Cell Signaling During Primitive Hematopoiesis
445
be identifed in zebrafsh blood develop-
ment mutants, now that the zebrafsh
genome is nearly completely sequenced.
Embryological ‘‘cut and paste’’ experi-
m
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sa
sw
e
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la
sp
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pathways in nonhematopoietic cells by
numerous means have Further revealed
a complex and dynamic role For cell–cell
signaling in regulating hematopoietic cell
specifcation, potential (defnitive or prim-
itive), cell survival, and diFFerentiation. In
spite oF a tremendous amount oF recent
progress in understanding how primi-
tive hematopoiesis is regulated, there is
still a long way to go. ±irst, the molec-
ular profle oF primitive progenitors, and
precursors at discrete stages oF the diFFer-
entiation process must be characterized.
With the availability oF techniques such
as gene expression profling, it should
be possible to identiFy unique markers
For each cell type that will allow For
identiFying and studying them
in situ
.
Moreover, it will help identiFy genes that
determine each cell type’s characteris-
tics. Second, a better characterization oF
cell–cell interactions will help identiFy Fac-
tors that are required For various aspects
oF primitive hematopoiesis. Ultimately,
the goal is to understand all oF the sig-
naling pathways that regulate primitive
hematopoiesis. Once genes that regu-
late primitive hematopoiesis are identifed,
determining how they Function within reg-
ulatory pathways will be an essential step
in gaining a complete understanding oF
hematopoiesis.
See also
Biological Regulation by
Protein Phosphorylation; Cellular
Interactions; Developmental Cell
Biology.
Bibliography
Books and Reviews
Amatruda, J.±.,
Zon, L.I.
(1999)
Dissecting
hematopoiesis and disease using the zebrafsh,
Dev. Biol.
216
, 1–15.
Baron, M.
(2001)
Induction
oF
embryonic
hematopoietic and endothelial stem/progeni-
tor
cells
by
hedgehog-mediated
signals,
Differentiation
68
, 175–185.
Evans, T.
(1997)
Developmental
biology
oF
hematopoiesis,
Hematol. Oncol. Clin. North
Am.
11
, 1115–1147.
Galloway, J.L., Zon, L.I. (2003) Ontogeny oF
hematopoiesis: examining the emergence oF
hematopoietic cells in the vertebrate embryo,
Curr. Top. Dev. Biol.
53
, 139–158.
Orkin, S.H.
(1996)
Development
oF
the
hematopoietic system,
Curr. Opin. Genet. Dev.
6
, 597–602.
Orkin, S.H., Zon, L.I. (2002) Hematopoiesis and
stem cells: plasticity versus developmental
heterogeneity,
Nat. Immunol.
3
, 323–328.
Palis, J.,
Segel, G.B.
(1998)
Developmental
biology
oF
erythropoiesis,
Blood
Rev.
12
,
106–114.
Palis, J., Yoder, M.C. (2001) Yolk-sac hematopo-
iesis: the frst blood cells oF mouse and man,
Exp. Hematol.
29
, 927–936.
Shepard, J.L., Zon, L.I. (2000) Developmental
derivation
oF
embryonic
and
adult
macrophages,
Curr. Opin. Hematol.
7
, 3–8.
Yoder, M.C. (2002) Embryonic hematopoiesis in
mice and humans,
Acta Paediatr. Suppl.
91
,
5–8.
Primary Literature
Baron, M.
(2001)
Induction
oF
embryonic
hematopoietic and endothelial stem/progeni-
tor
cells
by
hedgehog-mediated
signals,
Differentiation
68
, 175–185.
BelaoussoFF, M., ±arrington, S.M., Baron, M.H.
(1998) Hematopoietic induction and respeci-
fcation oF A-P identity by visceral endoderm
signaling in the mouse embryo,
Development
125
, 5009–5018.
Bertwistle, D.,
Walmsley, M.E.,
Read, E.M.,
Pizzey, J.A., Patient, R.K. (1996) GATA Factors
and the origins oF adult and embryonic blood
in Xenopus: responses to retinoic acid,
Mech.
Dev.
57
, 199–214.
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