93
RBPJ
psen
DML:
DAPT (Ὑ-secretase inhibitor): delayed the convergentὙ-secretase is necessary to keep the morphogenetic
extension movements typical of the notochordal cells
movements at a normal pace during gastrulation.
during gastrulation ( Revinski
et al., 2010 ).
Both RBPJ.S variants (see Table 7.1) are expressed
ubiquitously from the unfertilized egg to the tailbud
stage, but RBPJ.S-v2 transcripts are more abundant
before gastrulation (Wettstein et al., 1997) (Ito et al.,
2007b ).
Germ layers:
RBPJ-dependent signaling favors the development of
endoderm-derived cell types and disfavors the
development of mesoderm-derived cell types during
gastrulation but plays the opposite role since the neural
plate stage.
A critical time window that comprises gastrulation and
ends at the onset of neurulation was described in
particular for cardiac mesoderm specif cation, which is
disfavored by Notch/RBPJ signaling during this period.
Germ layers:
GR-RBPJ-VP16, analysis at late neurula and tailbud stages:
Dex NF10 or 12: ↑markers of endodermal-derived cell types,
↓
of
markers mesodermal-derived cell types (paraxial,
intermediate, and cardiac mesoderm).
Dex NF14: ↓markers of endodermal-derived cell types, slightly
↑
of intermediate
markers
mesoderm-derived cell types.
Cardiac mesoderm unaffected (Contakos et al., 2005 ).
GR-RBPJ-VP16 (Dex NF10) +/ER-RBPJ DBM (E2 at NF10, 14, 15, 16); ISH of the cardiac f eld
marker nkx2.5 at tailbud stage: the loss of nkx2.5 induced by
activating Notch/RBPJ signaling at the onset of gastrulation
was rescued by blocking Notch/RBPJ during gastrulation.
This rescuing ability was gradually lost after the onset of
neurulation (Miazga and McLaughlin, 2009).
GR-RBPJ-VP16 (Dex NF10): ↓gata4 (mid-gastrula) (Miazga
and McLaughlin, 2009).
Germ layers:
GR-RBPJ DBM, analysis at late neurula and tailbud stages:
Dex NF10 or 12: ↓markers of endodermal-derived cell types,
↑
of
markers mesodermal-derived cell types (paraxial,
intermediate, and cardiac mesoderm).
Dex NF14 : ↑markers of endodermal-derived cell types,
↓
of intermediate
markers
mesoderm-derived cell types.
Cardiac mesoderm unaffected (Contakos et al., 2005 )
GR-RBPJ DBM (Dex NF10), ISH analysis at NF11–11.5:
precocious induction of heart f eld markers (nkx2–5,
gata4, tbx5) (Miazga and McLaughlin, 2009).
RBPJ DBM, analysis at gastrula stage: mild expansion of tbxt
(pan-mesodermal) and myf5 (presumptive paraxial
mesoderm) domains, variable ↓ and animal shift of sox2,
variable results of sox17 expression (endoderm) ( Revinski
et al., 2010 ).
RBPJ DBM, analysis at neural plate stage: mild tendency to
↑
mesoderm markers
paraxial
myf5 and myoD and ↓neural
marker sox2 ( Revinski et al., 2010 ).
RBPJ.S v2 MO: abnormal gastrulation, neural fold disorganization,
↓
markers
mesodermal
tbxt, myod1, ventx1.2, chrd, but not gsc
(RT-sqPCR, NF 10.5). ↓tbxt in the IMZ (ISH). This effect was
not rescued by NICD1 or DN-hes5.1 ( Ito et al., 2007a ).
RBPJ.S-v1 MO : no morphological defects, no changes in
molecular markers ( Ito et al., 2007a ). Probably due to
compensation by the other homeolog as neither MO used in
this study is predicted to knock-down RBPJ.L.
DML:
RBPJ DBM: ↑chrd+ in the GO and chrd+ notochord expression
in neurula; ↓FP (foxa4+/shh+ cells) (neurula)( López et al.,
2003 ); ↓hypochord (vegf, spon) (NF28/35) (ISH) ( Peyrot et al.,
2011 ).
(Continued)
Notch Signaling in Early Embryogenesis
RBPJ
psen
DML:
DAPT (Ὑ-secretase inhibitor): delayed the convergentὙ-secretase is necessary to keep the morphogenetic
extension movements typical of the notochordal cells
movements at a normal pace during gastrulation.
during gastrulation ( Revinski
et al., 2010 ).
Both RBPJ.S variants (see Table 7.1) are expressed
ubiquitously from the unfertilized egg to the tailbud
stage, but RBPJ.S-v2 transcripts are more abundant
before gastrulation (Wettstein et al., 1997) (Ito et al.,
2007b ).
Germ layers:
RBPJ-dependent signaling favors the development of
endoderm-derived cell types and disfavors the
development of mesoderm-derived cell types during
gastrulation but plays the opposite role since the neural
plate stage.
A critical time window that comprises gastrulation and
ends at the onset of neurulation was described in
particular for cardiac mesoderm specif cation, which is
disfavored by Notch/RBPJ signaling during this period.
Germ layers:
GR-RBPJ-VP16, analysis at late neurula and tailbud stages:
Dex NF10 or 12: ↑markers of endodermal-derived cell types,
↓
of
markers mesodermal-derived cell types (paraxial,
intermediate, and cardiac mesoderm).
Dex NF14: ↓markers of endodermal-derived cell types, slightly
↑
of intermediate
markers
mesoderm-derived cell types.
Cardiac mesoderm unaffected (Contakos et al., 2005 ).
GR-RBPJ-VP16 (Dex NF10) +/ER-RBPJ DBM (E2 at NF10, 14, 15, 16); ISH of the cardiac f eld
marker nkx2.5 at tailbud stage: the loss of nkx2.5 induced by
activating Notch/RBPJ signaling at the onset of gastrulation
was rescued by blocking Notch/RBPJ during gastrulation.
This rescuing ability was gradually lost after the onset of
neurulation (Miazga and McLaughlin, 2009).
GR-RBPJ-VP16 (Dex NF10): ↓gata4 (mid-gastrula) (Miazga
and McLaughlin, 2009).
Germ layers:
GR-RBPJ DBM, analysis at late neurula and tailbud stages:
Dex NF10 or 12: ↓markers of endodermal-derived cell types,
↑
of
markers mesodermal-derived cell types (paraxial,
intermediate, and cardiac mesoderm).
Dex NF14 : ↑markers of endodermal-derived cell types,
↓
of intermediate
markers
mesoderm-derived cell types.
Cardiac mesoderm unaffected (Contakos et al., 2005 )
GR-RBPJ DBM (Dex NF10), ISH analysis at NF11–11.5:
precocious induction of heart f eld markers (nkx2–5,
gata4, tbx5) (Miazga and McLaughlin, 2009).
RBPJ DBM, analysis at gastrula stage: mild expansion of tbxt
(pan-mesodermal) and myf5 (presumptive paraxial
mesoderm) domains, variable ↓ and animal shift of sox2,
variable results of sox17 expression (endoderm) ( Revinski
et al., 2010 ).
RBPJ DBM, analysis at neural plate stage: mild tendency to
↑
mesoderm markers
paraxial
myf5 and myoD and ↓neural
marker sox2 ( Revinski et al., 2010 ).
RBPJ.S v2 MO: abnormal gastrulation, neural fold disorganization,
↓
markers
mesodermal
tbxt, myod1, ventx1.2, chrd, but not gsc
(RT-sqPCR, NF 10.5). ↓tbxt in the IMZ (ISH). This effect was
not rescued by NICD1 or DN-hes5.1 ( Ito et al., 2007a ).
RBPJ.S-v1 MO : no morphological defects, no changes in
molecular markers ( Ito et al., 2007a ). Probably due to
compensation by the other homeolog as neither MO used in
this study is predicted to knock-down RBPJ.L.
DML:
RBPJ DBM: ↑chrd+ in the GO and chrd+ notochord expression
in neurula; ↓FP (foxa4+/shh+ cells) (neurula)( López et al.,
2003 ); ↓hypochord (vegf, spon) (NF28/35) (ISH) ( Peyrot et al.,
2011 ).
(Continued)
Notch Signaling in Early Embryogenesis