MCB 317 Genetics and Genomics MCB 317 Topic 10, part 3 A Story of Transcription

Why are Acitvators cartooned as two balls held together by a tether? Co-activators & chromatin remodeling complexes not shown

General Factors RNAP Activators Properties of Activators

Activators Multiple functions = multiple domains DNA binding domain Activation domain Dimerization domain (some) Ligand binding domain (some)

Genes in Yeast vs. Larger Euk

Reporter gene in yeast -> use to study activators

Deletion Analysis of Coding Region -> Truncated Proteins

Domains of Activators

Properties of Activators: Transcription factor families

Gene Families It is more common to create variations of a useful protein structure than it is to create a new structure Families created by gene duplication and divergence

Gene Families are Generated by Duplication and Divergence

Activators Multiple functions = multiple domains DNA binding domain Activation domain Dimerization domain (some) Ligand binding domain (some)

Helix-turn-helix Helix-loop-helix Homeobox Zinc finger Leucine zipper Activators classified based on their DNA binding domain: Transcription factor families

Different Family Members = Different Binding Site Protein Domains and Structural Motifs

Protein – DNA interaction General Properties of Proteins that bind DNA

Helix-turn-helix

Homeodomain

Zinc finger type I structure

Leucine Zipper Activators (factors) that dimerize only bind DNA as dimers

Homodimers bind inverted repeats

Homodimers, Heterodimers, Family Members and Recognition Sites

Zinc-finger type II Heterodimers

Helix-loop-helix dimer

Cell Type Specific Patterns of Txn = Combination of Which Receptors and Txn Factors (Activators) a Cell Produces

Some Key Activators -> Txn of other Activators

Activators Multiple functions = multiple domains DNA binding domain Activation domain Dimerization domain (some) Ligand binding domain (some)

Gene family members Gene Ortholog Paralog Orthologs = family members in different species Paralogs = family members in same species

Blast Search Yeast = 34 Zinc Finger Txn Factors (Activators)

Ab Protein Expression Pattern Gene Gene (Organism 2) Paralogs Mutant Gene Biochemistry Genetics Mutant Organism Orthologs and Paralogs 9

Many Types of Steroid Hormones

A Variety of Family Members of Steroid-binding Txn Factors (Activators) In General Family Members have similar properties: Monomer v. dimer, mode of activation/inhibition, even types of genes regulated: homeodomains -> genes invovled in development

Gene Families It is more common to create variations of a useful protein structure than it is to create a new structure Families created by gene duplication and divergence