Molecular cloning and characterization of CFT1, a developmentally regulated avian alpha(1,3)-fucosyltransferase gene.
Although coordinate expression of carbohydrate epitopes during development is well described, mechanisms which regulate this expression remain largely unknown. In this study we demonstrate that developing chicken B cells express the LewisX terminal oligosaccharide structure in a stage-specific manner. To examine regulation of this expression, we have cloned and expressed the chicken alpha(1,3)-fucosyltransferase gene involved in LewisX biosynthesis, naming it chicken fucosyltransferase 1 (CFT1). CFT1 is characterized by a single long open reading frame of 356 amino acids encoding a type II transmembrane glycoprotein. The domain structure and predicted amino acid sequence are highly conserved between CFT1 and mammalian FucTIV genes (52.8% and 46.3% identity to mouse and human respectively). In vitro CFT1 fucosyltransferase activity utilizes LacNAc > 3'sialyl-LacNAc acceptors with almost no utilization of other neutral type II (lactose, 2-fucosyllactose), or type I (lacto-N-biose I) acceptors. CFT1-transfected cells make cell surface LewisX (COS-7) and LewisX + VIM-2 structures (Chinese hamster ovary). CFT1 gene expression is tissue-specific and includes embryonic thymus and bursa. Furthermore, expression of the CFT1 gene and cell surface LewisX structures are closely linked during B cell development. These findings reveal the evolutionary conservation between nonmammalian and mammalian alpha(1,3)-fucosyltransferase genes and demonstrate a role for fucosyltransferase gene regulation in the developmental expression of oligosaccharide structures.
Lee
K P
KP
Immune Cell Biology Program, Naval Medical Research Institute, Bethesda, Maryland 20889, USA. rin0kxl@bumed30.med.navy.mil
Carlson
L M
LM
Woodcock
J B
JB
Ramachandra
N
N
Schultz
T L
TL
Davis
T A
TA
Lowe
J B
JB
Thompson
C B
CB
Larsen
R D
RD
D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000201:enzymology*; D001483:Base Sequence; D019556:COS Cells; D002645:Chickens / Q000097:blood* / Q000276:immunology; D003001:Cloning, Molecular; D005647:Fucosyltransferases / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D005796:Genes; D016256:Lewis X Antigen / Q000235:genetics / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D015183:Restriction Mapping; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution
D016256:Lewis X Antigen; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D005647:Fucosyltransferases; C031692:galactoside 3-fucosyltransferase