CH 16 Gene Expression

activator

protein that binds to prokaryotic operators to increase transcription

CAP

catabolite activator protein

protein that complexes with cAMP to bind to the promoter sequences of operons which control sugar processing when glucose is not available

DNA methylation

epigenetic modification that leads to gene silencing; a process involving adding a methyl group to the DNA molecule

enhancer

segment of DNA that is upstream, downstream, perhaps thousands of nucleotides away, or on another chromosome that influence the transcription of a specific gene

epigenetic

heritable changes that do not involve changes in the DNA sequence

gene expression

processes that control the turning on or turning off of a gene

histone acetylation

epigenetic modification that leads to gene expression; a process involving adding or removing an acetyl functional group

inducer

a small molecule that either activates or represses transcription

inducible operon

operon that can be activated or repressed depending on cellular needs and the surrounding environment

lac operon

operon in prokaryotic cells that encodes genes required for processing and intake of lactose

microRNA (miRNA)

small RNA molecules that bind to RNA molecules to degrade them

negative regulator

protein that prevents transcription

operator

region of DNA outside of the promoter region that binds activators or repressors that control gene expression in prokaryotic cells

operon

collection of genes involved in a pathway that are transcribed together as a single mRNA in prokaryotic cells

poly-A tail

a series of adenine nucleotides that are attached to the 3' end of an mRNA to protect the end from degradation

positive regulator

protein that increases transcription

post-transcriptional

control of gene expression after the RNA molecule has been created but before it is translated into protein

post-translational

control of gene expression after a protein has been created

repressor

protein that binds to the operator of prokaryotic genes to prevent transcription

transcription factor

protein that binds to the DNA at the promoter or enhancer region and that influences transcription of a gene

transcription factor binding site

sequence of DNA to which a transcription factor binds

trp operon

series of genes necessary to synthesize tryptophan in prokaryotic cells

tryptophan

amino acid that can be synthesized by prokaryotic cells when necessary