TRANSCRIPTION REGULATION & DEVELOPMENT

Exam 2

How is expression of the Eve gene regulated in Drosophila?

By a series of regulatory segments which directs the production of Eve stripes along the embryo.

• Contains 2 repressors (Giant and Kruppel)

• Contains 2 activators (Bicoid and Hunchback)

  • Giant, Bicoid and Hunchback present in anterior

  • Hunchback and Bicoid (slightly) present in middle (where Eve stripe 2 forms)

  • Kruppel and Bicoid (slightly) present in posterior

What role does the Eve gene play in Drosophila embryonic development?

The single-celled embryo needed to be further divided into segments for continued development of the fly (will become parts of the head, thorax, abdomen, etc.)

What role do maternal mRNAs, gap genes, and pair-rule genes play in Drosophila embryonic development?

BOTH EMBRYONIC GENES

• Gap genes: Establish the segmented body plan of the embryo along the anterior-posterior axis (head-butt)

• Pair-rule genes: Expressed genes as a result of differing concentrations of maternal proteins and/or gap genes, which further divides the embryo into banded segments (the body segments). Can be regulated by gap genes

What are Hox genes and Hox proteins?

• Hox genes encode proteins that are transcription regulators

• Hox proteins are critical components of animal development. They direct the development of particular body segments and specify the position of structures within the segments

How do Hox genes/proteins work?

They regulate gene expression by determining which segments should be developed and where, by binding to the DNA sequence

What role do Hox genes/proteins play in the evolution of diverse body plans in the animal tree of life?

Mutations in Hox genes can lead to shifts in development and changes in morphology and body parts, which is critical to evolution because Hox genes are conserved across animals