Alpha1,3-L-fucosyltransferase expression in developing human myeloid cells. Antigenic, enzymatic, and mRNA analyses.
In an attempt to correlate the cell surface expression of Lex and sialyl-Lex structures in immature and mature myeloid cells with the genes expressing alpha1,3-fucosyltransferase(s) we have examined: 1) the properties of the cellular alpha1,3-fucosyltransferases and the mRNA transcripts corresponding to the five cloned genes, Fuc-TIII, Fuc-TIV, Fuc-TV, Fuc-TVI, and Fuc-TVII, in mature granulocytes and in the myeloid cell line HL-60, before and after dimethyl sulfoxide-induced differentiation and 2) the properties of the alpha1,3-fucosyltransferases expressed in COS-7 cells transfected with plasmids containing Fuc-TIV and Fuc-TVII cDNAs. The previously shown increase in cell surface expression of sialyl-Lex on differentiation of HL-60 cells (Skacel P. O., Edwards A. J., Harrison C. T., and Watkins W. M. (1991) Blood 78, 1452-1460) is accompanied by a sharp fall in expression of Fuc-TIV mRNA and a persistence of expression of Fuc-TVII mRNA. The properties of the alpha1,3-fucosyltransferase expressed in COS-7 cells transfected with Fuc-TIV are consistent with this being the major gene responsible for the expression of Lex in the immature myeloid cells. In Northern blot analyses, no transcripts of Fuc-TIII, Fuc-TV, or Fuc-TVI were detected in total RNA from mature granulocytes or mRNA from HL-60 cells before or after differentiation. In total RNA from mature granulocytes, Fuc-TIV transcripts were only faintly visible, whereas Fuc-TVII transcripts were quite definitely expressed. The specificity properties of Fuc-TVII expressed in COS-7 cells are consistent with this gene being the major candidate alpha1, 3-fucosyltransferase controlling the expression of sialyl-Lex on mature cells. However, Lex continues to be expressed on the surface of mature granulocytes and cell extracts retain the capacity to transfer fucose to non-sialylated acceptor substrates. The question therefore remains as to whether these properties result from the weakly expressed Fuc-TIV gene or whether another alpha1, 3-fucosyltransferase gene remains to be identified.
Clarke
J L
JL
Department of Haematology, Royal Postgraduate Medical School, Hammersmith Hospital, London, W12 ONN, United Kingdom.
Watkins
W
W
D000818:Animals; D001854:Bone Marrow Cells; D002454:Cell Differentiation; D002522:Chlorocebus aethiops; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D005647:Fucosyltransferases / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D006098:Granulocytes / Q000201:enzymology; D006358:Hot Temperature; D006801:Humans; D011489:Protein Denaturation; D012333:RNA, Messenger / Q000235:genetics; D013379:Substrate Specificity; D013439:Sulfhydryl Reagents / Q000494:pharmacology; D014162:Transfection
D012333:RNA, Messenger; D013439:Sulfhydryl Reagents; D005647:Fucosyltransferases; C031692:galactoside 3-fucosyltransferase; D004121:Dimethyl Sulfoxide