Gene Regulation and Expression

Flashcards covering key terms and concepts from gene regulation and expression.

Gene Regulation

The process by which cells control gene expression, determining when, where, and how much of a gene is expressed.

Differential Gene Expression

The process through which cells with the same genome become different cell types by expressing different sets of genes.

Temporal Regulation

Control of when genes are expressed during development.

Spatial Regulation

Control of where genes are expressed in an organism.

Multicellular Organisms

Organisms composed of multiple cells that can differentiate into various cell types.

Cell Specialization

The process by which generic cells undergo changes to form specialized cells.

Environmental Signals

External cues, such as hormones or nutrients, that influence gene expression.

Transcriptional Control

Regulation of gene expression at the transcription stage, involving activators, repressors, and promoter strength.

Post-transcriptional Control

Regulation occurring after transcription, affecting mRNA stability and RNA processing.

Translational Control

Regulation of gene expression at the level of translation, often involving ribosome binding.

Post-translational Control

Regulation that occurs after protein synthesis, including protein folding, modification, and degradation.

Nucleosome

The fundamental unit of chromatin, consisting of DNA wrapped around histone proteins.

Histone Octamer

A core of eight histone proteins around which DNA is wrapped in a nucleosome.

Histone Acetylation

A histone modification that increases gene expression by adding acetyl groups to histones.

Histone Deacetylases (HDACs)

Enzymes that remove acetyl groups from histones, leading to decreased gene expression.

Histone Methylation

The addition of methyl groups to histones, which can repress or activate gene expression, depending on the context.

Histone Methyltransferases (HMTs)

Enzymes that add methyl groups to histones.

Histone Demethylases (HDMs)

Enzymes that remove methyl groups from histones.

Chromatin Structure Regulation

Modifications that affect packaging of DNA into chromatin, influencing gene accessibility.

DNA Methylation

The addition of methyl groups to DNA, typically leading to gene silencing.

CpG Dinucleotides

DNA sequences where a cytosine is followed by a guanine, often methylated at cytosines.

Genomic Imprinting

An epigenetic phenomenon whereby only one allele of a gene is expressed depending on its parental origin.

siRNA

Short interfering RNA that plays a role in gene regulation by targeting mRNA for cleavage.

miRNA

MicroRNA that regulates gene expression by binding to mRNA and inhibiting translation.

Activators

Proteins that enhance gene transcription by binding to enhancer regions.

Repressors

Proteins that decrease gene transcription by binding to silencer regions or blocking activators.

Coactivator

A protein that assists activators in stimulating transcription without binding DNA itself.

Inducible Genes

Genes that are expressed only in response to specific signals.

Repressible Genes

Genes that are turned off when a specific molecule is present.

Constitutive Genes

Genes that are continuously expressed regardless of external conditions.

Promoter

A DNA sequence where RNA polymerase binds to initiate transcription.

Core Promoter

The minimal DNA element necessary for basal transcription, including the TATA box.

Enhancer

A regulatory DNA sequence that increases transcription when bound by activators.

Silencer

A regulatory DNA sequence that repressors bind to in order to decrease transcription.

Transcription Factor

A protein that binds to DNA and regulates the transcription of genes.

Mediator Complex

A large coactivator complex that links activators to RNA polymerase II.

Histone

Proteins that help package DNA into nucleosomes and can undergo various modifications.

CpG Island

Regions rich in CpG dinucleotides, typically located near active promoters.

Epigenetics

Heritable changes in gene expression not caused by changes in DNA sequence.

Alternative Splicing

A process that allows a single gene to produce multiple mRNA isoforms.

RNA Interference (RNAi)

A biological process where RNA molecules inhibit gene expression or translation.

Drosha

An enzyme that processes primary miRNA into pre-miRNA in the nucleus.

Dicer

An enzyme that cuts precursor RNA into siRNA or miRNA.

Argonaute

Core protein of the RNA-induced silencing complex (RISC) that mediates RNA interference.

RISC

RNA-Induced Silencing Complex that uses RNA to target mRNAs for inhibition.

Reporter Construct

A genetic construct used to study the activity of regulatory sequences.

Reporter Gene

A gene used to measure the activity of regulatory sequences, commonly GFP, luciferase, or LacZ.

Antisense RNA

RNA that is complementary to a specific mRNA and can block its translation.

Transcriptome

The complete set of RNA transcripts produced by the genome at a specific time.

Transcription Machinery

The complex of proteins and molecules that execute the transcription of DNA into RNA.

Gene Activation

The process by which a gene is turned on to produce its corresponding RNA or protein.

Gene Silencing

The process of downregulating or completely shutting off the expression of a gene.

Chromatin Relaxation

The process by which chromatin structure loosens, increasing accessibility for transcription.

Chromatin Compaction

The tightening or folding of chromatin that decreases gene accessibility for transcription.

Transcription Initiation

The first step of transcription where RNA polymerase binds to the promoter and begins synthesizing RNA.

Mutational Impact on Expression

Changes in gene expression levels resulting from mutations in regulatory regions or coding sequences.

Regulatory DNA Sequence

DNA elements such as enhancers or silencers that influence gene transcription.

Epigenetic Marks

Chemical modifications on DNA or histones that regulate gene expression without altering the DNA sequence.

Acetylation of Histones

The addition of acetyl groups to histones, typically associated with increased gene expression.

Transcriptional Activators

Proteins that promote the interaction between RNA polymerase and the promoter, enhancing transcription.

HATs

Histone Acetyltransferases, enzymes that add acetyl groups to histones.

RNA Binding Sites

Specific sequences on mRNA that ribosomes and regulatory proteins recognize for translation.

Basal Transcription

The minimal level of transcription required for any gene to be expressed.

Gene Regulation Mechanism

The various processes and interactions that determine gene expression levels in cells.

Facilitated Transcription

Enhancing the process of transcription through structural changes in chromatin.

5' Cap Modification

Addition of a cap to the 5' end of mRNA that enhances stability and translation efficiency.

3' Poly-A Tail

A series of adenine nucleotides added to the 3' end of mRNA that aids in nuclear export and stability.

RNA Stability

The lifespan of mRNA in the cell, affecting how long it can be translated.

Pre-initiation Complex

A multiprotein complex that assembles at promoters before transcription begins.

Long-range Control of Gene Expression

Regulation of genes that operates over large genomic distances, often impacting multiple genes.

Integrative Gene Regulation

A coordinated approach to regulating gene expression based on various signals.

Nuclear Envelope

The double membrane surrounding the nucleus, separating it from the cytoplasm.

Gene Activation Signals

Molecular signals that promote the activation of gene transcription.

Cell Cycle Regulation

Mechanisms that control the progression of cells through the cycle of cell division.

Cell Differentiation

The process by which unspecialized cells develop into specialized cell types.

Organ Formation

The process by which groups of specialized cells develop into whole tissues and organs.

Protein Modifications

Chemical changes to proteins that can alter their function, stability, or localization.