Molecular cloning of a fourth member of a human alpha (1,3)fucosyltransferase gene family. Multiple homologous sequences that determine expression of the Lewis x, sialyl Lewis x, and difucosyl sialyl Lewis x epitopes.
We and others have previously described the isolation of three human alpha (1,3)fucosyltransferase genes which form the basis of a nascent glycosyltransferase gene family. We now report the molecular cloning and expression of a fourth homologous human alpha (1,3)fucosyltransferase gene. When transfected into mammalian cells, this fucosyltransferase gene is capable of directing expression of the Lewis x (Gal beta 1-->4[Fuc alpha 1-->3]GlcNAc), sialyl Lewis x (NeuNAc alpha 2-->3Gal beta 1-->4 [Fuc alpha 1-->3]GlcNAc), and difucosyl sialyl Lewis x (NeuNAc alpha 2-->3Gal beta 1-->4[Fuc alpha 1-->3]GlcNAc beta 1-->3 Gal beta 1-->4[Fuc alpha 1-->3]GlcNAc) epitopes. The enzyme shares 85% amino acid sequence identity with Fuc-TIII and 89% identity with Fuc-TV but differs substantially in its acceptor substrate requirements. Polymerase chain reaction analyses demonstrate that the gene is syntenic to Fuc-TIII and Fuc-TV on chromosome 19. Southern blot analyses of human genomic DNA demonstrate that these four alpha (1,3)fucosyltransferase genes account for all DNA sequences that cross-hybridize at low stringency with the Fuc-TIII catalytic domain. Using similar methods, a catalytic domain probe from Fuc-TIV identifies a new class of DNA fragments which do not cross-hybridize with the chromosome 19 fucosyltransferase probes. These results extend the molecular definition of a family of human alpha (1,3)fucosyltransferase genes and provide tools for examining fucosyltransferase gene expression.
Weston
B W
BW
Department of Pediatrics, University of Michigan Medical School, Ann Arbor 48109-0650.
Smith
P L
PL
Kelly
R J
RJ
Lowe
J B
JB
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D016466:CHO Cells; D002240:Carbohydrate Sequence; D002460:Cell Line; D002874:Chromosome Mapping; D002888:Chromosomes, Human, Pair 19; D003001:Cloning, Molecular / Q000379:methods; D006224:Cricetinae; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D005434:Flow Cytometry; D005647:Fucosyltransferases / Q000235:genetics* / Q000378:metabolism*; D005796:Genes; D006801:Humans; D006822:Hybrid Cells; D007527:Isoenzymes / Q000235:genetics* / Q000378:metabolism*; D007700:Kinetics; D007983:Lewis Blood Group Antigens; D008969:Molecular Sequence Data; D005810:Multigene Family; D009838:Oligodeoxyribonucleotides; D016133:Polymerase Chain Reaction / Q000379:methods; D015183:Restriction Mapping; D014162:Transfection
D007527:Isoenzymes; D007983:Lewis Blood Group Antigens; D009838:Oligodeoxyribonucleotides; D004247:DNA; D005647:Fucosyltransferases; C031692:galactoside 3-fucosyltransferase