Control Of Gene Expression Flashcards
Regulatory Gene
DNA sequence that encodes a protein or RNA molecule that interacts with other DNA sequences and affects transcription or translation of those sequences.
Structural Gene
DNA sequence that encodes a protein that functions in metabolism or biosynthesis or that has a structural role in the cell.
Regulatory Element
DNA sequence that affects the transcription of other DNA sequences to which it is physically linked.
Gene Regulation
Mechanisms and systems that control the expression of genes.
Constitutive Gene
A gene that is expressed continually without regulation.
Levels Of Gene Regulation
Epigenetic, transcriptional, post-transcriptional, translational, and post-translational.
Regulator Protein
Protein produced by a regulator gene that binds to another DNA sequence and controls the transcription of other genes.
Operon
A group of bacterial structural genes that are transcribed together, along with their promoter and additional sequences that control their transcription.
Regulator Gene
Gene associated with an operon in bacterial cells that encodes a protein or RNA molecule that functions in controlling the transcription of other genes.
Operator
DNA sequence in an operon to which a regulator protein binds; this binding affects the rate of transcription of the structural genes.
Positive Control
Transcriptional control in which a regulatory protein is an activator, stimulating transcription.
Negative Control
Transcriptional control in which a regulatory protein is a repressor, binding to DNA and inhibiting transcription.
Inducible Operon
Operon in which transcription is normally off (not taking place); something must happen to induce transcription, or turn it on.
Inducer
Substance that stimulates transcription in an inducible system of gene regulation; usually a small molecule that binds to a repressor protein and alters that repressor so that it can no longer bind to DNA and inhibit transcription.
Repressible Operon
Operon in which transcription is normally on (taking place); something must happen to repress transcription, or turn it off.
Corepressor
Substance that inhibits transcription in a repressible system of gene regulation; usually a small molecule that binds to a repressor protein and alters it so that the repressor is able to bind to DNA and inhibit transcription.
Catabolite Activator Protein (CAP)
Protein that functions in catabolite repression. When bound with cAMP, it binds to the promoters of certain operons and stimulates transcription.
RNA Interference
Process in which cleavage of double-stranded RNA produces small RNAs (siRNAs or miRNAs) that bind to mRNAs containing complementary sequences and bring about their cleavage and degradation thereby silencing expression.
cAMP
Modified nucleotide that functions in catabolite repression. Low levels of glucose stimulate high levels of it; it then attaches to CAP, which binds to the promoters of certain operons and stimulates transcription.
Chromatin Remodeling Complex
Complex of proteins that bind directly to particular sites on DNA and reposition the nucleosomes, allowing other transcription factors and RNA polymerase to bind to promoters and initiate transcription.
Histone Code
Modifications of histone proteins, such as the addition or removal of phosphate groups, methyl groups, or acetyl groups, that encode information affecting how genes are expressed.
Trp Operon
A group of genes that are transcribed together, encoding the enzymes that produce the amino acid tryptophan in bacteria.
Genomic Imprinting
Differential expression of a gene depending on whether it is inherited from the male or female parent.
Lac Operon
A group of genes required for the transport and metabolism of lactose in bacteria like E. coli.
Epigenetics
Phenomena due to alterations in DNA that do not include changes in the base sequence; often affects the way in which DNA sequences are expressed. Such alterations are often stable and heritable in the sense that they are passed to descendant cells or individuals.
DNA Methylation
Modification of DNA by the addition of methyl groups by specific enzymes to certain positions on the bases.
