|
|
 Previous Article | Table of Contents | Next Article 
Blood, Vol. 92 No. 4 (August 15), 1998:
pp. 1091-1096
RAPID COMMUNICATION
Familial Essential Thrombocythemia Associated With One-Base
Deletion in the 5 -Untranslated Region of the
Thrombopoietin Gene
By
Takeshi Kondo,
Mihiro Okabe,
Masayoshi Sanada,
Mitsutoshi Kurosawa,
Sachiko Suzuki,
Masanobu Kobayashi,
Masuo Hosokawa, and
Masahiro Asaka
From the Third Department of Internal Medicine and the Laboratory of
Pathology, Cancer Institute, Hokkaido University School of Medicine,
Sapporo, Hokkaido, Japan; and the Department of Hematology, Niigata
City General Hospital, Niigata-shi, Niigata Prefecture, Japan.
 |
ABSTRACT |
Familial essential thrombocythemia (ET) is inherited in an
autosomal-dominant manner. This finding implies that familial ET may
arise as a consequence of a mutation(s) that activates platelet production. In 1994, the thrombopoietin (TPO) gene was
isolated and cloned. The TPO-TPO receptor, encoded for by the
c-mpl gene, are essential regulators of thrombopoiesis.
Alterations of TPO or c-Mpl thus may constitute a pathogenic event
leading to familial ET. In a case of familial ET presented in our
institute, serum TPO levels were significantly elevated in affected
members of the family as compared with nonaffected members. Moreover,
we identified a one-base deletion in the 5 -untranslated region of the
TPO gene in affected but not in nonaffected family members. In
vitro experiments showed that the identified mutation increased TPO
production. Based on our findings, we propose that this region of the
TPO gene may play a crucial role in regulating TPO expression. Our results strongly suggest that the identified mutation leads to
familial ET.
© 1998 by The American Society of Hematology.
| |
INTRODUCTION |
ESSENTIAL thrombocythemia (ET) belongs to
the entity of chronic myeloproliferative disorders. ET patients present
with an increased platelet count in peripheral blood accompanied by
proliferation of megakaryocytes in the bone marrow. ET generally occurs
in both males and females in middle age. So far, no common genetic
alteration(s) causing the disease has been identified. To date, a few
cases of familial occurrence of ET have been reported, which are
generally inherited in an autosomal-dominant fashion.1-3
Thus, familial ET is likely to be a consequence of mutations of a gene
that presumably is a critical regulator of platelet production. A case
of familial ET presented in our institution. The disease occurred in
three successive generations, possibly by autosomal-dominant
inheritance (Fig 1). FT-2, the propositus, occasionally
presented with thrombocythemia. Her family history showed that
thrombocythemia occurred in several members of the family, and the
pedigree suggested that the disease was inherited in an
autosomal-dominant manner. Detailed clinical examination did not detect
any underlying disease suitable to cause secondary thrombocythemia.
Thus, the affected members in this family were diagnosed as ET. During
the clinical courses, none of the affected members developed any
thrombotic/hemorrhagic symptoms.
View larger version (17K):
[in this window]
[in a new window]
| Fig 1.
A pedigree of the studied family, showing typical
autosomal-dominant inheritance of disease penetration. Members of the
family, designated as FT-1 through FT-8, were clinically examined to
certify affected or not. Solid symbols indicate affected members.
Circles denote female family members, squares male family members, and symbols with a slash deceased family members. Plain numerals indicate peripheral platelet count, and italic numerals indicate serum concentration of TPO.
|
|
The thrombopoietin (TPO) gene was isolated in 1994. TPO
is believed to be a main regulator of platelet
production.4-11 Serum concentration of TPO in the affected
family members was higher than in nonaffected members. After polymerase
chain reaction (PCR)-based amplification of the TPO gene,
hetero-duplex formation, and sequence analysis, one-base deletion in
the 5-untranslated region (UTR) of the TPO gene was
discovered. We propose that this mutation can raise the expression
level of TPO, resulting in a familial occurrence of ET.
| |
MATERIALS AND METHODS |
All studies described were performed after obtaining informed consent
of all family members and healthy volunteers.
Serum levels of TPO.
Serum concentration of TPO was measured by a sensitive sandwich
enzyme-linked immunosorbent assay (ELISA) as described by Tahara et
al.12
Nested PCR amplification of the TPO genome.
Genomic DNA samples were extracted from peripheral leukocytes of the
family members, except FT-1, and from one healthy volunteer. The
structure of TPO genome has been reported by four
groups.10,11,13,14 Three of them claim that the TPO
gene consists of six exons and five introns,10,11,13
whereas one group reported seven exons and six introns.14
We refer here to the report by Sohma et al10 in which the
initiation codon is located in exon 2. All exons of the TPO
gene were amplified by nested PCR with specific primers, which were
designed to amplify all exons of the TPO
genome in overlapping 7 fragments (Fig
2A). The PCR reaction was performed in a
reaction mixture containing 10 mmol/L Tris-HCl (pH 8.3), 50 mmol/L KCl,
2 mmol/L MgCl2, 0.01% (wt/vol) gelatin, 250 µmol/L of
dNTPs, 0.2 µmol/L each of 5- and 3-PCR primers, 0.25 U Taq DNA
polymerase (TaKaRa Ex Taq; Takara Shuzo, Shiga, Japan), and genomic DNA
in a volume of 50 µL. The samples were denatured at 94°C for 2 minutes, followed by 30 cycles of the amplification process, which
consisted of 2 minutes of denaturation at 94°C, 1 minute of annealing
at 55°C, and 2 minutes of extension at 72°C. The second PCR was
performed with 1 µL of the first PCR product as the template. After
the second PCR amplification, the reaction mixtures were inactivated by
the addition of 1 µL of 0.5 mol/L EDTA. Segment 2 of the TPO
gene was amplified with a set of the first PCR primers
(5-CAGGCTGGTCAGCATCTCAA, 5-TACCAGTTACGCGGATAAAG) and a set
of the second PCR primers (5-CCAGGCAGTCTCTTCCTAGA, 5-GGGATAATGTTGGGAGTTCT).
View larger version (41K):
[in this window]
[in a new window]
| Fig 2.
(A) A scheme of the genomic structure of TPO.
According to GenBank accession no. D32046.10 Exon 0 (dashed
box) corresponds to exon 1 of Chang et al.14
In this reference, the initiation codon is located in exon 2. The
TPO genome was divided and amplified by nested PCR. Each PCR
segment spans as described below: segment 1, from nucleotide (nt) 1240 to nt 1600; segment 2, from nt 3100 to nt 3696; segment 3, from nt 3626 to nt 4066; segment 4, from nt 5959 to nt 6440; segment 5, from nt 6390 to nt 6778; segment 6 from nt 6682 to nt 7071; and segment 7, from nt
6954 to nt 7545. (B) Hetero-duplex formation by amplified segment 2 PCR
products. Hetero-duplex bands are indicated by an arrow. Lane 1, PCR
products from a healthy volunteer alone as a control; lane 2, mixture
of PCR products from FT-2 and control; and lane 3, PCR products from FT-2 alone. (C) Hetero-duplex analysis of segment 2 of all family members, except for FT-1. All of the ET-affected members display the
hetero-duplex bands (FT-2, 3, 4, and 6). However, none of the healthy
family members showed hetero-duplex formation in segment 2 (FT-5, 7, and 8). (D) Identification of the mutation in the segment 2 of
TPO gene. The upper panel shows the DNA sequence of wild-type
allele, and the lower panel shows the mutant allele.
|
|
Hetero-duplex analysis and identification of a mutation.
The PCR products from FT-2 were mixed with an equal volume of
corresponding PCR products from a normal control. These mixtures and
each PCR product from either FT-2 or the normal control were used for
hetero-duplex analysis. The samples were denatured for 3 minutes at
96°C and then kept at room temperature for 1 hour to allow duplex
formation. The samples were resolved by electrophoresis in Mutation
Detection Enhancement (MDE) gel (Hydrolink; AT Biochem, Malvern, PA)
for 22 hours at 800 V, and bands were visualized by staining with
ethidium bromide. Genomic samples of other family members were examined
accordingly. When a region containing a mutation was detected with in
the amplified PCR products, the respective PCR products were cloned
into pT7-Blue(R) (Novagen, Madison, WI). Clones were used as templates
for PCR and the products were then analyzed by MDE gel electrophoresis
after mixing with equal amounts of corresponding wild-type PCR
fragments. Clones that manifested hetero-duplex formation were
sequenced by dideoxy chain termination using the Taq dye terminator
cycle sequencing kit and the Model 370A DNA sequencer (Applied
Biosystems, Foster City, CA) to determine the mutation.
Construction of plasmids.
Human TPO cDNA was obtained by reverse transcription-PCR
(RT-PCR). A human liver sample previously obtained from a
patient with liver disease by biopsy for diagnostic purpose was
concomitantly used to amplify human TPO cDNA. One microgram of
total RNA was added into a reaction mixture containing 100 pmol random
primer (GIBCO-BRL, Grand Island, NY) in a volume of 10.5 µL. The
mixture was heated at 96°C for 3 minutes, chilled on ice, and
supplemented with 20 U of RNasin, 4 µL of 5× RT buffer, 2 µL of
0.1 mol/L dithiothreitol (DTT), 2 µL of 10 mmol/L each
of dNTPs, and 100 U of Superscript reverse transcriptase (GIBCO-BRL) in
a volume of 20 µL and then incubated at 42°C for 2 hours. The RT
reaction product was then incubated at 90°C for 5 minutes and chilled
on ice, and 40 µL of distilled water was added. The TPO cDNA
was amplified by PCR with a set of primers
(5-CCAAGCTTAGAGGGCTGCCTGCTGTGCA and 5-GATGTCGGCAGTGTCTGAGA). PCR
products were cloned into pT7-Blue(R) named as pT7-hTPO. pT7-hTPO was
partially digested with HindIII and BamHI. The
HindIII-BamHI fragment containing the 5-UTR and entire
coding region of the TPO cDNA was ligated into
HindIII-BamHI backbone fragment from pBluescript II
KS( ) (Stratagene, La Jolla, CA). The HindIII-Xba I
fragment of human TPO cDNA from this vector was ligated into HindIII-Xba I backbone of pActNPM,15 which
was designated as pAct-wTPO. To construct the TPO expression vector
bearing the identified mutation, the Nco I-Eae I
segment of the TPO cDNA was substituted for by the
corresponding cDNA fragment obtained from FT-2, generating pAct-mTPO.
To construct the TPO-luciferase fusion genes, either wild-type or
mutant partial TPO cDNA was amplified by PCR with a set of
primers (5-CCAAGCTTAGAGGGCTGCCTGCTGTGCA and 5-GAATCATGACCACGAGGA).
These primers contained either the HindIII or BspHI
site, respectively. The HindIII-BspHI fragments of the
amplified cDNAs were ligated into the HindIII-Nco I
backbone of PGV-C2 (Nippon Gene, Toyama, Japan). In these vectors,
expression of the TPO-luciferase fusion gene was driven by the SV40
late promoter. The vector bearing wild-type partial TPO cDNA
was named pWTP-luc, and the vector bearing the mutation was named
pMTP-luc, respectively.
DNA transfection.
L929 cells (5 × 105 cells per 6 cm dish), a
mouse-derived fibroblast cell line, were transfected with 10 µg of
pActC, pAct-wTPO, or pAct-mTPO, respectively, by calcium-phosphate
method, as described before.15 pActC is a control plasmid
devoid of the cDNA insert. After 16 hours of incubation in 3 mL of
Dulbecco's modified Eagle's medium (DMEM) supplemented
with 10% fetal bovine serum, the media were exchanged to 3 mL of DMEM
supplemented with 1% fetal bovine serum. After 72 hours, both cells
and conditioned media were collected. RNA blotting analysis was
performed as described before.15 TPO concentrations in the
conditioned media were assayed by ELISA. For luciferase assay, each 3 µg of pWTP-luc or pMTP-luc was transfected into L929 cells by
calcium-phosphate method, and luciferase assay was performed as
described before.15
| |
RESULTS |
Serum concentration of TPO.
TPO is believed to be a main cytokine regulating platelet production.
Therefore, it is a primary candidate to contribute to the pathogenesis
of familial ET. We evaluated serum concentrations of TPO in each of the
family members (Fig 1). The nonaffected members manifested normal
levels of TPO,12 whereas the affected members presented
almost 6 to 20 times higher TPO levels.
Hetero-duplex analysis of TPO genome.
We suspected that the elevated TPO levels might be the pathogenic event
leading to familial ET and subsequently examined the integrity of the
TPO gene. To determine whether ET-affected patients harbor
sequence alterations within the TPO gene, we first performed hetero-duplex analysis of genomic DNA. All exons of the TPO
gene were amplified as described in Materials and Methods. A DNA sample from FT-2 was amplified by specific primers, and a DNA sample from a
healthy volunteer was concomitantly amplified as a normal control. PCR
products of segment 2 of the TPO genome formed hetero-duplexes (Fig 2B), but no hetero-duplex bands were detected in other segments (data not shown). Moreover, hetero-duplex bands were observed not only
when PCR products of FT-2 and a healthy volunteer were mixed (Fig 2B,
lane 2), but also in a sample of FT-2 alone (Fig 2B, lane 3). These
results indicate that the TPO gene of FT-2 may be heterozygous,
with one allele being wild-type and the other mutated. To elucidate
whether hetero-duplex formation was linked to the occurrence of
thrombocytosis, we examined the status of segment 2 in all family
members, except for FT-1. Hetero-duplex bands were observed only in
ET-affected family members (Fig 2C).
Identification of a TPO gene mutation.
Sequence analysis of amplified DNA showed one-base deletion in the
5-UTR of the TPO gene. On the mutated allele, a guanine at
nucleotide 325210 was deleted (Fig 2D). This guanine is
located 47 bases upstream of the authentic initiation codon. This
mutation was common in all the affected family members, but was not
present in unaffected healthy family members.
Increased TPO production by mutant TPO cDNA.
We speculated that the identified mutation might increase TPO gene
expression, because the identified mutation resided in the 5-UTR of
the TPO cDNA and did not alter the coding sequence of
TPO gene. Thus, we constructed TPO expression vectors with the
TPO cDNA downstream of the  -actin promoter. The vector
bearing wild-type TPO cDNA was named pAct-wTPO, and the vector
bearing the mutation was named pAct-mTPO. After transient transfection of these vectors into L929 cells, TPO levels in the culture media were
analyzed by ELISA. The level of TPO mRNA was similar in the cells transfected with pAct-wTPO or with pAct-mTPO (Fig
3A). However, TPO levels in the media were
elevated almost 10 times in pAct-mTPO-transfected cells as compared
with pAct-wTPO-transfected cells (Fig 3B). These findings support the
notion that the identified mutation may lead to enhanced TPO
expression. In addition, this elevation seems to result from a
posttranscriptional regulatory mechanism. To further elucidate the
mechanism, we performed in vitro transcription-translation assay of
TPO cDNA in rabbit reticulocyte lysates. As a result, we
observed no significant difference in the amount of final TPO products
between wild-type and mutated-type TPO cDNA (data not shown).
View larger version (53K):
[in this window]
[in a new window]
View larger version (23K):
[in this window]
[in a new window]
| Fig 3.
(A) Mutant-type TPO manifested the same level of
TPO mRNA as wild-type. L929 cells were transfected with 10 µg
of pActC, pAct-wTPO, or pAct-mTPO, respectively. By Northern blot
analysis, TPO mRNA level in the transfected cells showed no
definite difference between pAct-wTPO and pAct-mTPO. (B) TPO production
definitely differed between pAct-wTPO and pAct-mTPO. TPO concentration
in the conditioned media was analyzed by ELISA. TPO released by
pAct-wTPO transfected L929 cells was arbitrarily assigned to a value of
1.0, and the results are shown as the mean ± SD. The analysis was
performed in duplicate assays and the results were reproducible.
|
|
Luciferase assay.
We next examined whether the restricted region of TPO gene
could affect gene expression. TPO-luciferase fusion genes were constructed. The 5-UTR and initial 30 bases of the coding region of
TPO cDNA were cloned upstream of the full-length
luciferase gene. This fusion gene was then inserted downstream
of the SV40 late promoter. The vector bearing wild-type TPO
cDNA was named pWTP-luc, and the vector bearing the mutation was named
pMTP-luc. After transfection of either pWTP-luc or pMTP-luc into L929
cells, luciferase activity was analyzed. As expected, pMTP-luc
manifested almost 5 times higher luciferase activity than pWTP-luc (Fig
4). This result suggested that the
restricted region of the TPO gene may be critical to regulate
TPO gene expression.
View larger version (34K):
[in this window]
[in a new window]
| Fig 4.
A restricted region within the TPO gene affects
heterologous gene expression. L929 cells were transfected with 3 µg
of pWTP-luc or pMTP-luc, respectively. Luciferase assay was performed
as described in Materials and Methods. Luciferase activity of pWTP-luc
was assigned to a value of 1.0, and the results are shown as the mean ± SD. The analysis was performed in duplicate assays and the results were reproducible.
|
|
| |
DISCUSSION |
TPO is believed to be a critical cytokine to regulate platelet
production, and platelet production depends mostly on the TPO-c-Mpl system. Either c-Mpl- or TPO-deficient mice exhibited a greater than
80% decrease in their platelet count,16-18 and
TPO-transgenic mice displayed a marked elevation of platelet
count.19 In this study, we observed that serum levels of
TPO were markedly elevated only in the affected members of familial ET.
These findings suggested that the elevation of TPO contributes to the
pathogenesis of the disease. One-base deletion in the 5-UTR of the
TPO gene was identified only in the ET-affected family members.
Furthermore, we showed that this mutation of the TPO gene
directly increased the production of TPO. Collectively, these findings
strongly suggest that the identified mutation could be the molecular
cause of this case of familial ET.
The TPO gene was cloned in 1994 by several
groups.5-7,10,11,13,14 It has structural homology
to erythropoietin (EPO). Both the EPO receptor and TPO receptor, c-Mpl,
belong to the cytokine superfamily.20,21 As with familial
ET, a few cases of familial polycythemia have been reported. Patients
show lineage-specific proliferation of erythrocytes, which is
transmitted by autosomal-dominant inheritance.22,23
Affected family members carry structural alterations of the EPO
receptor gene, which result in increased sensitivity of the EPO
receptor.24,25 In our case of familial ET, no mutations
were detected in the coding sequence of the c-Mpl gene (data
not shown). Thus, the mechanism causing familial ET in this particular
case seems to be completely different from that of familial
polycythemia.
Although TPO is believed to be an essential cytokine to maintain
platelet count, the precise relationship between TPO production and
platelet count under pathologic conditions has not been fully elucidated. TPO is produced mainly by liver and kidney, and the levels
of TPO mRNA in these organs are found to be constant,
regardless of the thrombocytopenic state. Consequently, a model has
been proposed in which circulating TPO is wasted by c-Mpl expressed by
platelets and megakaryocytes. Accordingly, elevation of serum TPO
levels in thrombocytopenic state is due to the decreased expression of
c-Mpl.26,27 Based on our findings, we suggest that the
5-UTR of the TPO gene may be crucial to regulate TPO gene
expression, probably through a posttranscriptional mechanism. As
previously reported for several genes, such as
bcl-228 or ferritin,29 the
5-UTR contributes to the regulation of gene expression. In some
genes,28 the upstream open reading frame attenuates the
efficiency of translation. The TPO gene also harbors upstream open reading frames. For other genes,29 a regulatory
molecule should exist that could exert its effect by interacting with
5-UTR of mRNA. Considering the structure of 5-UTR of TPO
gene, we suppose that it may play a role in regulating TPO production
by posttranscriptional mechanism. At this point, in vitro
transcription-translation assay did not show any difference in
translation efficiency between wild-type and mutant-type of TPO
cDNA. Therefore, we speculate that additional factors regulating TPO
production may be involved.
A recent study reported almost normal or slightly elevated serum
concentrations of TPO in sporadic ET patients despite increased thrombopoiesis. This was thought to be a consequence of marked decrease
of c-Mpl expression on pathological platelets.30 Thus, the
question arises as to whether the molecular mechanism causing familial
ET may be different from that of sporadic ET. Analysis of two cases of
sporadic ET showed no mutations within the 5-UTR of the TPO
gene (data not shown). Furthermore, considering previous reports,12,30 the level of serum TPO in familial ET seems
to be much higher than in sporadic cases. Collectively, in familial ET,
elevated TPO production may constitute the primary event, and the
proliferation of megakaryocyte lineage should be a secondary event.
Thus, the myeloproliferative state may not be clonal, and the affected
patients are not clinically distinguishable from sporadic cases of ET.
In conclusion, familial ET may represent an independent entity within
myeloproliferative disorders of the megakaryocyte lineage. Most
recently, Wiestner et al31 reported that hereditary
thrombocythemia accompanied by marked elevation of TPO production
occurred as the consequence of exon skipping in the TPO gene.
The exon containing the region of the mutation described here was
skipped out by the mutation of splice donor site.31
Collectively, these findings further support the notion that this
particular region of the TPO gene may be important for the
regulation of TPO expression.
| |
FOOTNOTES |
Submitted December 30, 1997;
accepted May 21, 1998.
Address reprint requests to Takeshi Kondo, MD, PhD, Third Department of
Internal Medicine, Hokkaido University School of Medicine, Kita 15 Nishi 7, Kita-ku, Sapporo, Hokkaido 060-8038, Japan; e-mail: t-kondoh{at}med.hokudai.ac.jp.
The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" is accordance with 18 U.S.C. section 1734 solely to indicate this fact.
| |
ACKNOWLEDGMENT |
The authors thank Drs T. Taniguchi, N. Tanaka (Tokyo University), H. Shibuya (Okazaki National Research Institute), and M. Kitagawa (Yale
University) for invaluable advice; Drs T. Kato and H. Miyazaki (Kirin
Brewery Co) for technical support to measure serum concentration of
TPO; Drs M. Musashi (Hokkaido University), T. Fukuhara (Asahikawa City
Hospital), N. Fujimoto, T. Miyagishima (Kushiro Rosai Hospital), and H. Naruse (Wakkanai Municipal Hospital) for blood sampling; and M. Yanome
for secretarial assistance in preparing the manuscript.
| |
REFERENCES |
1.
Fickers M,
Speck B:
Thrombocythaemia. Familial occurrence and transition into blastic crisis.
Acta Haematol
51:257,
1974[Medline]
[Order article via Infotrieve]
2.
Eyster ME,
Saletan SL,
Rabellino EM,
Karanas A,
McDonald TP,
Locke LA,
Luderer JR:
Familial essential thrombocythemia.
Am J Med
80:497,
1986[Medline]
[Order article via Infotrieve]
3.
Kikuchi M,
Tayama T,
Hayakawa H,
Takahashi I,
Hoshino H,
Ohsaka A:
Familial thrombocytosis.
Br J Haematol
89:900,
1995[Medline]
[Order article via Infotrieve]
4.
Kaushansky K:
Thrombopoietin: The primary regulator of platelet production.
Blood
86:419,
1995[Free Full Text]
5.
de Sauvage FJ,
Hass PE,
Spencer SD,
Malloy BE,
Gurney AL,
Spencer SA,
Darbonne WC,
Henzel WJ,
Wong SC,
Kuang WJ,
Oles KJ,
Hultgren B,
Solberg LA Jr,
Goeddel DV,
Eaton DL:
Stimulation of megakaryocytopoiesis and thrombopoiesis by the c-Mpl ligand.
Nature
369:533,
1994[Medline]
[Order article via Infotrieve]
6.
Lok S,
Kaushansky K,
Holly RD,
Kuijper JL,
Lofton-Day CE,
Oort PJ,
Grant FJ,
Heipel MD,
Burkhead SK,
Kramer JM,
Bell LA,
Sprecher CA,
Blumberg H,
Johnson R,
Prunkard D,
Ching AFT,
Mathewes SL,
Bailey MC,
Forstrom JW,
Buddle MM,
Osborn SG,
Evans SJ,
Sheppard PO,
Presnell SR,
O'Hara PJ,
Hagen FS,
Roth GJ,
Foster DC:
Cloning and expression of murine thrombopoietin cDNA and stimulation of platelet production in vivo.
Nature
369:565,
1994[Medline]
[Order article via Infotrieve]
7.
Bartley TD,
Bogenberger J,
Hunt P,
Li YS,
Lu HS,
Martin F,
Chang MS,
Samal B,
Nichol JL,
Swift S,
Johnson MJ,
Hsu RY,
Parker VP,
Suggs S,
Skrine JD,
Merewether LA,
Clogston C,
Hsu E,
Hokom MM,
Hornkohl A,
Choi E,
Pangelinan M,
Sun Y,
Mar V,
McNinch J,
Simonet L,
Jacobsen F,
Xie C,
Shutter J,
Chute H,
Basu R,
Selander L,
Trollinger D,
Sieu L,
Padilla D,
Trail G,
Elliott G,
Izumi R,
Covey T,
Crouse J,
Garcia A,
Xu W,
Del Castillo J,
Biron J,
Cole S,
Hu MCT,
Pacifici R,
Ponting I,
Saris C,
Wen D,
Yung YP,
Lin H,
Bosselman RA:
Identification and cloning of a megakaryocyte growth and development factor that is a ligand for the cytokine receptor Mpl.
Cell
77:1117,
1994[Medline]
[Order article via Infotrieve]
8.
Kaushansky K,
Lok S,
Holly RD,
Broudy VC,
Lin N,
Bailey MC,
Forstrom JW,
Buddle MM,
Oort PJ,
Hagen FS,
Roth GJ,
Papayannoupoulou T,
Foster DC:
Promotion of megakaryocyte progenitor expansion and differentiation by the c-MPL ligand thrombopoietin.
Nature
369:568,
1994[Medline]
[Order article via Infotrieve]
9.
Wendling F,
Maraskovsky E,
Debili N,
Florindo C,
Teepe M,
Titeux M,
Methia N,
Breton-Gorius J,
Cosman D,
Vainchenker W:
c-Mpl ligand is a humoral regulator of megakaryopoiesis.
Nature
369:571,
1994[Medline]
[Order article via Infotrieve]
10.
Sohma Y,
Akahori H,
Seki N,
Hori T,
Ogami K,
Kato T,
Shimada Y,
Kawamura K,
Miyazaki H:
Molecular cloning and chromosomal localization of the human thrombopoietin.
FEBS Lett
353:57,
1994[Medline]
[Order article via Infotrieve]
11.
Foster DC,
Sprecher CA,
Grant FJ,
Kramer JM,
Kuijper JL,
Holly RD,
Whitmore TE,
Heipel MD,
Bell LA,
Ching AFT,
McGrane V,
Hart C,
O'Hara PJ,
Lok S:
Human thrombopoietin: Gene structure, cDNA sequence, expression, and chromosomal localization.
Proc Natl Acad Sci USA
91:13023,
1994[Abstract/Free Full Text]
12.
Tahara T,
Usuki K,
Sato H,
Ohashi H,
Morita H,
Tsumura H,
Matsumoto A,
Miyazaki H,
Urabe A,
Kato T:
A sensitive sandwich ELISA for measuring thrombopoietin in human serum: Serum thrombopoietin levels in healthy volunteers and in patients with haemopoietic disorders.
Br J Haematol
93:783,
1996[Medline]
[Order article via Infotrieve]
13.
Gurney AL,
Kuang WJ,
Xie MH,
Malloy BE,
Eaton DL,
de Sauvage FJ:
Genomic structure, chromosomal localization, and conserved alternative splice forms of thrombopoietin.
Blood
85:981,
1995[Abstract/Free Full Text]
14.
Chang MS,
McNinch J,
Basu R,
Shutter J,
Hsu RY,
Perkins C,
Mar V,
Suggs S,
Welcher A,
Li L,
Lu H,
Bartley T,
Hunt P,
Martin F,
Samal B,
Bogenberger J:
Cloning and characterization of the human megakaryocyte growth and development factor (MGDF) gene.
J Biol Chem
270:511,
1995[Abstract/Free Full Text]
15.
Kondo T,
Minamino N,
Nagamura-Inoue T,
Matsumoto M,
Taniguchi T,
Tanaka N:
Identification and characterization of nucleophosmin/B23/numatrin which binds the anti-oncogenic transcription factor IRF-1 and manifests oncogenic activity.
Oncogene
15:1275,
1997[Medline]
[Order article via Infotrieve]
16.
Gurney AL,
Carver-Moore K,
de Sauvage FJ,
Moore MW:
Thrombocytopenia in c-mpl-deficient mice.
Science
265:1445,
1994[Abstract/Free Full Text]
17.
Alexander WS,
Roberts AW,
Nicola NA,
Li R,
Metcalf D:
Deficiencies in progenitor cells of multiple hematopoietic lineages and defective megakaryocytopoiesis in mice lacking the thrombopoietic receptor c-Mpl.
Blood
87:2162,
1996[Abstract/Free Full Text]
18.
de Sauvage FJ,
Carver-Moore K,
Luoh SM,
Ryan A,
Dowd M,
Eaton DL,
Moore MW:
Physiological regulation of early and late stages of megakaryocytopoiesis by thrombopoietin.
J Exp Med
183:651,
1996[Abstract/Free Full Text]
19.
Zhou W,
Toombs CF,
Zou T,
Guo J,
Robinson MO:
Transgenic mice overexpressing human c-mpl ligand exhibit chronic thrombocytosis and display enhanced recovery from 5-fluorouracil or antiplatelet serum treatment.
Blood
89:1551,
1997[Abstract/Free Full Text]
20.
Bazan JF:
Structural design and molecular evolution of a cytokine receptor superfamily.
Proc Natl Acad Sci USA
87:6934,
1990[Abstract/Free Full Text]
21.
Vigon I,
Mornon JP,
Cocault L,
Mitjavila MT,
Tambourin P,
Gisselbrecht S,
Souyri M:
Molecular cloning and characterization of MPL, the human homolog of the v-mpl oncogene: Identification of a member of the hematopoietic growth factor superfamily.
Proc Natl Acad Sci USA
87:5640,
1992
22.
Juvonen E,
Ikkala E,
Fyhrquist F,
Ruutu TL:
Autosomal dominant erythrocytosis caused by increased sensitivity to erythropoietin.
Blood
78:3066,
1991[Abstract/Free Full Text]
23.
Emanuel PD,
Eaves CJ,
Broudy VC,
Papayannopoulou T,
Moore MR,
D'Andrea AD,
Prchal JF,
Eaves AC,
Prchal JT:
Familial and congenital polycythemia in three unrelated families.
Blood
79:3019,
1992[Abstract/Free Full Text]
24.
de la Chapelle A,
Traskelin AL,
Juvonen E:
Truncated erythropoietin receptor causes dominantly inherited benign human erythrocytosis.
Proc Natl Acad Sci USA
90:4495,
1993[Abstract/Free Full Text]
25.
Sokol L,
Luhovy M,
Guan Y,
Prchal JF,
Semenza GL,
Prchal JT:
Primary familial polycythemia: A frameshift mutation in the erythropoietin receptor gene and increased sensitivity of erythroid progenitors to erythropoietin.
Blood
86:15,
1995[Abstract/Free Full Text]
26.
Stoffel R,
Wiestner A,
Skoda RC:
Thrombopoietin in thrombocytopenic mice: Evidence against regulation at the mRNA level and for a direct regulatory role of platelets.
Blood
87:567,
1996[Abstract/Free Full Text]
27.
Cohen-Solal K,
Villeval JL,
Titeux M,
Lok S,
Vainchenker W,
Wendling F:
Constitutive expression of Mpl ligand transcripts during thrombocytopenia or thrombocytosis.
Blood
88:2578,
1996[Abstract/Free Full Text]
28.
Harigai M,
Miyashita T,
Hanada M,
Reed JC:
A cis-acting element in the BCL-2 gene controls expression through translational mechanisms.
Oncogene
12:1369,
1996[Medline]
[Order article via Infotrieve]
29.
Harrison PM,
Arosio P:
The ferritins: molecular properties, iron storage function and cellular regulation.
Biochim Biophys Acta
1275:161,
1996[Medline]
[Order article via Infotrieve]
30.
Horikawa Y,
Matsumaura I,
Hashimoto K,
:
Markedly reduced expression of platelet c-mpl peceptor in essential thrombocythemia.
Blood
90:4031,
1997[Abstract/Free Full Text]
31.
Wiestner A,
Schlemper RJ,
van der Maas APC,
Skoda RC:
An activating splice donor mutation in the thrombopoietin gene causes hereditary thrombocythaemia.
Nat Genet
18:49,
1998[Medline]
[Order article via Infotrieve]
 CiteULike  Connotea  Del.icio.us  Digg  Reddit  Technorati What's this?
This article has been cited by other articles:
|
|
|
|
 
B. J. Lannutti, A. Epp, J. Roy, J. Chen, and N. C. Josephson
Incomplete restoration of Mpl expression in the mpl-/- mouse produces partial correction of the stem cell-repopulating defect and paradoxical thrombocytosis
Blood,
February 19, 2009;
113(8):
1778 - 1785.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. Cazzola
Molecular basis of thrombocytosis
Haematologica,
May 1, 2008;
93(5):
646 - 648.
[Full Text]
[PDF]
|
|
|
|
|
|
|
K. Liu, R. Kralovics, Z. Rudzki, B. Grabowska, A. S. Buser, D. Olcaydu, H. Gisslinger, R. Tiedt, P. Frank, K. Okon, et al.
A de novo splice donor mutation in the thrombopoietin gene causes hereditary thrombocythemia in a Polish family
Haematologica,
May 1, 2008;
93(5):
706 - 714.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
L. Teofili, R. Foa, F. Giona, and L. M. Larocca
Childhood polycythemia vera and essential thrombocythemia: does their pathogenesis overlap with that of adult patients?
Haematologica,
February 1, 2008;
93(2):
169 - 172.
[Full Text]
[PDF]
|
|
|
|
|
|
|
L. Teofili, F. Giona, M. Martini, T. Cenci, F. Guidi, L. Torti, G. Palumbo, A. Amendola, R. Foa, and L. M. Larocca
Markers of Myeloproliferative Diseases in Childhood Polycythemia Vera and Essential Thrombocythemia
J. Clin. Oncol.,
March 20, 2007;
25(9):
1048 - 1053.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
R. Skoda
The Genetic Basis of Myeloproliferative Disorders
Hematology,
January 1, 2007;
2007(1):
1 - 10.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
A. I. Schafer
Molecular basis of the diagnosis and treatment of polycythemia vera and essential thrombocythemia
Blood,
June 1, 2006;
107(11):
4214 - 4222.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
A. R. Moliterno, D. M. Williams, L. I. Gutierrez-Alamillo, R. Salvatori, R. G. Ingersoll, and J. L. Spivak
Mpl Baltimore: A thrombopoietin receptor polymorphism associated with thrombocytosis
PNAS,
August 3, 2004;
101(31):
11444 - 11447.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
K. Ravid
Activating mutation in the c-MPL gene and FET
Blood,
June 1, 2004;
103(11):
3998 - 3999.
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. Ding, H. Komatsu, A. Wakita, M. Kato-Uranishi, M. Ito, A. Satoh, K. Tsuboi, M. Nitta, H. Miyazaki, S. Iida, et al.
Familial essential thrombocythemia associated with a dominant-positive activating mutation of the c-MPL gene, which encodes for the receptor for thrombopoietin
Blood,
June 1, 2004;
103(11):
4198 - 4200.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
A. I. Schafer
Thrombocytosis
N. Engl. J. Med.,
March 18, 2004;
350(12):
1211 - 1219.
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. L. Spivak
Polycythemia vera: myths, mechanisms, and management
Blood,
December 15, 2002;
100(13):
4272 - 4290.
[Full Text]
[PDF]
|
|
|
|
|
|
|
R. A. Mesa, C. A. Hanson, C.-Y. Li, S.-Y. Yoon, S. V. Rajkumar, G. Schroeder, and A. Tefferi
Diagnostic and prognostic value of bone marrow angiogenesis and megakaryocyte c-Mpl expression in essential thrombocythemia
Blood,
May 13, 2002;
99(11):
4131 - 4137.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. Cazzola and R. C. Skoda
Translational pathophysiology: a novel molecular mechanism of human disease
Blood,
June 1, 2000;
95(11):
3280 - 3288.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
N. Ghilardi and R. C. Skoda
A Single-Base Deletion in the Thrombopoietin (TPO) Gene Causes Familial Essential Thrombocythemia Through a Mechanism of More Efficient Translation of TPO mRNA
Blood,
August 15, 1999;
94(4):
1480 - 1482.
[Full Text]
[PDF]
|
|
|
|
|
|
|
S. D. Nimer
Essential Thrombocythemia: Another "Heterogeneous Disease" Better Understood?
Blood,
January 15, 1999;
93(2):
415 - 416.
[Full Text]
[PDF]
|
|
|
|
|
|
|
C. N. Harrison, R. E. Gale, S. J. Machin, and D. C. Linch
A Large Proportion of Patients With a Diagnosis of Essential Thrombocythemia Do Not Have a Clonal Disorder and May Be at Lower Risk of Thrombotic Complications
Blood,
January 15, 1999;
93(2):
417 - 424.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
Abstract
Introduction
Abstract