Genetics summary – VU BMS 2020/2021
Simone Zweers
Reference: Brooker, Genetics: Analysis and prinicples, 7th edition
Chapter 14: Gene regulation in bacteria
1
, Genetics summary – VU BMS 2020/2021
Simone Zweers
Reference: Brooker, Genetics: Analysis and prinicples, 7th edition
- Gene regulation is the phenomenon in which the level of gene
expression can vary under different conditions
- Constitutive genes are unregulated genes always expression
encode proteins that are continuously needed for the survival of
the bacterium
- Common processes regulated at the genetic level:
o Metabolism – some proteins function in the metabolism of
small molecules for example enzymes that are only
required when the sugars are present in the environment of
the bacterium
o Response to environmental stress – certain proteins
help a bacterium to survive an environmental stress
o Cell division – some proteins are needed for cell division
- Common points where regulation of gene expression occurs in
bacteria:
14.1: Overview of transcriptional regulation
- Influencing the rate of transcription is the most common way to
regulate bacterial gene expression
- Regulatory proteins that bind to DNA and affect the transcription rate
o Repressor – binds to DNA, inhibits transcription
o Activator – binds to DNA, increases the rate of transcription
o Negative control – transcriptional regulation by a repressor
o Positive control – transcriptional regulation by an activator
- Small effector molecules also play a critical role in transcriptional regulation do not
bind to DNA binds to a repressor/activator conformational change, influences the
binding of the protein to the DNA
- The regulatory proteins have two binding sites: where it bind to DNA and to the effector
o Inducer – increases the rate of transcription can bind to repressor to prevent it
from binding to the DNA, can
bind to activator to cause it to
bind to DNA inducible
genes are regulated this way
o Corepressor – binds to a
repressor, causing the protein
to bind to DNA
o Inhibitor – bind to activator,
prevents it from binding to
DNA
Repressible genes
are regulated by
corepressors/inhibitors
2
Simone Zweers
Reference: Brooker, Genetics: Analysis and prinicples, 7th edition
Chapter 14: Gene regulation in bacteria
1
, Genetics summary – VU BMS 2020/2021
Simone Zweers
Reference: Brooker, Genetics: Analysis and prinicples, 7th edition
- Gene regulation is the phenomenon in which the level of gene
expression can vary under different conditions
- Constitutive genes are unregulated genes always expression
encode proteins that are continuously needed for the survival of
the bacterium
- Common processes regulated at the genetic level:
o Metabolism – some proteins function in the metabolism of
small molecules for example enzymes that are only
required when the sugars are present in the environment of
the bacterium
o Response to environmental stress – certain proteins
help a bacterium to survive an environmental stress
o Cell division – some proteins are needed for cell division
- Common points where regulation of gene expression occurs in
bacteria:
14.1: Overview of transcriptional regulation
- Influencing the rate of transcription is the most common way to
regulate bacterial gene expression
- Regulatory proteins that bind to DNA and affect the transcription rate
o Repressor – binds to DNA, inhibits transcription
o Activator – binds to DNA, increases the rate of transcription
o Negative control – transcriptional regulation by a repressor
o Positive control – transcriptional regulation by an activator
- Small effector molecules also play a critical role in transcriptional regulation do not
bind to DNA binds to a repressor/activator conformational change, influences the
binding of the protein to the DNA
- The regulatory proteins have two binding sites: where it bind to DNA and to the effector
o Inducer – increases the rate of transcription can bind to repressor to prevent it
from binding to the DNA, can
bind to activator to cause it to
bind to DNA inducible
genes are regulated this way
o Corepressor – binds to a
repressor, causing the protein
to bind to DNA
o Inhibitor – bind to activator,
prevents it from binding to
DNA
Repressible genes
are regulated by
corepressors/inhibitors
2
