A structure consisting of GTP and methylated sugars that is added to the 5′ ends of eukaryotic mRNAs.
alternative splicing
The generation of different mRNAs by varying the pattern of pre-mRNA splicing.
barrier element
See insulator.
chromatin immunoprecipitation
A method for determining regions of DNA that bind transcription factors within a cell.
chromatin remodeling factor
A protein that disrupts chromatin structure by altering the contacts between DNA and histones.
cis-acting control element
A regulatory DNA sequence that serves as a protein binding site and controls the transcription of adjacent genes.
coactivator
A protein that interacts with a transcription factor to stimulate transcription.
corepressor
A protein that associates with repressors to inhibit gene expression, often by modifying chromatin structure.
footprinting
A method used to identify the sites at which proteins bind to DNA.
DNA-affinity chromatography
A method used to isolate DNA-binding proteins based on their binding to specific DNA sequences.
electrophoretic-mobility shift assay
An assay for the binding of a protein to a specific DNA sequence.
elongation factor
A protein involved in the elongation phase of transcription or translation.
enhancer
A transcriptional regulatory sequence that can be located at a site distant from the promoter.
epigenetic inheritance
The transmission of information that is not contained within the sequence of DNA.
general transcription factor
A transcription factor that is part of the general transcription machinery.
genomic imprinting
The regulation of genes whose expression depends on whether they are maternally or paternally inherited, controlled by DNA methylation.
helix-loop-helix
A transcription factor DNA-binding domain formed by the dimerization of two polypeptide chains. The dimerization domains of these proteins consist of two helical regions separated by a loop.
helix-turn-helix
A transcription factor DNA-binding domain in which three or four helical regions contact DNA.
histone acetylation
The modification of histones by the addition of acetyl groups to specific lysine residues.
HMG protein
Member of a family of nonhistone chromosomal proteins that affect the architecture of chromatin.
homeodomain
A type of DNA binding domain found in transcription factors that regulate gene expression during embryonic development.
insulator
A sequence that divides chromatin into independent domains and prevents an enhancer from acting on a promoter in a separate domain.
leucine zipper
A protein dimerization domain containing repeated leucine residues; found in many transcription factors.
Mediator
A complex of proteins that stimulates transcription of eukaryotic protein-coding genes and allows them to respond to gene-specific regulatory factors.
nonsense-mediated mRNA decay
Degradation of mRNAs that lack complete open-reading frames.
operator
A regulatory sequence of DNA that controls transcription of an operon.
operon
A group of adjacent genes transcribed as a single mRNA.
poly-A tail
A tract of about 200 adenine nucleotides added to the 3′ ends of eukaryotic mRNAs.
polyadenylation
The process of adding a poly-A tail to a pre-mRNA.
pre-mRNA
The primary transcript, which is processed to form messenger RNA in eukaryotic cells.
pre-rRNA
The primary transcript, which is cleaved to form individual ribosomal RNAs (the 28S, 18S, and 5.8S rRNAs of higher eukaryotic cells).
pre-tRNA
The primary transcript, which is cleaved to form transfer RNAs.
promoter
A DNA sequence at which RNA polymerase binds to initiate transcription.
repressor
A regulatory molecule that blocks transcription.
ribozyme
An RNA enzyme.
RNA editing
RNA processing events other than splicing that alter the protein coding sequences of mRNAs.
RNA polymerase
An enzyme that catalyzes the synthesis of RNA.
RNase P
A ribozyme that cleaves the 5′ end of pre-tRNAs.
self-splicing
The ability of some RNAs to catalyze the removal of their own introns.
small nuclear ribonucleoprotein particle (snRNP)
Complex of an snRNA with proteins.
small nuclear RNA (snRNA)
A nuclear RNA ranging in size from 50 to 200 bases.
spliceosome
A large complex of snRNAs and proteins that catalyzes the splicing of pre-mRNAs.
steroid hormone receptor
A transcription factor that regulates gene expression in response to steroid hormones.
TATA box
A regulatory DNA sequence found in the promoters of many eukaryotic genes transcribed by RNA polymerase II.
TATA-binding protein (TBP)
A basal transcription factor that binds directly to the TATA box.
TBP-associated factor (TAF)
A polypeptide associated with TBP in the general transcription factor TFIID.
trans-acting factor
A transcriptional regulatory protein.
transcription factor
A protein that regulates the activity of RNA polymerase.
transcriptional activator
A transcription factor that stimulates transcription.
X-chromosome inactivation
A dosage compensation mechanism in which most of the genes on one X chromosome are inactivated in female cells.
zinc finger domain
A type of DNA binding domain consisting of loops containing cysteine and histidine residues that bind zinc ions.
