notch1
Gene
TABLE 7.5
Core Components of the Notch Pathway in the Development of Germ Layers and the Dorsal Midline in Xenopus
See abbreviations in Table 7.3 legend.
Expression
Gain-of-Function
Loss-of-Function
Role/Details
(Dominant-Negative/Morpholino)
notch1 is expressed in the IMZ and NIMZ during
gastrulation ( López et al., 2003 ; Miazga and
McLaughlin, 2009 ).
Germ layers:
Balanced Notch1 signaling is required for delimiting the
three germ layers and normal morphogenetic
movements during gastrulation. Cell-fate choice upon
activation of Notch signaling does not depend on
proliferation during gastrulation.
DML:
Among the DML precursors, notch1 favors FP and
hypochord development at the expense of the notochord.
Germ layers:
notch1ΔE +/− HUA at gastrula stage, analysis at tailbud stage :
↑
neural, and muscle tissues ( Coffman et al., 1993 ).
epidermal,
notch1ΔE (animal caps): ↑ectodermal response to neural induction;
prolonged ectodermal competence for mesodermal induction
beyond the onset of gastrulation ( Coffman et al., 1993 ).
Mouse NICD1, analysis at tailbud stage: ↓myosin (muscle
differentiation marker) ( Kopan et al., 1994 ).
GR-NICD1, Dex NF2, but not Dex NF12: ↑neural plate (sox2; late
neurula, NF18/19) and muscle tissues (12/101 marker; tailbud,
NF25) ( Glavic et al., 2004 ).
GR-NICD1 or GR-RBPJ-VP16, Dex NF10 or 12, analysis at late
neurula/tailbud stages : ↑endodermal ↓mesodermal derivatives
( Contakos et al., 2005 ).
GR-RBPJ-VP16, Dex NF14, analysis at late neurula/tailbud
stages : ↓endodermal ↑mesodermal derivatives ( Contakos et al.,
2005 ).
NICD1, analysis at gastrula stages:
DMZ-directed injection: delayed blastopore formation and
closure; ↓mesoderm (tbxt), ↑neural ectoderm (sox2) ↑suprablastoporal endoderm (sox17).
Dorsal/animal-directed injection: tbxt domain expanded but more
diffuse, probably due to ectopic prolonged competence for
mesodermal induction in the ectoderm ( Revinski et al., 2010 ).
DML:
notch1ΔE +/− HUA at gastrula stage: ↓notochord (tailbud stage)
( Coffman et al., 1993 ).
NICD1:
Analysis at gastrula stage: ↓GO mesoderm (chrd), ↑ presumptive
FP (hes4) ( López et al., 2003 ), ( López et al., 2005 ).
Analysis at neurula stage: ↓notochord (chrd, tbxt), ↑FP (shh,
foxa4) ( López et al., 2003 ).
Analysis at tadpole stages: ↑hypochord (vegf, spon1, NF25,38)
( Peyrot et al., 2011 ).
GR-NICD1/time-controlled experiments with Dex: higher
susceptibility to ↑FP and ↓notochord in the f rst than in the
second half of gastrulation ( López et al., 2003 )
Germ layers:
GR-RBPJ DBM, Dex NF 10 or 12, analysis at late neurula/
tailbud stages: reduced endodermal, expanded mesodermal
derivatives ( Contakos
et al., 2005 ).
GR-RBPJ DBM, Dex NF14, analysis at late neurula/tailbud
stages: expanded endodermal, reduced mesodermal
derivatives ( Contakos et al., 2005 ).
notch1 MO (dorsal injections), analysis at gastrula stage:
delayed blastopore formation and closure, expanded the
mesoderm (tbxt), animally shifted the neural-ectoderm
(sox2), reduced the supra-blastoporal endoderm (sox17)
( Revinski et al., 2010 ).
DML:
notch1 MO: expanded the notochord ( chrd+ cells, neurula
stage) ( López et al., 2003 ).
92
Xenopus
Gene
TABLE 7.5
Core Components of the Notch Pathway in the Development of Germ Layers and the Dorsal Midline in Xenopus
See abbreviations in Table 7.3 legend.
Expression
Gain-of-Function
Loss-of-Function
Role/Details
(Dominant-Negative/Morpholino)
notch1 is expressed in the IMZ and NIMZ during
gastrulation ( López et al., 2003 ; Miazga and
McLaughlin, 2009 ).
Germ layers:
Balanced Notch1 signaling is required for delimiting the
three germ layers and normal morphogenetic
movements during gastrulation. Cell-fate choice upon
activation of Notch signaling does not depend on
proliferation during gastrulation.
DML:
Among the DML precursors, notch1 favors FP and
hypochord development at the expense of the notochord.
Germ layers:
notch1ΔE +/− HUA at gastrula stage, analysis at tailbud stage :
↑
neural, and muscle tissues ( Coffman et al., 1993 ).
epidermal,
notch1ΔE (animal caps): ↑ectodermal response to neural induction;
prolonged ectodermal competence for mesodermal induction
beyond the onset of gastrulation ( Coffman et al., 1993 ).
Mouse NICD1, analysis at tailbud stage: ↓myosin (muscle
differentiation marker) ( Kopan et al., 1994 ).
GR-NICD1, Dex NF2, but not Dex NF12: ↑neural plate (sox2; late
neurula, NF18/19) and muscle tissues (12/101 marker; tailbud,
NF25) ( Glavic et al., 2004 ).
GR-NICD1 or GR-RBPJ-VP16, Dex NF10 or 12, analysis at late
neurula/tailbud stages : ↑endodermal ↓mesodermal derivatives
( Contakos et al., 2005 ).
GR-RBPJ-VP16, Dex NF14, analysis at late neurula/tailbud
stages : ↓endodermal ↑mesodermal derivatives ( Contakos et al.,
2005 ).
NICD1, analysis at gastrula stages:
DMZ-directed injection: delayed blastopore formation and
closure; ↓mesoderm (tbxt), ↑neural ectoderm (sox2) ↑suprablastoporal endoderm (sox17).
Dorsal/animal-directed injection: tbxt domain expanded but more
diffuse, probably due to ectopic prolonged competence for
mesodermal induction in the ectoderm ( Revinski et al., 2010 ).
DML:
notch1ΔE +/− HUA at gastrula stage: ↓notochord (tailbud stage)
( Coffman et al., 1993 ).
NICD1:
Analysis at gastrula stage: ↓GO mesoderm (chrd), ↑ presumptive
FP (hes4) ( López et al., 2003 ), ( López et al., 2005 ).
Analysis at neurula stage: ↓notochord (chrd, tbxt), ↑FP (shh,
foxa4) ( López et al., 2003 ).
Analysis at tadpole stages: ↑hypochord (vegf, spon1, NF25,38)
( Peyrot et al., 2011 ).
GR-NICD1/time-controlled experiments with Dex: higher
susceptibility to ↑FP and ↓notochord in the f rst than in the
second half of gastrulation ( López et al., 2003 )
Germ layers:
GR-RBPJ DBM, Dex NF 10 or 12, analysis at late neurula/
tailbud stages: reduced endodermal, expanded mesodermal
derivatives ( Contakos
et al., 2005 ).
GR-RBPJ DBM, Dex NF14, analysis at late neurula/tailbud
stages: expanded endodermal, reduced mesodermal
derivatives ( Contakos et al., 2005 ).
notch1 MO (dorsal injections), analysis at gastrula stage:
delayed blastopore formation and closure, expanded the
mesoderm (tbxt), animally shifted the neural-ectoderm
(sox2), reduced the supra-blastoporal endoderm (sox17)
( Revinski et al., 2010 ).
DML:
notch1 MO: expanded the notochord ( chrd+ cells, neurula
stage) ( López et al., 2003 ).
92
Xenopus