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First published online May 15, 2003; 10.1104/pp.103.022368 Plant Physiology 132:883-892 (2003) © 2003 American Society of Plant Biologists The GMD1 and GMD2 Genes of Arabidopsis Encode Isoforms of GDP-D-Mannose 4,6-Dehydratase with Cell Type-Specific Expression Patterns1Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269 (C.P.B., G.F.V., W.-D.R.); and Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602 (G.F., M.G.H.)
L-Fucose (L-Fuc) is a monosaccharide constituent of plant cell wall polysaccharides and glycoproteins. The committing step in the de novo synthesis of L-Fuc is catalyzed by GDP-D-mannose 4,6-dehydratase, which, in Arabidopsis, is encoded by the GMD1 and GMD2 (MUR1) genes. To determine the functional significance of this genetic redundancy, the expression patterns of both genes were investigated via promoter-  -glucuronidase fusions and immunolocalization of a Fuc-containing epitope. GMD2 is expressed in most cell types of the root, with the notable exception of the root tip where strong expression of GMD1 is observed. Within shoot organs, GMD1::GUS expression is confined to stipules and pollen grains leading to fucosylation of the walls of these cell types in the mur1 mutant. These results suggest that GMD2 represents the major housekeeping gene for the de novo synthesis of GDP-L-Fuc, whereas GMD1 expression is limited to a number of specialized cell types. We conclude that the synthesis of GDP-L-Fuc is controlled in a cell-autonomous manner by differential expression of two isoforms of the same enzyme.
L-Fuc is a monosaccharide constituent of various glycoproteins and polysaccharides synthesized by plant cells. It is found predominantly in xyloglucan, a hemicellulosic polysaccharide that is believed to cross-link cellulose microfibrils (Bacic et al., 1988  ; Carpita and Gibeaut, 1993). L-Fuc is also present in the pectic polysaccharides rhamnogalacturonan I and II and in root mucilage, which is believed to lubricate the root as it travels through the soil matrix in addition to providing protection during periods of drought (Greenland, 1979; Rougier, 1981; Baldo et al., 1983).
The localization of L-fucosylated xyloglucan polymers within root cell walls has been accomplished with the use of an antibody directed against the terminal L-Fuc epitope of this hemicellulose (Puhlmann et al., 1994
The biosynthesis of L-Fuc occurs through the conversion of GDP-D-Man to GDP-L-Fuc in three catalytic steps: 4,6-dehydration, 3,5-epimerization, and 4-reduction (for review, see Feingold and Avigad, 1980
Cloning of the GMD1 Gene
A cDNA copy of the GMD1 gene was cloned previously (Bonin et al., 1997
Based on our previous findings that the mur1 mutant contains substantial amounts of L-Fuc within its roots, we wished to determine if the GMD1 gene is transcribed within this tissue. Northern blots were performed to determine the transcript size and expression patterns of both GMD1 and GMD2. Total RNA was extracted from roots, leaves, stems, flowers, and siliques. The blot was probed with GMD1 and GMD2. GMD2 transcripts were highly abundant in roots and flowers and less abundant in leaves, stems, and siliques (Fig. 3). GMD1 appeared to be expressed mostly in roots, but after long exposures, weak hybridization was detectable in other tissues, particularly in flowers, even at very high stringency (Fig. 3). The approximate size of each transcript was 1.5 kb for both GMD1 and GMD2, which is in accordance with the longest cDNAs isolated.
To correlate GMD1 mRNA expression with GDP-D-Man 4,6-dehydratase activity in roots, crude protein extracts from mur1 and wild-type roots were assayed for this enzymatic activity. These assays revealed that mur1 root extracts produced less GDP-KDM than extracts from wild-type roots (44% conversion in the case of mur1 versus 57% conversion in the case of wild type). To assay the entire GDP-L-Fuc biosynthetic pathway in wild-type and mur1 roots, NADPH was added to the reaction mixture, permitting the conversion of GDP-KDM to GDP-L-Fuc (Bonin et al., 1997
To verify the predicted function of the GMD1 protein, the open reading frame was cloned into the pET28b expression vector such that a carboxy-terminal His tag was incorporated into the recombinant enzyme, which was utilized for affinity purification of the protein. SDS-PAGE of the recombinant protein before and after purification indicated that GMD1 could be highly purified via nickel-nitrilotriacetic acid agarose (Ni-NTA) chromatography and encodes a protein of approximately 43 kD (Fig. 4), which is in agreement with its predicted size based on the amino acid sequence including the His tag (42.1 kD).
To assay GMD1 for 4,6-dehydratase activity, GDP-D-[14C]Man was incubated with purified recombinant GMD1 protein. As shown in Figure 5, lane 2, GDP-D-[14C]Man was converted to GDP-KDM (seen as a mixture of 6-deoxy-D-talose and D-Rha). These experiments demonstrate that, like the GMD2 protein, GMD1 exhibits GDP-D-Man 4,6-dehydratase activity in vitro.
To further explore the expression patterns of GMD1 and GMD2, DNA sequences upstream of the start codon were transcriptionally fused to GMD1::GUS expression was seen a few days after germination at the tip of the developing primary root (Fig. 6A), whereas GMD2::GUS expression was found in all other regions of the plant except for the root meristem and the proximal part of the elongation zone (Fig. 6B). The expression of GMD1::GUS was primarily localized to the root meristem and columella root cap and showed some irregular expression through the lateral root cap and the epidermal cells close to the root tip at 3 d post-germination, and this expression pattern was maintained throughout growth (Fig. 6A). GMD2::GUS was expressed in a few columella root cap cells and the developing vasculature at 3 d post-germination (Fig. 6B) and also continued to be expressed throughout the growth of the primary root (Fig. 6D). Neither GMD1::GUS nor GMD2::GUS expression was detectable in emerging lateral roots (Fig. 6, C and D, respectively), but expression of both genes occurred at later stages of lateral root development (Fig. 6, E and F, respectively) and mimicked the expression observed within the primary root at maturity (Figs. 6, G and H, respectively). To determine whether GMD1 expression changes in response to the lack of GMD2 activity, we introduced the GMD1::GUS construct into the mur1 genetic background via standard crossing procedures. Staining for GUS activity indicated that the expression pattern of GMD1 was the same in wild-type and mur1 plants (data not shown).
A more extensive analysis of promoter-GUS plants indicated that GMD1 was expressed in some aboveground tissues, specifically in stipules and in pollen grains. GMD1::GUS and GMD2::GUS expression could be seen in leaf stipules at 3 d post-germination (Fig. 6, K and L, respectively). GMD1::GUS expression was not seen at the root-hypocotyl junction or in cotyledons (Fig. 6, I and M, respectively), whereas GMD2::GUS was expressed in both of these regions, specifically within the vasculature and guard cells of the cotyledons (Fig. 6, J and N, inset, respectively). Inspection of true leaves revealed that GMD2::GUS was primarily expressed in trichomes and guard cells (Fig. 6P), whereas GMD1::GUS was not (Fig. 6O). Staining for GUS activity in whole developing florets indicated that GMD1 and GMD2 are transiently expressed in pollen just before anthesis (Fig. 7, A and B). Closer inspection of individual flowers at different stages of development confirmed this initial finding. At early stages of flower development, neither GMD1 nor GMD2 were expressed in pollen grains (Fig. 7, C and E, respectively), but were switched on at a slightly more developed stage (Fig. 7, D and F, respectively). This can be seen more clearly in a close-up of GMD1::GUS and GMD2::GUS anthers (Fig. 7, G and I, respectively). The expression of both GMD2 and GMD1 in only a subset of the pollen may be attributed to a different stage of development for pollen derived from single anthers. After inspecting several flowers, it seemed as if the development of pollen from individual anthers lacked synchronicity. A small percentage of flowers examined had anthers where it appeared as if all of the pollen grains were staining for GUS activity, suggesting that synchronous pollen development may be a rare event. After anthesis, expression of both GMD1 and GMD2 was no longer observed (Fig. 7, H and J). GMD1 transcription was not seen in any other floral organs, whereas GMD2 transcription was observed in portions of the inflorescence stem, the vasculature of flowers, the style, but not the stigma and the ovary (Fig. 7, B, E, and F).
Because aboveground tissues of mur1 plants, which carry a mutation in GMD2, do not contain significant amounts of Fuc as determined by glycosyl composition analyses (Reiter et al., 1993
We have demonstrated that a gene with sequence similarity to the previously characterized GMD2 (MUR1) gene (Fig. 2) encodes a functional GDP-D-Man 4,6-dehydratase that catalyzes the committing step in the conversion of GDP-D-Man to GDP-L-Fuc (Fig. 5). The identification and characterization of a second gene involved in the biosynthesis of L-Fuc adds to our understanding of nucleotide sugar formation in Arabidopsis and raises new questions regarding the regulation of cell wall polysaccharide biosynthesis in plants.
GMD1 transcription appears to be essentially root specific (Fig. 3), although it was also detected in stipules and in pollen grains (Figs. 6 and 7). The expression in roots was expected based on our initial hypothesis that a gene other than GMD2 must be responsible for the presence of L-Fuc in mur1 roots, which is approximately 60% that of wild-type roots (Reiter et al., 1993
We used GMD1::GUS and GMD2::GUS plants to more closely examine the transcriptional expression patterns of these genes in Arabidopsis (Figs. 6 and 7). These experiments have provided us with compelling evidence that GMD1 is not only transcribed within specific cells of the root but is temporally expressed within stipules and pollen. As expected from the presence of L-Fuc in mur1 roots and our GMD1 northern data (Fig. 3), GMD1::GUS expression was found to be localized mainly in the root but appeared to be confined to the tips of both the primary root and lateral roots with particularly strong expression in the meristematic and columellar root cap zones (Fig. 6, A, E, and G). These results are in remarkable agreement with immunolocalization studies carried out with the CCRC-M1 antibody on roots of the mur1 mutant, where only the walls of meristematic and columellar cells of mature roots stained (Freshour et al., 2003
Interestingly, neither GMD1 nor GMD2 appeared to be expressed in the lateral root primordia (Fig. 6, C and D), yet the walls of wild-type root primordia contain fucosylated xyloglucans as demonstrated by CCRC-M1 immunolabeling (Freshour et al., 2003
GMD2 appears to be expressed in all other parts of the plant, which was expected based on our previous characterization of the mur1 mutant and the omnipresence of L-Fuc in Arabidopsis. Aside from the columella root cap, GMD2 expression is switched on within the elongation zone of the root where differentiation of specialized cell types occurs. Specifically, GMD2 is expressed to a high degree in the developing stele (Fig. 6B) and to a lesser degree within surrounding cells. Because specialized transport cells within the vasculature require a strong cell wall to resist conductive forces, the production and insertion of fucosylated polymers may aid in their integrity. Immunolocalization data using the CCRC-M1 antibody did not show significant differences in labeling intensity of the vasculature versus surrounding cells (Freshour et al., 1996
The expression of GMD1 in stipules and pollen was unexpected but could be confirmed by L-Fuc immunolocalization studies in these tissues from mur1 plants. It appears clear that both GMD1 and GMD2 are expressed in pollen to provide Fuc for the synthesis of the pollen grain wall (Fig. 9). In addition, expression of these two genes just before anthesis might provide sufficient amounts of GDP-D-Man 4,6-dehydratase to permit L-Fuc synthesis during pollen tube growth after pollen germination. Labeling of mur1 pollen tubes by the CCRC-M1 antibody has been observed (Freshour et al., 2003
Stipules represented the only vegetative shoot organ where both GMD1 and GMD2 were strongly expressed, presumably reflecting a high demand for GDP-L-Fuc in these leaf-like structures. Stipules from Arabidopsis are characterized by elaborate endomembrane systems (Bowman, 1994 Our examination of the biochemical function and expression patterns of the GMD1 and GMD2 genes raises the question of why Arabidopsis maintains two enzymes with the same catalytic function in a nucleotide sugar interconversion pathway. Although both GMD1 and GMD2 are GDP-D-Man 4,6-dehydratases, the two proteins may differ in terms of protein stability, kinetics, and regulatory properties such as feedback inhibition. Differences in these properties may make one isoform more suitable for specific cell types than the other one. Although L-Fuc can be recycled via a salvage pathway, plants cannot convert this 6-deoxysugar into other monosaccharides, making it an end product destined to be incorporated into cell wall polymers and glycoproteins. Accordingly, the de novo synthesis of GDP-L-Fuc needs to be tightly regulated, presumably in part at the posttranscriptional and/or posttranslational levels.
The final steps in the conversion of GDP-D-Man to GDP-L-Fuc are catalyzed by GDP-L-Fuc synthase, an enzyme encoded by the GER1 gene in Arabidopsis (Bonin and Reiter, 2000
Plant Material Plants were grown in environmental chambers at 23°C and 60% to 70% humidity under continuous fluorescent light (60–70 µ mol m–2 s–1). Wild-type plants of the Columbia ecotype were used for the isolation of DNA and RNA.
GMD1 genomic clones were isolated from a
Nucleic Acid Sequence Determination and Analysis
RNA was isolated from different organs of Arabidopsis plants as described previously (Bonin et al., 1997
The sequences of oligonucleotide primers used for cloning of the GMD1 coding region into the pET28b expression vector (Novagen, Madison, WI) were as follows: GMD1/pET28b-upper, 5'-TCCCATGGCCTCCAGATCTCTCAATGGCG-3'; and GMD1/pET28b-lower, 5'-TAAGCGGCCGCCGGTTGCTGCTGAGCGTCC-3', engineering an NcoI site into the upper primer and an NotI site into the lower primer. The PCR was performed in a volume of 30 µL with approximately 50 ng of template (wild-type Columbia DNA) using a model 2400 GeneAmp thermocycler and PCR Core Reagents (Perkin Elmer, Foster City, CA) with the following conditions: denaturation of the DNA at 95°C for 3 min, followed by 30 cycles of denaturation at 94°C for 30 s, annealing at 60°C for 1 min, extension at 72°C for 1 min, and final extension at 72°C for 7 min. One unit of Taq DNA polymerase and 1 µg of each primer were used in the reaction, and the final concentration of MgCl2 was 2 mM. The GMD1 PCR product was cloned into the pET28b expression vector as follows: A PCR fragment of the expected size was purified from an agarose gel using the Qiaquick gel extraction kit (Qiagen), digested with NcoI and NotI, and purified with the Qiaquick PCR purification kit. The pET28b vector was digested with NcoI and NotI and purified as above. Ligation of vector to insert DNA was followed by transformation of the construct into E. coli BL21 (DE3) competent cells according to the manufacturer's protocol (Stratagene).
Purification of the recombinant protein via Ni-NTA columns was done according to the manufacturer's protocol (Qiagen) with slight modifications of induction conditions. Culture flasks containing 50 mL of Luria-Bertani broth and 50 µg mL–1 of kanamycin were inoculated with 1 mL of an overnight culture and grown to an OD600 of approximately 0.6 at 37°C in a rotary shaker at 250 rpm. Isopropyl
Crude enzyme extracts of Arabidopsis were prepared as described earlier (Bonin et al., 1997
To obtain regulatory sequences upstream of the GMD1 and GMD2 coding regions, bacterial artificial chromosomes (BACs) were screened using gene-specific probes. Texas A&M University and Institut für Genbiologische Forschung BAC filters provided by the Arabidopsis Biological Resource Center were screened with 32P-labeled GMD1 and GMD2 probes, respectively, leading to the identification of four Texas A&M University BACs hybridizing to the GMD1 probe and seven Institut für Genbiologische Forschung BACs hybridizing to the GMD2 probe. Restriction analysis and Southern hybridizations were performed with these BACs to determine the amount of sequence upstream of the start codon. A 2.2-kb PstI/XhoI fragment corresponding to GMD1, which contains 2.1 kb of sequence upstream of the start codon, and a 5.0-kb BglII/ClaI fragment corresponding to GMD2, which contains 3.5 kb of sequence upstream of the start codon, were cloned separately into pBluescript KS+ and transformed into E. coli XL1-Blue MRF1 as described above. To clone part of the 2.2-kb GMD1 fragment into pCAMBIA 1391Z (Center for the Application of Molecular Biology to International Agriculture, Canberra, Australia), PCR was performed using a T7 primer located in the vector and a GMD1-specific primer. The sequence of the oligonucleotide primer used for cloning of the GMD1 upstream region into the pCAMBIA 1391Z vector was as follows: PGDgus, 5'-AAGGATCCATCAGAAGAAATGATTGG-3', incorporating a BamHI site. The last 18 nucleotides of this primer corresponded to positions –28 to –45 relative to the GMD1 translational initiation codon. The PCR product and vector were then cleaved with BamHI and PstI, purified, ligated, and transformed first into E. coli XL1-Blue MRF1, followed by electroporation into Agrobacterium tumefaciens GV3101 using a Bio-Rad Genepulser. One of several kanamycin-resistant colonies was then used to transform Arabidopsis via vacuum infiltration (Bechtold et al., 1993 The regulatory sequences of the GMD2 gene were cloned in a similar fashion except that a GMD2-specific primer and the pCAMBIA 1381Z vector were used. The sequence of the oligonucleotide primer used for cloning of the GMD2 upstream region into the pCAMBIA 1381Z vector was as follows: PMRgus, 5'-AATTGTCGACGGATCTGGGATTTCAGAG-3' incorporating a SalI site. The last 19 nucleotides of this primer corresponded to positions –13 to –31 relative to the GMD2 translational initiation codon. The remaining steps for cloning were the same as for the GMD1 construct described above except that SalI and BamHI were used.
Promoter::GUS plants were stained for GUS activity as described by Jefferson et al. (1987
Immunolocalization of the Fuc-containing CCRC-M1 epitope was carried out as described by Freshour et al. (1996
We would like to thank J. Peter Gogarten for the  EMBL3 genomic library, the Arabidopsis Biological Research Center for providing DNA clones, and the Center for the Application of Molecular Biology to International Agriculture (Canberra, Australia) for plant transformation vectors. Received February 19, 2003; returned for revision March 20, 2003; accepted March 27, 2003.
Article, publication date, and citation information can be found at www.plantphysiol.org/cgi/doi/10.1104/pp.103.022368.
1 This work was supported by the Department of Energy's Energy Biosciences Program (grant nos. DE–FG02–95ER20203 and DE–FG02–96ER20220).
2 Present address: Department of Biochemistry and Molecular Biophysics, Columbia University, Hammer Health Sciences Bldg, Room 1104, 701 West 168th Street, New York, NY 10032.
3 Present address: National Renewable Energy Laboratory, 1617 Cole Blvd, Golden, CO 80401. * Corresponding author; e-mail wdreiter{at}uconnvm.uconn.edu; fax 860–486–4331.
Arabidopsis Genome Initiative (2000) Analysis of the genome sequence of the flowering plant Arabidopsis thaliana. Nature 408: 796–815[CrossRef][Medline] Bacic A, Harris PJ, Stone BA (1988) Structure and function of plant cell walls. In PK Stumpf, EE Conn, eds, The Biochemistry of Plants, Vol 14. Academic Press, New York, pp 297–371 Baldo BA, Reid AL, Boniface PA (1983) Lectins as cytochemical probes of the developing wheat grain: IV. Demonstration of mucilage containing L-fucose associated with roots in ungerminated grain. Aust J Plant Physiol 10: 459–470 Bechtold N, Ellis J, Pelletier G (1993) In planta Agrobacterium mediated gene transfer by infiltration of adult Arabidopsis thaliana plants. C R Acad Sci Paris Life Sci 316: 1194–1199
Bonin CP, Potter I, Vanzin GF, Reiter W-D (1997) The MUR1 gene of Arabidopsis thaliana encodes an isoform of GDP-D-mannose-4,6-dehydratase catalyzing the first step in the de novo synthesis of GDP-L-fucose. Proc Natl Acad Sci USA 94: 2085–2090 Bonin CP, Reiter W-D (2000) A bifunctional epimerase-reductase acts downstream of the MUR1 gene product and completes the de novo synthesis of GDP-L-fucose in Arabidopsis. Plant J 21: 445–454[CrossRef][Web of Science][Medline] Bowman J (1994) Arabidopsis. An Atlas of Morphology and Development. Springer Verlag, New York Carpita NC, Gibeaut DM (1993) Structural models of primary cell walls in flowering plants: consistency of molecular structure with the physical properties of the walls during growth. Plant J 3: 1–30[CrossRef][Web of Science][Medline]
Church GM, Gilbert W (1984) Genomic sequencing. Proc Natl Acad Sci USA 81: 1991–1995 Feingold DS, Avigad G (1980) Sugar nucleotide transformations in plants. In PK Stumpf, EE Conn, eds, The Biochemistry of Plants, Vol 2. Academic Press, New York, pp 101–170
Freshour G, Bonin CP, Reiter W-D, Alberheim P, Darvill AD, Hahn MG (2003) Distribution of fucose-containing xyloglucans in cell walls of the mur1 mutant of Arabidopsis. Plant Physiol 131: 1602–1612 Freshour G, Clay RP, Fuller MS, Albersheim P, Darvill AG, Hahn MG (1996) Developmental and tissue-specific structural alterations of the cell wall polysaccharides of Arabidopsis thaliana roots. Plant Physiol 110: 1413–1429[Abstract] Fry SC (1988) The growing plant cell wall: chemical and metabolic analysis. John Wiley and Sons, New York Greenland DJ (1979) The physics and chemistry of the soil-root interface: some comments. In JL Harley, RS Russel, eds, The Soil-Root Interface. Academic Press, London, pp 83–89 Haughn GW, Somerville C (1986) Sulfonylurea-resistant mutants of Arabidopsis thaliana. Mol Gen Genet 204: 430–434[CrossRef][Web of Science] Jefferson RA, Kavanaugh TA, Bevan MW (1987) GUS fusions: beta-glucuronidase as a sensitive and versatile gene fusion marker in higher plants. EMBO J 13: 3901–3907 Mulichak AM, Bonin CP, Reiter W-D, Garavito RM (2002) Structure of the MUR1 GDP-mannose 4,6-dehydratase from Arabidopsis thaliana: implications for ligand binding and specificity. Biochemistry 41: 15578–15589[CrossRef][Medline] Murashige T, Skoog F (1962) A revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiol Plant 15: 473–497[CrossRef]
Ohyama C, Smith PL, Angata K, Fukuda MN, Lowe JB, Fukuda M (1998) Molecular cloning and expression of GDP-D-mannose-4,6-dehydratase, a key enzyme for fucose metabolism defective in Lec13 cells. J Biol Chem 273: 14582–14587
O'Neill MA, Eberhard S, Albersheim P, Darvill AG (2001) Arabidopsis growth requires borate cross-linking of the cell wall pectic polysaccharide rhamnogalacturonan II. Science 294: 846–849
Puhlmann J, Bucheli E, Swain MJ, Dunning N, Albersheim P, Darvill AG, Hahn MG (1994) Generation of monoclonal antibodies against plant cell wall polysaccharides: I. Characterization of a monoclonal antibody to a terminal (1 Reiter W-D, Chapple CCS, Somerville CR (1993) Altered growth and cell walls in a fucose-deficient mutant of Arabidopsis. Science 261: 1032–1035 Reiter W-D, Chapple CCS, Somerville CR (1997) Mutants of Arabidopsis thaliana with altered cell wall polysaccharide composition. Plant J 12: 335–345[CrossRef][Web of Science][Medline] Reiter W-D, Vanzin GF (2001) Molecular genetics of nucleotide sugar interconversion pathways in plants. Plant Mol Biol 47: 95–113[CrossRef][Web of Science][Medline] Rougier M (1981) Secretory activity of the root cap. In W Tanner, FA Loewus, eds, Encyclopedia of Plant Physiology, New Series, Vol 13B, Plant Carbohydrates II. Springer-Verlag, Berlin, pp 542–574 Sambrook J, Fritsch EF, Maniatas T (1989) Molecular Cloning: A Laboratory Manual, Ed 2. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY Sturla L, Bisso A, Zanardi D, Benatti U, De Flora A, Tonetti M (1997) Expression, purification and characterization of GDP-D-mannose-4,6-dehydratase from Escherichia coli. FEBS Lett 412: 126–130[CrossRef][Web of Science][Medline]
Sullivan FX, Kumar R, Kriz R, Stahl M, Xu G-Y, Rouse J, Chang X-j, Boodhoo A, Potvin B, Cumming DA (1998) Molecular cloning of human GDP-mannose 4,6-dehydratase and reconstitutions of GDP-fucose biosynthesis in vitro. J Biol Chem 273: 8193–8202
Tonetti M, Sturla L, Bisso A, Benatti U, DeFlora A (1996) Synthesis of GDP-L-fucose by the human FX protein. J Biol Chem 271: 27274–27279 This article has been cited by other articles:
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2)-linked fucosyl-containing epitope. Plant Physiol 104: 699–710
