Cloning of a rat [alpha]1,3-fucosyltransferase gene: a member of the fucosyltransferase IV family

We report the cloning of a rat α1,3-fucosyltransferase gene (rFuc-T), isolated from a rat genomic library by a PCR-cross-hybridization based cloning approach using primers derived from the conserved region of human α1,3-Fuc-T sequences. Comparison of the rFuc-T predicted amino acid sequence with those of previously cloned human and murine fucosyltransferases showed highest degree of homology to murine Fuc-TIV (87% identity) and human Fuc-TIV (78% identity), with lower homology (41-49% identity) to Fuc-TIII, V, VI, and VII. COS-1 cells transfected with the rFuc-T gene expressed a fucosyltransferase activity with type 2 (Galβ1[arrow right]4GlcNAc)-containing oligosaccharides and the glycolipid acceptor neolactotetraosyl-ceramide but only low activity with sialylated substrates; the SSEA-1/Lex antigen was detected in transfected cells by immunocytochemistry. Based on these results, we surmise that rFuc-T is a member of the fucosyltransferase IV family. Northern blot analysis with a rFuc-T specific probe indicated a major transcript of 4.2 kb most abundantly expressed in rat spleen; minor transcripts of different sizes were detected in several tissues, including rat brain. Abbreviations: Fuc-T, fucosyltransferase; SSEA-1, stage specific embryonic antigen or Lewisx (Lex); ELFT, ELAM-1 ligand fucosyltransferase; ELAM, endothelial-leukocyte adhesion molecule; nLc4Cer, neolactotetraosylceramide (Galβ1[arrow right]4GlcNAcβ1[arrow right]3Galβ1[arrow right]4Glcβ1[arrow right]1Cer); NEM, N-ethylmaleimide[PUBLICATION ABSTRACT]