Question

Consider cross-regulatory interactions of Drosophila gap genes (“+” and “-“ reflect positive and negative interactions. Predict the effect of the following conditions on gene expression domains – specify effect on both anterior and posterior expression boundaries.

hb 100% 90% a0 % 70% 60% 50% 40% 30% 2 % 10%EL

hint: for each gap gene domain, consider anterior and posterior boundary separately

----In the eve-stripe 2 enhancer, predict the effect of mutating the Kr (orange) binding sites

Answer 1

Answers:

i.mutation kr binding sites in eve-stripe 2 result in wild type embryo into stripe normal, it does not expand posteriorly

ii. kr has more than one function in drosophila embryos

iii. negative regulator of eve-stripe 2 sets posterior boundary for expression

iv. hb expands posteriorly in the kr mutants so that the stripe expanded posteriorly because mutated could not expanded posteriorly hb protein