Readiness Reading: Regulating Gene Expression

Gene expression

The entire set of processes that results in using the information stored in a gene.

Positive control (over gene expression)

Mechanisms that increase the amount of active gene product available.

Negative control (over gene expression)

Mechanisms that decrease the amount of active gene product available.

Operon

A sequence of structural gene sequences whose products have related functions and that are under the control of the same promoter and other regulatory sequences, meaning that they are transcribed as a unit.

Transcription factors

Proteins that regulate transcription, often by binding to regulatory sequences in DNA.

Exons

In eukaryotic genes, sections of the coding sequence code for amino acids found in a protein product.

Introns

In eukaryotic genes, sections of the coding sequence that are transcribed but later removed before an mRNA is translated into a protein product.

Chromatin

The complex of DNA and histones that makes up a chromosome.

Nucleosome

A group of four histone proteins that has DNA wrapped around it.

Histone proteins

Proteins that have an abundance of positively charged lysines and arginines in their primary structure, which interact with negative charges on the sugar-phosphate backbone of DNA to form nucleosomes. 

5′ cap

A modified form of the nucleotide guanine (G) that is added to the 5′ end of a pre-mRNA in eukaryotes, during RNA processing that occurs prior to export from the nucleus.

Intron splicing

Removing introns from pre-mRNAs and rejoining exons into a continuous strand, during RNA processing that occurs prior to export from the nucleus.

Poly-A tail

A long series of adenine (A) nucleotides that is added to the 3′ end of a pre-mRNA in eukaryotes, during RNA processing that occurs prior to export from the nucleus.

Protein phosphorylation

The addition of a phosphate group or ATP to a protein.

Kinase

An enzyme that adds a phosphate group to other proteins.