Alberts, Ch 7 - Control of Gene Expression Flashcards
Cell memory
Retention by cells and their descendants of persistently altered patterns of gene expression, without any change in DNA sequence
CG island
Region of DNA in vertebrate genomes with a greater than averagedensity of CG sequences, remains generally unmethylated
Cis-regulatory sequence
DNA sequences to which transcription regulators bind to control the rte of gene transcription, in nearly all case these sequences must be on the same chromosome to the genes they control
CRISPR
A defense mechanism in bactria using small noncoding RNA molecules (crRNAs) to seek out and destroy invading viral genomes through complementary base-pairing and targeted nuclease digestion
Alternative RNA splicing
Production of different RNAs from the same gene by splicing the transcript in different ways
crRNA
Small noncoding RNAs that are effectors of DRISPR-mediated immunity in bacteria
DNA methylation
Addition of methyl groups to DNA, extensive methlation of cytosine in CG sequences is used in plants and animals to help keep genes in an inactive state
Epigenetic inheritance
Inheritance of phenotypic changes in a cell or organism that do not result from changes in the nucleotide sequence of DNA, can be due to positive feedback loops of transcription regulators or to heritable modifications in chromatin such as DNA methylation or histone modifications
Gene
Region of DNA that is transcribed as a single unit and carries information for a discrete hereditary characteristic, usually corresponding to a single protein or a single RNA (or set of closely related protein/RNA)
Gene control region
The set of linked DNA sequences regulating expression of a particular gene, includes promoter and cis-regulatory sequences required to initiate transcription of the gene and control the rate of transcription
Genomic imprinting
Phenomenon in which a gene is either expressed or not expressed in the offspring depending on which parent it is inerited from
Induced pluripotent stem cells (iPS cells)
Cells that are induced by artificial expression of specific transcription regulators to look and behave like the pluripotent embryonic stem cells that are derived from embryos
Internal ribosome entry site (IRES)
Specific site in a eukaryotic mRNA, other than at the 5’ end at which translation can be initiated
Long noncoding RNA (lncRNA)
One of a large group of RNAs longer than 200 nucleotides long not coding for protein, functions of most lncRNAs is unknown but individual lncRNA are known to play important roles in the cell like in telomerase function and in genomic imprinting, in general sense are believed to act as scaffolds, holding together proteins and nucleic acids to speed up a wide variety of reactions in the cell
Master transcription regulator
A transcription regulator specifically required for formation of a particular cell type, artificial expression will often convert one cell type into another
microRNA (miRNA)
Short RNA, produced by the processing of specialized RNA transcripts coded in the genome, that regulate gene expression through base-pairing with mRNA
Monoallelic gene expression
Expression of only one of the two copies of a gene in a diploid genome, occuring for example as a result if imprinting of X-chromosome inactivation
mRNA degradation control
Regulation by a cell of gene expression by selectively preserving or destroying certain mRNAs in the cytoplasm
Piwi-interacting RNA (piRNA)
A class of small noncoding RNAs made in the germ line that in complex with Piwi proteins keep in check the movement of transposable elements by transcriptionally silencing transposon genes and destroying RNAs produced by them
Post-transcriptional controls
Any control on gene expression that is exerted at a stage after transcriptionhas begun
Promoter
Nucleotide sequence in DNA to which RNA polymerase binds to begin transcription
Protein activity control
The selective activation, inactivation, degradation or compartmentalization of specific proteins after they have been made, one of the means by which a cell controls which proteins are active at a given time or location in the cell
Regulated nuclear transport
Mechanisms controlling export of mRNAs from the nucleus to the cytosol that can be used to regulate gene expression, also includes the selective import of proteins and RNA molecules into the nucleus
RNA editing
Type of RNA processinf that alters the nucleotide sequence of an RNA transcript after it is synthesized by inserting, deleting or altering individual nucleotides
RNA interference (RNAi)
Mechanism by which an experimentally introduces double-stranded RNA induces sequences-specific destruction of complementary mRNAs, often used to include the inhibition og gene expression by miRNAs and piRNAs which are encoded in the cell’s own genome
RNA processing control
Regulation by a cell of gene expression by controlling the processing of RNA transcripts which includes splicing
RNA transport and localization control
Regulation by a cell of gene expression by selecting which completed mRNAs are exported from the nucleus to the cytosol and determining where in the cytosol they are localized
Small interfering RNA (siRNA)
Short double-stranded RNAs that inhibit gene expression by directing destruction of complementary mRNAs, production is usually triggered by exogenously introduced double-stranded RNA
Transcription regulators
General name for any protein that binds to a specific DNA sequence to influence the transcription of a gene
Transcriptional control
Regulation by a cell of gene expression by controlling when and how often a given gene is transcribed
Translational control
Reulation by a cell of gene expressionby selecting which mRNAs in the cytoplasm are translated by ribosomes
X-inactivation
Inactivation of one copy of the X chromosome in somatic cells of female mammals
X-inactivation center (XIC)
Site in an X chromosome at which inactivation is initiated and spreads outward
