2. Background
Kim, C. (Artist). (2008). Transcription Factor. Duke University Howard Hughes Undergraduate Programs. Retrieved April 14, 2013, from
http://howardhughes.trinity.duke.edu
3. Arthropod Embryological
Development
âą Engrailed acts as a segment-polarity gene in early
embryological development of Drosophila
âą It defines polarity along the anterior-posterior axis
â Creates 14 parasegments
âą Defines anterior-posterior boundary within each
parasegment
â Engrailed is found in the posterior region of each
parasegment
âą Has a role in brain development
â Defines mid-/hindbrain border
â Guides neuronal axons
4. Segment Polarity Gene
âą Engrailed gene is a segment polarity gene
âą Engrailed Protein
Schmidt, J. W. (Artist). (2004). Fig. 6 Pair rule. Wikimedia Commons.
Retrieved April 14, 2013, from
http://en.wikipedia.org/wiki/Drosophila_embryogenesis#Additional_se
gmentation_genes
Schmidt, J. W. (Artist). (2004). Figure 7.
Reciprocal signaling between Wingless and Hedgehog producing cells.
Wikimedia Commons. Retrieved April 14, 2013, from
http://en.wikipedia.org/wiki/
Drosophila_embryogenesis#Additional_segmentation_genes
5. Anterior-Posterior Axis Patterning in
Drosophila
âą One of the main types of genes involved is
segmentation genes, including engrailed
âą Embryological stripes are the result of 14
segments with engrailed expressed in the
posterior region of each segment
6. Function
âą Brain Development
âą Axon guidance
âą First known for its role in
arthropod embryological
development
(2001-2002). MedEdCenter. Retrieved April 14, 2013,
from http://www.edoctoronline.com
7. Nucleotide Sequence Analysis
Figure 1. Engrailed Gene DNA Sequence Analysis Comparison Among Fly, Norway Rat, Zebrafish, and Western Clawed Frog.
Florence Corpet. (2013). MultiAlin result page. In MultiAlin. Retrieved April 9, 2013, from http://multalin.toulouse.inra.fr/multalin/cgi-bin/multalin.pl
9. Protein Sequence Analysis
Figure 3. Engrailed Geneâs Protein Sequence Analysis Comparison of Fly, House Mouse, Human, Norway Rat, Zebrafish, Western Clawed Frog, Purple
Sea-Urchin, Nematode, and Domestic Chicken.
Florence Corpet. (2013). MultiAlin result page. In MultiAlin. Retrieved April 9, 2013, from http://multalin.toulouse.inra.fr/multalin/cgi-bin/multalin.pl
11. Research
âą Kornberg et al.
examined homozygous
engrailed mutants and
heterozygous (mosaic
cell) mutants
â Homozygous died with
fused, abnormal
segments
â Mosaic cell suffer
abnormalities in the
posterior segments
âą Hidalgo examined
processes regulated by
engrailed during
morphogenesis of the
fly wing
â Found that engrailed has
more than just a
patterning function
transcription factor involved in many aspects of multicellular developmentTranscription factors are proteins involved in the regulation of gene expressionsometimes called a sequence-specific DNA-binding factor) is a protein that binds to specific DNA sequences, thereby controlling the flow (or transcription) of genetic information from DNA to mRNA
Engrailed is a segmentation gene expressed in a series of stripes throughout embryonic development.the segment polarity genes : involved in interactions between the cells of adjacent parasegments---- fundamental unit of drosophila development- made up of proportions of two adj. segments along body of embryoThe Engrailed protein is a transcription factor that is expressed in one row of cells at the edge of each parasegment.
Engrailed gene of Drosophila creates border between hind brain and mid brain⊠guides axons and nuerons where they need to go
RED? = high consensus regions (same across all species)BLUE? = low consensus regions (same among some, but not all, species)Black = neutral (variable between species)Top of picture notes the enzymatic portion of seq⊠w/ higher consensus and bottom of picture = structural part⊠w/ lower consensus??? Talk about diff. between structural and enzymatic???
Fly is the most remote.. 95% consensus between western clawed Frog and zebrafish
Seq. of amino acidsBlue = high consensus regions (same across all species)--- Dr. Toma said the Brown or red here is the high consensus⊠was this right?Brown = low consensus regions (same among some, but not all, species)Black = neutral (variable between species)Diff between structural and enzymatic portion of protein: BLUe part is structural= low consensus and brown = high consensus⊠High consensus = enzymatic portion of protein⊠more accurate than the DNA sequence b/c protein is actually doing a specific job? There are many codons for just one amino acid⊠!
Note the percentages⊠Nematode is the most remote. 82% related to house mouse and humanâŠ. Talk about percentarges.Say! But note ⊠the purple sea urchin and Western clawed frog are not more closely related to human than then the norway rat⊠Therefore canât just look at one protein (Engrailed Protein) from Engrailed Gene to tell us phylogeny.