CHEM2011 Lecture 3: Antibiotics and DNA Targeting Agents
CHEM2011 Lecture 4 Transcription
Study
synthesis of mRNA carried out by?
DNA-dependent RNA polymerase (RNAP)
housekeeping genes
must be expressed at all times because they code for proteins that are necessary for
basic cellular functions
promoters
regions of DNA that signal RNAP to bind to unwind DNA and begin transcription
mediator proteins
interacts with protein at promoter site to bring RNAP closer to the enhancer sequence
and form nucleoprotein assembly
enhancers
short sequences of DNA that increase the rate of transcription
most highly regulated part of transcription?
initiation
initiation followed by
elongation
elongation followed by
termination
sigma factors
determine promoter specificity of RNAP in prokaryotes, each sigma number (e.g.
sigma70) controls specific type of gene
process of RNA transcription
initiating nucleotide triphosphate is bound to unwound DNA, RNAP catalyses first
phosphodiester bond, then translocated to next position and continues adding NTPs
until it switches to elongation mode until it encounters termination signal
RNAP backtracking
removes mis-incorporated or damaged NTPs by hydrolysing bonds
trapped RNAP
can get trapped in backtracking state by stable complex needs to be "bumped" out by
MFD
MFD
searches along DNA for any trapped RNAPs and frees them
operon
group of genes operating together controlled by a single promoter - RNAP transcribes
all genes in the operon
two termination mechanisms in bacteria
rho-independent (intrinsic), rho-dependent
intrinsic termination
mediated by stem-loop structures formed by DNA transcript which promotes RNAP
release from DNA
rho-dependent termination
CHEM2011 Lecture 4 Transcription
Study
synthesis of mRNA carried out by?
DNA-dependent RNA polymerase (RNAP)
housekeeping genes
must be expressed at all times because they code for proteins that are necessary for
basic cellular functions
promoters
regions of DNA that signal RNAP to bind to unwind DNA and begin transcription
mediator proteins
interacts with protein at promoter site to bring RNAP closer to the enhancer sequence
and form nucleoprotein assembly
enhancers
short sequences of DNA that increase the rate of transcription
most highly regulated part of transcription?
initiation
initiation followed by
elongation
elongation followed by
termination
sigma factors
determine promoter specificity of RNAP in prokaryotes, each sigma number (e.g.
sigma70) controls specific type of gene
process of RNA transcription
initiating nucleotide triphosphate is bound to unwound DNA, RNAP catalyses first
phosphodiester bond, then translocated to next position and continues adding NTPs
until it switches to elongation mode until it encounters termination signal
RNAP backtracking
removes mis-incorporated or damaged NTPs by hydrolysing bonds
trapped RNAP
can get trapped in backtracking state by stable complex needs to be "bumped" out by
MFD
MFD
searches along DNA for any trapped RNAPs and frees them
operon
group of genes operating together controlled by a single promoter - RNAP transcribes
all genes in the operon
two termination mechanisms in bacteria
rho-independent (intrinsic), rho-dependent
intrinsic termination
mediated by stem-loop structures formed by DNA transcript which promotes RNAP
release from DNA
rho-dependent termination
