Mechanisms by which the surface expression of the glycosyl-phosphatidylinositol-anchored complement regulatory proteins decay-accelerating factor (CD55) and CD59 is lost in human leukaemia cell lines.

Abstract

We have investigated the mechanisms of defects in the glycosyl-phosphatidylinositol (GPI)-anchored complement regulatory proteins delay-accelerating factor (DAF) and/or CD59 in a panel of human leukaemia cell lines that lack surface expression of these proteins: U937 (DAF+/CD59-), CEM (DAF-/CD59+), TALL (DAF-/CD59-) and a substrain of Ramos [Ramos(-)] (DAF-/CD59-). Northern blotting and reverse transcription-PCR revealed that the main cause of the DAF and/or CD59 deficiency is the failure of mRNA expression in most of the cell lines, except in Ramos(-) in which sufficient mRNA for DAF and CD59 was produced. U937, CEM and TALL cells were not defective in GPI anchor formation as assessed by the detection of other GPI-anchored proteins. No gene abnormality corresponding to DAF or CD59 was detected by Southern blotting. Thus the cause of the defects of DAF and/or CD59 in these leukaemia cell lines except for Ramos(-) is virtually undetectable steady-state levels of the relevant mRNA, most likely attributable to lack of transcription in these cell lines. On the other hand, Ramos(-) cells failed to generate a GPI anchor, whereas they normally expressed DAF and CD59 transcripts. The transfection of phosphatidylinositol-glycan class A (PIG-A) cDNA into Ramos(-) cells restored DAF and CD59 expression, indicating that the defective mechanism in GPI anchor formation is similar to that in paroxysmal noctural haemoglobinuria (PNH) cells, i.e. a deficiency of the PIG-A gene product. Thus the mechanisms of the defects of DAF and/or CD59 in human leukaemia cell lines are not uniform, and in most cases are different from that proposed to cause PNH.

• Authors: M Hatanaka, T Seya, M Matsumoto, T Hara, M Nonaka, N Inoue, J Takeda, A Shimizu
• Journal: The Biochemical journal (Biochem J) Vol. 314 ( Pt 3) Pg. 969-76 (Mar 15 1996) ISSN: 0264-6021 [Print] England
• PMID: 8615796 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antigens, CD
• CD55 Antigens
• CD59 Antigens
• DNA Primers
• Glycosylphosphatidylinositols
• Membrane Proteins
• RNA, Messenger
• Recombinant Proteins
• Thy-1 Antigens
• phosphatidylinositol glycan-class A protein
• Phosphoric Diester Hydrolases
• Type C Phospholipases
• Phosphatidylinositol Diacylglycerol-Lyase

Topics

• Antigens, CD (biosynthesis, genetics)
• Base Sequence
• Blotting, Northern
• Blotting, Southern
• CD55 Antigens (biosynthesis, genetics)
• CD59 Antigens (biosynthesis, genetics)
• Cell Line
• Cell Membrane (physiology)
• DNA Primers
• Gene Expression
• Glycosylphosphatidylinositols (metabolism)
• Hemoglobinuria, Paroxysmal (genetics)
• Humans
• Leukemia
• Membrane Proteins (biosynthesis)
• Molecular Sequence Data
• Phosphatidylinositol Diacylglycerol-Lyase
• Phosphoric Diester Hydrolases (pharmacology)
• Polymerase Chain Reaction
• RNA, Messenger (biosynthesis)
• Recombinant Proteins (biosynthesis)
• Thy-1 Antigens (biosynthesis)
• Transcription, Genetic
• Transfection
• Tumor Cells, Cultured
• Type C Phospholipases