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Overview of gene regulation ?Definition: The process by which cells control the expression of genes.RNA sequencing (RNA-seq), microarrays.Helps fetus to harvest oxygen from maternal blood ?Gene regulation determines which globin polypeptides are made to become functional hemoglobin 2/17/2025 12 Living organisms grow and develop ?Gene regulation is an important process that allows organisms to proceed through developmental stages.Why we need control of gene expression ?All our body cells contain identical genetic instructions ?However, these cells appear very different ?Muscle cells, nerve cells and epithelial cells are different ?This morphological difference reflects a profound difference in gene expression 2/17/2025 4 Overview of gene regulation ?Red blood cells develop from cells which express oxygen carrying protein, haemoglobin.2/17/2025 5 Gene regulation in bacteria ?Most commonly occurs at the level of transcription ?Also, can control rate of translation ?Can be regulated at protein or post translation level Prokaryotic (Bacterial) gene regulation ?Responds to changes in the environment.Post-translation Levels of Gene Expression Control in Eukaryotic Cells 9 2/17/2025 10 Gene regulation in eukaryotes ?Cell differentiation: necessary to produce different cell types in an organism ?All of the organism's cells contain the same genome but express different proteomes due to gene regulation ?2/17/2025 3 Importance of gene regulation ?The regulation of gene expression plays a central role in development from a zygote to a multicellular organism ?Essential for cellular differentiation, development, and response to environmental changes.Different amounts of the same protein Gene regulation in eukaryotes 2/17/2025 11 Developmental gene regulation in mammals ?Example: Hemoglobin in fetal versus adult humans.Overview of gene regulation ?The expression of ?- galactosidase protein is induced by addition of lactose to the medium of E.coli.RNA processing, splicing, and stability (e.g., microRNAs, RNA-binding proteins).?Majority of genes regulated to ensure that proteins are produced at the correct time and amount.Eukaryotic Regulation ?Five primary levels of control: B. Cytoplasmic levels: 4.Translational control.Control of RNA synthesis (e.g., transcription factors, enhancers, silencers).ChIP-seq (Chromatin Immunoprecipitation), bisulfite sequencing.?CRISPR-Cas9 ????????????

Overview of gene regulation
❑Definition: The process by which cells control the expression of genes.
❑Gene regulation refers to the ability of cells to control their level of gene expression.
❑Majority of genes regulated to ensure that proteins are produced at the correct time
and amount.
❑Saves energy by producing only when needed.
❑Constitutive genes are unregulated and have essentially constant levels of
expression.
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Importance of gene regulation
❑The regulation of gene expression plays a central role in development
from a zygote to a multicellular organism
❑Essential for cellular differentiation, development, and response to
environmental changes.
❑Dysregulation can lead to diseases like cancer, diabetes, and genetic
disorders.
Why we need control of gene expression
❑All our body cells contain identical genetic instructions
❑However, these cells appear very different
❑Muscle cells, nerve cells and epithelial cells are different
❑This morphological difference reflects a profound difference in gene
expression
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Overview of gene regulation
❑Red blood cells develop from cells which express oxygen carrying
protein, haemoglobin. Other cells do not express haemoglobin.
❑Nerve cells express special proteins responsible for propagating
electrical signals. Other cells do not express these proteins.
❑Muscle cells express proteins which make up the contractile apparatus.
Other cells do not express these proteins.
Overview of gene regulation
❑The expression of β- galactosidase protein is induced by addition of
lactose to the medium of E.coli.
❑Analysis of lactose metabolism in E.coli led to the Operon theory.
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Gene regulation in bacteria
❑Most commonly occurs at the level of
transcription
❑Also, can control rate of translation
❑Can be regulated at protein or post
translation level
Prokaryotic (Bacterial) gene regulation
❑Responds to changes in the environment.
❑Example: Escherichia coli and lactose.
When lactose is available, two proteins are made:
▪ lactose permease: transports lactose into the cell.
▪ ꞵ- galactosidase: breaks down lactose.
❑When lactose levels drop, the proteins are no longer made.
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Living organisms use energy
❑ Gene regulation provides a way for cells to avoid wasting energy and to
make proteins only when they are needed.
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Eukaryotic Regulation
❑A variety of mechanisms.
❑Five primary levels of control:
A.Nuclear levels:
1.Chromatin structure.
2.Transcriptional control.
3.Posttranscriptional control.
Eukaryotic Regulation
❑Five primary levels of control:
B. Cytoplasmic levels:
4.Translational control.
5.Posttranslational control.
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Levels of Gene Regulation
❑ Transcriptional Level
▪ Control of RNA synthesis (e.g., transcription factors, enhancers, silencers).
❑ Post-Transcriptional Level
▪ RNA processing, splicing, and stability (e.g., microRNAs, RNA-binding proteins).
❑ Translational Level
▪ Control of protein synthesis (e.g., initiation factors, ribosome binding).
❑ Post-Translational Level
▪ Protein modification and degradation (e.g., phosphorylation, ubiquitination).
Mechanisms of Gene Regulation
❑ Transcriptional Regulation
▪ Promoters, enhancers, and silencers.
▪ Role of transcription factors (e.g., TATA box, zinc finger proteins).
❑ Epigenetic Regulation
▪ DNA methylation, histone modification, and chromatin remodeling.
❑ Non-Coding RNAs
▪ microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) in gene silencing.
❑ Feedback Loops
▪ Positive and negative feedback mechanisms.
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Gene regulation in eukaryotes
▪ Transcriptional regulation common
▪ RNA processing
▪ Translation
▪ Post-translation
Levels of Gene
Expression Control
in Eukaryotic Cells
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Gene regulation in eukaryotes
❑Cell differentiation: necessary to produce different cell types in
an organism
❑All of the organism’s cells contain the same genome but
express different proteomes due to gene regulation
▪ Different proteins
▪ Different amounts of the same protein
Gene regulation in eukaryotes
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Developmental gene regulation in mammals
❑Example: Hemoglobin in fetal versus adult humans.
▪ Fetal hemoglobin has a higher affinity for oxygen than adult
hemoglobin
▪ Helps fetus to harvest oxygen from maternal blood
❑Gene regulation determines which globin polypeptides are made to
become functional hemoglobin
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Living organisms grow and develop
❑Gene regulation is an important process that allows organisms
to proceed through developmental stages.
Techniques to Study Gene Regulation
❑Gene Expression Analysis
▪ RNA sequencing (RNA-seq), microarrays.
❑Epigenetic Tools
▪ ChIP-seq (Chromatin Immunoprecipitation), bisulfite sequencing.
❑CRISPR-Cas9
▪ Gene editing to study regulatory elements.
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Applications of Gene Regulation
❑ Medicine
▪ Gene therapy, personalized medicine.
❑ Agriculture
❑ Biotechnology
▪ Genetically modified organisms (GMOs) with improved traits.
▪ Production of recombinant proteins (e.g., insulin)