and coded for a polypeptide of molecular mass 79 kDa. The overexpression of the beta-glucosidase in A. xylinum caused a tenfold increase in activity compared to the wild-type strain. In addition, the action pattern of the enzyme was identified as G3ase activity. The deduced amino acid sequence of the bglxA gene showed 72.3%, 49.6%, and 45.1% identity with the beta-glucosidases from A. xylinum subsp. sucrofermentans, Cellvibrio gilvus, and Mycobacterium tuberculosis, respectively. Based on amino acid sequence similarities, the beta-glucosidase (BglxA) was assigned to family 3 of the glycosyl hydrolases.   
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 "Resistance against Herbicide Isoxaben and Cellulose Deficiency Caused by Distinct Mutations in Same Cellulose Synthase Isoform CESA61"
Thierry Desprez, Samantha Vernhettes, Mathilde Fagard, Guislaine Refrégier, Thierry Desnos, Estelle Aletti, Nicolas Py, Sandra Pelletier, and Herman Höfte
(Plant Physiology, February 2002, Vol. 128, pp. 482-490)

ABSTRACT: Isoxaben is a pre-emergence herbicide that inhibits cellulose biosynthesis in higher plants. Two loci identified by isoxaben-resistant mutants (ixr1-1, ixr1-2, and ixr2-1) in Arabidopsis have been reported previously. IXR1 was recently shown to encode the cellulose synthase catalytic subunit CESA3 (W.-R. Scheible, R. Eshed, T. Richmond, D. Delmer, and C. Somerville [2001] Proc Natl Acad Sci USA 98: 10079-10084). Here, we report on the cloning of IXR2, and show that it encodes another cellulose synthase isoform, CESA6. ixr2-1 carries a mutation substituting an amino acid close to the C terminus of CESA6 that is highly conserved among CESA family members. Transformation of wild-type plants with the mutated gene and not with the wild-type gene conferred increased resistance against the herbicide. The simplest interpretation for the existence of these two isoxaben-resistant loci is that CESA3 and CESA6 have redundant functions. However, loss of function procuste1 alleles of CESA6 were previously shown to have a strong growth defect and reduced cellulose content in roots and dark-grown hypocotyls. This indicates that in these mutants, the presence of CESA3 does not compensate for the absence of CESA6 in roots and dark-grown hypocotyls, which argues against redundant functions for CESA3 and CESA6. Together, these observations are compatible with a model in which CESA6 and CESA3 are active as a protein complex.

 
 "Cellulose Synthase-like Genes in Rice"
Samuel P. Hazen, John S. Scott-Craig, and Jonathan D. Walton
(Plant Physiology, February 2002, Vol. 128, pp. 336-340)

 Ninth International Cell Wall Meeting
Peter V. Minorsky reports (Plant Physiology, February 2002, Vol. 128, pp. 345-353) on the Ninth International Cell Wall Meeting held in September 2001, in Toulouse, France

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