Gene expression Flashcards
recognize specific sequences of DNA (cis-regulatory sequences)
Transcription regulators
lie near the gene; intergenic region directly upstream from the transcription start point of the gene
Cis-regulatory sequences
A very long double helix has both ___ and ___ groove
Major and Minor
recognizes a specific cis regulatory sequence because the surface of the protein is extensively complementary to the special surface features of the double helix that displays that sequence.
A transcription regulator
promotes cooperative binding of transcription regulators
Nucleosome structure
Regulation of glucose metabolism
Glucocorticoid
active form → switches genes OFF or represses them
Transcriptional repressor
proteins (work on promoters ) → switch genes ON or activate them
Transcriptional activator
Lac operon is controlled
Lac repressor
CAP activator
allow a protein bound at a distant site along the DNA to contact RNA polymerase
DNA looping
positive transcription regulators
Activators
negative transcription regulators
Repressors
the whole expanse of DNA involved in regulating and initiating transcription of a eukaryotic gene
gene control region
sequences that transcription regulators do not directly recognize; lncRNAs
“spacer” DNA
often formed from two diferent transcription regulators.
Heterodimers
over a range of concentrations of the transcription regulator, binding is more of an all-or-none phenomenon
Cooperative binding
a cluster on the chromosome and are transcribed from a single promoter as one long mRNA molecule; such coordinately transcribed clusters are called
operons
When tryptophan conc. are low, the operon is
Transcribes
work on promoters that in contrast to the promoter for the tryptophan operon—are only marginally able to bind and position RNA polymerase on their own
Transcriptional activator proteins
One of the most prevalent coactivators is the large
composed of more than 30 subunites
Mediator protein complex
exhibit by transcription activators
several DNA-bound activator proteins working together produce a transcription rate that is much higher than the sum of their transcription rates working alone
Transcriptional synergy
A second type of DNA element
prevents cis-regulatory sequences from running amok and activating inappropriate genes
Insulator
is a prerequisite for the creation of organized tissues and for the maintenance of stably diferentiated cell types.
Cell memory
through which cells integrate signals and remember events in their past.
logic circuits
whose expression plays an important part in the development of the Drosophila embryo.
Drosophila Even-skipped (eve) gene
distinguishes one part of the embryo from another
positional information
