Solutions For An Introduction to Genetic Analysis Chapter 12 Problem 11P

The similar analogies between prokaryotic and eukaryotic Trans-acting elements are as follows:

• Have similar binding locations on DNA

• Have high specificity towards the ligand and binding location on the DNA

• Share structural homology

They have similar binding locations on DNA or a gene for both prokaryotes and eukaryotes. Most of the Trans-acting proteins bind on the upstream sequences like TATA box, CAT box and GC box sequences. For example, the major regulator of Galactose operon is GAL4 gene, which expresses a protein called GAL4-protein. This protein specifically binds on some Upstream-activating-sequences (UAS) elements that are present prior to +1 region of the structural genes. Binding of GAL4-protein to UAS elements result expression of structural genes, therefore GAL4-protein is called the transcriptional activator protein.

Both eukaryotic and prokaryotic Trans-acting proteins have high specificity. For example, nuclear estrogen receptors, namely ERα and ERβ which are encoded by the ESR1 and ESR2 genes binds on specifically on the upstream sequence of ovalbumin gene.

Both eukaryotic and prokaryotic Trans-acting proteins share structural homology with respect to their DNA binding domains or ligand binding domains.