Transcript lab - Kodomo

Expansion of tandem gene clusters
Gene duplication by unequal
crossing-over
Divergence of coding and regulatory sequences
Evolution of HOX clusters
The homeobox is a highly conserved DNA-binding domain
HOX4 homeodomain
Drosophila
Amphioxus
Mouse
Human
Chick
Frog
Fugu
Zebrafish
Evolution of HOX clusters in vertebrates
- Vertebrates have multiple
HOX clusters
- Paralogous HOX genes may
Mouse
Fugu
have partly
redundant functions
- Some genes and clusters
become specialized
for distinct functions
- Different lineages lose some
genes and acquire new
functions for others
Zebrafish
Using gene replacement to test HOX gene function
Using gene replacement to test HOX gene function
Functionally equivalent HOX paralogs
HOX gene labial required for tritocerebral commissure
Genetic rescue strategy
lab-Gal4
lab-; lab-Gal4 / UAS - lab
red = HRP; green = Lab
Other HOX genes can partially substitute for lab
Other HOX genes can partially substitute for lab
Distinct roles of Ubx and abd-A in the midgut
dpp expression in the fly
midgut is activated by Ubx,
but repressed by abd-A
Activation and repression are mediated by the same binding
sites within a dpp enhancer
Onychophoran Ubx causes homeotic transformations in Drosophila
Onychophoran Ubx can regulate some Drosophila target genes
dSRF
dpp
Onychophoran Ubx cannot fully substitute for Drosophila Ubx
Chimeric Ubx proteins
Mapping the functional specificity of Onychophoran Ubx
Functional specificity of Ubx maps outside the homeodomain
Conservation and change in Ubx proteins
Mapping the functional specificity of Ubx proteins
Functional comparison of Drosophila and Artemia Ubx
Evolution of a new repression domain
Non-HOX functions of derived HOX genes
Maternal gradient of bicoid establishes AnteriorPosterior axis in the Drosophila embryo
bicoid gradient formation in Drosophila
zen functions in Dorso-Ventral patterning
sna
sog
zen
zen is a derived HOX gene
HOX-like expression of zen homologue in Cupiennius
Evolution of zen and bcd from an ancestral HOX gene
Genetic control of segmentation in Drosophila
ftz deletion does not affect segmentation in Tribolium
Antennae
HOX-like expression of the Chelicerate ftz homologue
Archegozetes longisetosus
Effects of ectopic ftz expression in Drosophila
Dm
36%
4%
Sg
en expression
A homeodomain-deficient ftz allele
ftz expression in Schistocerca
Homeotic antenna to leg transformations
Dm-ftz
Tc-ftz
Tc-ftz
Sg-ftz
Dll-Gal4
Tribolium ftz retains homeotic potential
wt
Dm-ftz
Tc-ftz
Dm-Scr
wt
Dm-ftz
Tc-ftz
Dm-Antp
Evolution of ftz function
Comparison of ftz proteins between Drosophila and Schistocerca
Expression and function of ftz-F1
ftz-F1
ftz
ftz-F1 mutant
en
ftz-F1 encodes a nuclear hormone receptor
Physical interaction between ftz and ftz-F1
Transcriptional activation by ftz / ftz-F1 complex
In yeast
In Drosophila embryos
Novel functions of divergent HOX genes
Loss and gain of protein-protein interaction motifs