The Expression Profile of NET1 in WT zebrafish embryos

1
The Expression Profile of NET1 in WT zebrafish
embryos
WT 30 Epiboly
WT 50 Epiboly
WT Bud Stage
WT 16 hr

• (a) The Expression Profile of RhoGEF Neuro
  Epithelioma Transforming Gene 1 (NET 1) in Wild
  Type Zebrafish Embryos

2
The Expression Profile of NET1 in MZoep Zebrafish
Embryos
MZoep 30Epiboly
MZoep 24 h

• (b) The Expression Profile of RhoGEF Neuro
  Epithilioma Transforming Gene 1 (NET1) in
  Maternal Zygotic one-eyed pinhead (MZoep)
  Zebrafish Embryos

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Zebrafish RhoGEF Neuro Epithelioma Transforming
Gene 1 (NET1)
NET1-short
NET1-long

• There are two isoforms of NET1 in zebrafish,
  which are arbitrarily called NET1-short and
  NET1-long.

Our RhoGEF is homologous to NET1 in mice and
humans.
NET1-short and NET1-long are both Present during
gastrulation.
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Morpholino-induced Knock Down Experiment with 8
ng NET1-Long Morpholino

• 50 Epiboly WT Zebrafish stained with Hggl, which
  is a marker of the Axial Mesoderm

• 50 Epiboly Zebrafish treated with 8ng NET1-long
  Morpholino stained with Hggl

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Over Expression Experiment with 15 pg full length
NET1-Long mRNA

• 50 Epiboly WT Zebrafish stained with ntl, which
  is a marker of the margin

50 Epiboly Zebrafish injected with 15 pg
NET1-long mRNA stained with ntl
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Discussion

• NET1 is expressed in the prechordal plate. These
  cells are the first to internalize during
  gastrulation.
• We expect that the prechordal plate could cause
  internalization by dragging the rest of the
  margin cells along with it.
• The expression profile of NET1 suggests that NET1
  may be involved in initiating the internal
  movement of mesoderm.
• Expression of NET1 at 30 epiboly before
  internalization also furthers the idea of NET1 as
  an initiator of internalization
• NET1 was not expressed in MZoep mutants that lack
  Nodal signaling, and may be a downstream target
  of Nodal.

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Discussion

• NET1 may help hold cells together because it is
  an activator of RhoA, which causes stress fiber
  formation
• The defects observed when translation of
  NET1-long was blocked in the morpholino
  experiment also points to the role of NET1 in
  cell adhesion. The cells of the axial mesoderm
  were not sticking to the substrate and were very
  diffuse compared to wild type.
• The gaps of expression around in the over
  expression experiment are not a good indicator of
  the function of NET1. The activity of Rho A
  through out the embryo introduces too many
  defects in general.

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Acknowledgments

• Dr. Alexander F. Schier
• Dr. Kathy Joubin
• All of Laboratory 16
• Skirball Institute NYU
• Ms. Anne Manwell
• Stuyvesent High School