Chapter 16 - Regulation of gene expression Eukaryotes

Heterochromatin

highly condenced, not expressed

euchromatin

loose, expressed

Structural organization of chromatin

Can be tightly packed or loosly packed, controlled by histones

Epigenetic inheritance

inheritance of traits not directly involving DNA

Histone acetylation

Increases gene expression, makes euchromatin

DNA methylation

decreases gene expression, makes heterochromatin

Enhancer

A group of distal control elements that bind to an activator; Different enhancers code for different genes; also called transciption factors

Activator

proteins that bind to enhancer; allow for the transcription complex to form; not all activators are present in all cells, allowing for cell to specialize depending on what activators they have

Post transciption regulation

The control of gene expression after transciption

ubiquitination

the length of time each protein function is regulated by the selective degradation of ubiquitin; the cell marks protein for degradation by attaching ubiquitin to them, then proteasomes look for ubitquitin and degrade those proteins

noncoding RNA/ ncRNA

Rna that doesnt code for proteins but does contribue to gene expression

microRNA / miRNA

binds to complementary mRNA sequences to inhibit translation and promode degradation

siRNA

binds to mRNA and triggers cleavage and degration

Cell differentiation in embryos

Based on the concentration of bicoid protein, a trasciption factor/enhancer