Independent regulation of Fuc-TIV and Fuc-TVII genes leading to modulation of cell surface antigen expression in developing myeloid cells.
Fucosylated antigen expression, fucosyltransferase activities and expression of Fuc-TIV and Fuc-TVII genes have been measured in the human leukemic cell lines KG1a, arrested at the undifferentiated myeloblast stage of maturation and KG1, arrested at the myeloblast and early promyelocytic stage. The results are compared with those we earlier found for the later promyelocytic cell line HL-60 and the myelocyte form into which HL-60 cells can be induced to differentiate. These leukemic cell lines, and the differentiated HL-60 cells, are believed to correspond to four successive stages of myeloid maturation in the bone marrow. Fuc-TVII mRNA was strongly expressed in the myeloblastic KG1a cells but expression was less in KG1 and HL-60 cells. In contrast to the sharp fall in Fuc-TIV expression observed on differentiation of HL-60 cells, the expression of Fuc-TIV mRNA showed a progressive increase from KG1a to HL-60 cells; thus the peak of expression of this gene was at the HL-60 promyelocyte stage. This peak correlated with an increase in fucosyltransferase activity with nonsialylated acceptors and the transitory downregulation of cell surface sialyl-Le(x) expression and upregulation of Le(x), VIM-2 and Le(y) expression. The variations in levels of expression of the fucosylated antigens on the surface of the developing myeloid cells therefore correlate with variations in mRNA expression arising from the independent regulation of Fuc-TIV and Fuc-TVII genes.
Clarke
J L
JL
Department of Haematology, Royal Postgraduate Medical School, Hammersmith Hospital, London, UK.
Watkins
W M
WM
D000818:Animals; D000954:Antigens, Surface / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification; D001854:Bone Marrow Cells / Q000166:cytology / Q000276:immunology*; D019556:COS Cells; D002454:Cell Differentiation; D005033:Ethylmaleimide / Q000494:pharmacology; D005434:Flow Cytometry; D005647:Fucosyltransferases / Q000235:genetics*; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007527:Isoenzymes / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D013379:Substrate Specificity; D014407:Tumor Cells, Cultured
D000954:Antigens, Surface; D007527:Isoenzymes; D012333:RNA, Messenger; D005647:Fucosyltransferases; D005033:Ethylmaleimide