title: A CMP-sialic acid transporter cloned from Arabidopsis thaliana.
abstract: Sialylation of glycans is ubiquitous in vertebrates, but was believed to be absent in plants, arthropods, and fungi. However, recently evidence has been provided for the presence of sialic acid in these evolutionary clades. In addition, homologs of mammalian genes involved in sialylation can be found in the genomes of these taxa and for some Drosophila enzymes, involvement in sialic acid metabolism has been documented. In plant genomes, homologs of sialyltransferase genes have been identified, but there activity could not be confirmed. Several mammalian cell lines exist with defects in the sialylation pathway. One of these is the Chinese hamster ovary cell line Lec2, deficient in CMP-sialic acid transport to the Golgi lumen. These mutants provide the possibility to clone genes by functional complementation. Using expression cloning, we have identified an Arabidopsis thaliana nucleotide sugar transporter that is able to complement the CMP-sialic acid transport deficiency of Lec2 cells. The isolated gene (At5g41760) is a member of the triose-phosphate/nucleotide sugar transporter gene family. Recombinant expression of the gene in yeast and testing in vitro confirmed its ability to transport CMP-sialic acid.
authors.affiliation: Zelluläre Chemie, Zentrum Biochemie, Medizinische Hochschule Hannover, Carl-Neuberg-Strasse 1, D-30625 Hannover, Germany. Bakker.Hans@mh-hannover.de
authors.forename: Hans
authors.initials: H
authors.lastname: Bakker
authors.forename: Françoise
authors.initials: F
authors.lastname: Routier
authors.forename: Angel
authors.initials: A
authors.lastname: Ashikov
authors.forename: Detlef
authors.initials: D
authors.lastname: Neumann
authors.forename: Dirk
authors.initials: D
authors.lastname: Bosch
authors.forename: Rita
authors.initials: R
authors.lastname: Gerardy-Schahn
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000737:chemistry*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000302:isolation & purification*; D016466:CHO Cells; D003001:Cloning, Molecular; D006224:Cricetinae; D003412:Cricetulus; D003569:Cytidine Monophosphate N-Acetylneuraminic Acid / Q000378:metabolism*; D005434:Flow Cytometry; D026901:Membrane Transport Proteins / Q000302:isolation & purification*; D033704:Nucleotide Transport Proteins / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D029681:Arabidopsis Proteins; C532043:At5g41760 protein, Arabidopsis; D026901:Membrane Transport Proteins; D033704:Nucleotide Transport Proteins; D003569:Cytidine Monophosphate N-Acetylneuraminic Acid