Development
What causes cell
differentiation?
Molecular Markers
Homeobox Genes
1. Transcription factors
encoding the DNA binding
homeodomain.
2. Expressed in temporal and
spatial specific patterns
during development.
3. Cell differentiation is
disrupted when they are
mutated.
Adult Spinal Cord
Neural Tube Development
How are the
expression
patterns for
homeodomain
proteins
created?
Lbx1 Expression Pattern
Pax3•Lbx1
Project Goal
Identify the tissue specific enhancer that
creates the Lbx1 expression pattern in the
dorsal horn of the spinal cord.
Mouse Lbx1 Locus
Delivery of Reporter Constructs to
Embryonic Cells
• Different experimental
models can be used.
– Mouse common but
difficult, expensive.
– Chick easy, inexpensive.
• Our method of choice:
electroporation of chick
embryos.
• Method is relatively new.
In Ovo Electroporation: GFP
ß-actin
Enhancer
GFP
Instruments
Positive Control: ß-Actin GFP Expression Vector
Asymmetric Expression of GFP
In Ovo Electroporation: LacZ
Cytomeglavirus
Enhancer
LacZ
Positive Control: ß-Galactosidase Reporter Gene
Results
Conclusion
• Tissue specific enhancer does not exist within our
search area.
• Can now start searching upstream and downstream.
Acknowledgements
Dr. Michael Gross
Dr. Kevin Ahern
Howard Hughes
Medical Institute
Questions?