|
|
 Previous Article | Table of Contents | Next Article 
Blood, 15 March 2001, Vol. 97, No. 6, pp. 1653-1661
HEMATOPOIESIS
Characterization of Mpl mutants using primary
megakaryocyte-lineage cells from mpl /
mice: a new system for Mpl structure-function studies
Meenakshi Gaur,
George J. Murphy,
Frederic J. deSauvage, and
Andrew D. Leavitt
From the Departments of Laboratory and Internal
Medicine, University of California, San Francisco, and the Department
of Molecular Oncology, Genentech, San Francisco, CA.
Mpl is the thrombopoietin (TPO) receptor. The current molecular
understanding of how Mpl activation stimulates proliferation of
megakaryocyte-lineage cells is based largely on the engineered expression of Mpl in nonmegakaryocyte-lineage cell lines. However, the
relevance of these findings to Mpl signaling in primary
megakaryocyte-lineage cells remains largely unknown. Therefore, a
system was developed to study Mpl function in primary
mpl / megakaryocyte-lineage cells.
Expressing avian retroviral receptors on the surfaces of mammalian
cells overcomes their natural block to avian retroviral infection; 815 bp of human GPIIb regulatory sequence was used to generate transgenic
mice with megakaryocyte-lineage expression of the subgroup A avian
leukosis virus receptor, TVA. Avian retroviral infection of
unfractionated bone marrow from these mice is restricted to
megakaryocyte-lineage cells. The transgenic mice were crossed to an
mpl/ background generating
GPIIb-tva+mpl/ mice. By using
avian retroviruses to express wild-type or mutant Mpl on the surfaces
of primary megakaryocyte-lineage cells, it was demonstrated that (1)
the 10 membrane-proximal, cytoplasmic amino acids of Mpl are required
for TPO-induced proliferation; (2) Y582F mutation confers a
proliferative advantage over wild-type Mpl and imparts a constitutive
anti-apoptotic signal; (3) truncating the 50 C-terminal Mpl amino acids
reduces but does not eliminate TPO-induced mitogen-activated
protein kinase activation, yet it does not alter the synergistic effect
of stem cell factor on TPO-induced proliferation; and (4) TPO-induced
proliferation of early, primary megakaryocyte-lineage cells does not
require Stat-5 phosphorylation. The system reported provides an
improved approach for Mpl structure-function studies, and the method
can be applied to any hematopoietic lineage.
 CiteULike  Connotea  Del.icio.us  Digg  Reddit  Technorati What's this?
This article has been cited by other articles:
|
|
|
|
 
C. M. Rudin, J. L. Marshall, C. H. Huang, H. L. Kindler, C. Zhang, D. Kumar, P. C. Gokhale, J. Steinberg, S. Wanaski, U. N. Kasid, et al.
Delivery of a Liposomal c-raf-1 Antisense Oligonucleotide by Weekly Bolus Dosing in Patients with Advanced Solid Tumors: A Phase I Study
Clin. Cancer Res.,
November 1, 2004;
10(21):
7244 - 7251.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
T. Kamata, C. A. Pritchard, and A. D. Leavitt
Raf-1 is not required for megakaryocytopoiesis or TPO-induced ERK phosphorylation
Blood,
April 1, 2004;
103(7):
2568 - 2570.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
C. Meunier, D. Bordereaux, F. Porteu, S. Gisselbrecht, S. Chretien, and G. Courtois
Cloning and Characterization of a Family of Proteins Associated with Mpl
J. Biol. Chem.,
March 8, 2002;
277(11):
9139 - 9147.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
