L8 Flashcards
homeotic transformation/homeosis?
one body part is transformed into another
embryonic cuticles have ______ that are uniquely structured in each segment
denticle belts
what do denticle belts do?
allow identification of each segments anterior / posterior identity
all homeotic genes are homeobox genes true or false
false
HX gene is involved in interacting with ____ to add _____
cofactor
specificity
____ hox proteins bind the same short ____ sequence with ___ affinity
different
DNA
high
gap genes do what
divide embryo to even more smaller and discrete regions
initial activation of hox genes are remembered by what
chromatin
polycomb group describe
repressive
modify histones to keep it closed and inaccessible
trithorax group describe
opening up chromatin - keeps regions active
polytene chromosomes are where in drosophila?
salivary glands
what is the effect of LOF mutations in hox genes?
when you lose function in HOX gene, the identity of all the segments in the region where the HOX gene is expressed acquire that an anterior identity of the next most anterior sequence
what is the effect of GOF mutation in HOX gene?
gene itself is the same and does the same thing but is just expressed somewhere additional it shouldn’t be
what is posterior prevelance
when phenotypically, the most posteriorly expressed hox genes win
how do you study GOF mutations
use heat shock promoter to express ubx gene throughout axis
homeotic mutations identify ____
homeotic genes
the hexapeptide motif is often diagnostic for _____ identity
hox gene
the homeodomain of all Hox genes is highly _____ both within and between animals
conserved
initial domains of homeotic gene expression are influenced by ________ and ______ genes
gap
pair-rule
polycomb proteins lock-in what and how?
stable expression patterns
by forming inactive chromatin structures
trithroax proteins bind ___ and alter ____ structure to give _____
DNA
chromatin
transcription
_____ expression domains in anterior
discrete
_____ expression domains in posterior
nested
hox gene function establishes the _____ of segments
identity
a GOF Antp mutation in the antennal segment converts the appendage into a _____
leg
