Hox genes Flashcards
(20 cards)
What do Hox genes encode?
Transcription factors with a homeodomain
How are Hox genes organised?
In clusters (A-D) with spatial and temporal collinearity
What is spatial collinearity?
Genes at 3’ end expressed anteriorly; 5’ end expressed posteriorly
What is temporal collinearity?
Genes expressed in order along the body over time
What do Hox genes do in development?
Provide positional identity along A-P acis
How are Hox genes regulated?
By morphogens: RA (anterior), FGF/Wnt (posterior
Which Hox genes pattern the stylopod?
Hox9
Which Hox genes pattern the zeugopod?
Hox10-11
Which Hox genes pattern the autopod?
Hox12-13
What happens if Hox genes are knocked out?
Homeotic transformations or limb truncations
Which pathway maintains distal HoxD expression?
SHH from ZPA
Which Hox gene is linked to digit patterning
HoxD13
What can HoxD13 misexpression cause?
Synpolydactyly
What establishes the limb field A-P identity?
Overlapping Hox gene domains
Where are Hox genes expressed during somitogenesis?
In presomitic mesoderm and somites
What is the role of retinoic acid in Hox expression?
Promotes anterior Hox expression
What defines vertebral identity?
Hox gene expression profile in somites
What is a homeotic transformation?
One body part developing like another due to Hox misexpression
Are Hox genes conserved across species?
Yes, Hox genes are highly conserved in vertebrates
How many Hox clusters do humans have?
Four: A, B, C and D
