The expression of prion protein (PrP(C)) in the megakaryocyte lineage.
BACKGROUND
Cellular prion protein (PrP(C)) is a naturally occurring protein in normal individuals which adopts an abnormal conformation, termed scrapie prion protein (PrP(Sc)) that is associated with disease. There is great concern that clinically asymptomatic variant Creutzfeldt-Jacob disease (vCJD) may transmit PrP(Sc) in blood transfusion products. PrP(C) is widely expressed and has been found in human blood. The majority of cellular borne PrP(C) is associated with platelets (84%). Although PrP(C) mRNA has been demonstrated in platelets, the quantity is unknown and may not reflect the total PrP(C) present.


OBJECTIVE
To investigate the expression of PrP(C) in the megakaryocyte lineage.


METHODS
The expression of PrP(C) was studied in CD34+ cells, cultured megakaryocytes and platelets using electron microscopy, flow cytometry, semi-quantitative RT-PCR and immunofluorescence confocal microscopy.


CONCLUSIONS
The expression of PrP(C) appeared to increase with differentiation and polyploidization in the megakaryocyte lineage. PrP(C) was located within platelet alpha-granules and its source is likely to be from megakaryocyte precursors. If PrP(Sc) has a similar distribution, these results have implications for the selection of blood donors and preparation of cell-depleted blood products.
Starke
R
R
Department of Haematology, University College London, London, UK. r.starke@ucl.ac.uk
Harrison
P
P
Mackie
I
I
Wang
G
G
Erusalimsky
J D
JD
Gale
R
R
Massé
J-M
JM
Cramer
E
E
Pizzey
A
A
Biggerstaff
J
J
Machin
S
S
D018952:Antigens, CD34; D001792:Blood Platelets / Q000737:chemistry; D002454:Cell Differentiation; D019070:Cell Lineage; D002478:Cells, Cultured; D003594:Cytoplasmic Granules / Q000737:chemistry; D006412:Hematopoietic Stem Cells / Q000737:chemistry; D006801:Humans; D008533:Megakaryocytes / Q000737:chemistry* / Q000166:cytology; D018621:PrPC Proteins / Q000032:analysis* / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis
D018952:Antigens, CD34; D018621:PrPC Proteins; D012333:RNA, Messenger