Control of Gene Expression in Eukaryotes Flashcards
Differential Gene Expression
Responsible for forming specialized cells types, arranging the into tissues, and coordinating their activity in the multicellular society that is the individual.
Chromatin
DNA wrapped around proteins.
Has profound implications for the control of gene expression.
Must be condensed to expose the promoter so RNA polymerase can bind to it.
Chromatin Remodeling
Process by which the structure of chromatin is changed to allow or inhibit transcription or replication.
RNA Processing
Steps required to produce a mature, processed mRNA from a primary RNA transcript.
Histones
DNA associated proteins.
H1 “seals” DNA to each nucleosome; interact with one another to create tightly packed structures.
Positively charged.
Nucleosome
A bead-like unit of eukaryotic chromatin.
DNases
Enzymes that cut DNA.
Histone Code
Particular combinations of histone modification set the stat of chromatin condensation for a particular gene.
Histone Acetyltansferases (HAT)
ADD acetyl groups to the positively charged lysin residues in histones.
Creates a binding site for other proteins that help open chromatin.
On switch
Histone Deacetylases (HDAC)
REMOVE acetyl groups from histones and lead to condensed chromatin.
Off switch
Chromatin-Remodeling Complexes
Group of proteins that use energy from ATP hydrolysis to shift nucleosomes on DNA.
Epigenetic Inheritance
Any mechanism of inheritance that is due to something other than differences in DNA sequences.
Regulatory Sequences
Serve as a binding site for other proteins needed to start transcription.
Core Promoter
Used to indicate the specific sequence where RNA polymerase bind.
TATA-Binding Protein (TBP)
A protein the binds to the TATA box in eukaryotic promoters and is a component of the basal transcription complex.
TATA Box is a core promoter.
Promoter-Proximal Elements
Have sequences that are unique to specific sets of genes.
Positive control
Introns
Transcribed sequences that are spliced our of the primary transcript.
Exons
Transcribed regions that are included in the mature RNA on splicing is complete.
Enhancers
Regulatory sequences that are far from the promoter and activate transcription.
Many types, most genes have more than one, have different binding sites.
Activators
Bind to enhancers and begin transcription.
Bring chromatin-remodeling proteins to the right place at the right time.
Silencers
Work to inhibit transcription.
Repressors
Bind to silencers and shut down transcription.
Regulatory Transcription Factors
Protein that binds to a DNA regulatory sequence to influence transcription. (Regulatory and general factors)
*Different types of cells express different genes because they have different factors.
Affinity
The strength of a protein’s binding to a target.
General Transcription Factors
Proteins that interact with the core promoter and are not restricted to particular genes or cell types.
i.e. TATA-binding protein
Mediator
Acts as a bridge between regulatory transcription factors, general transcription factors and RNA polymerase II.
Transcriptional Activators
Bind to regulatory sequences of particular genes to recruit proteins needed to remodel chromatin.
Alternative Splicing
Splicing the same primary RNA transcript in different ways.
Controlled by proteins that bind to RNA’s in the nucleus and interact with spliceosomes.
In control of gene expression in multicellular eukaryotes.
Gene
nucleotide sequence that allows the production of one or more related RNAs or polypeptides.
RNA Interference (RNAi)
Occurs when a small, single-stranded RNA held by a protein complex binds to a complementary sequence in mRNA.
Either leads to destruction of the mRNA or blocks the mRNA translation.
Proteasome
Recognizes proteins that have a ubiquitin tag and cuts the into short segments.
DNA Packaging
Decondensed for general and regulatory transcription factors to gain access to genes and fro RNA polymerase to initiate transcription.
