Transcriptional - These mechanisms prevent transcription. Posttranscriptional - These mechanisms control or regulate mRNA after it has been produced.

Slides:



Advertisements
Similar presentations
Epigenetics Epigenetics - Heritable changes in gene expression that operate outside of changes in DNA itself - stable changes in gene expression caused.
Advertisements

Differential Gene Expression
Gregor Mendel ( ) DNA (gene) mRNA Protein Transcription RNA processing (splicing etc) Translation Folding Post translational modifications Peptides/amino.
Transcriptional-level control (10) Researchers use the following techniques to find DNA sequences involved in regulation: – Deletion mapping – DNA footprinting.
Methylation, Acetylation and Epigenetics
Regulation of Gene Expression
Lecture #8Date _________ n Chapter 19~ The Organization and Control of Eukaryotic Genomes.
Hybridization Diagnostic tools Nucleic acid Basics PCR Electrophoresis
All the cells in the organism have the same DNA DNA is packed together with histones and other proteins into chromatin. Chromatin is a highly dynamic.
Chapter 19: Eukaryotic Genomes Most gene expression regulated through transcription/chromatin structure Most gene expression regulated through transcription/chromatin.
Control of Eukaryotic Genes
Control of Gene Expression Eukaryotes. Eukaryotic Gene Expression Some genes are expressed in all cells all the time. These so-called housekeeping genes.
 Eukaryotic Gene Expression.  Transduction  Transformation.
Introns and Exons DNA is interrupted by short sequences that are not in the final mRNA Called introns Exons = RNA kept in the final sequence.
Regulation of Gene Expression
Epigenetics of Human Marie Černá Lecture No 426-H.
Eukaryotic Gene Control. Developmental pathways of multicellular organisms: All cells of a multicellular organism start with the same complement of DNA.
Introduction to Epigenetics
Regulation of Gene Expression Eukaryotes
Chapter 11 Regulation of Gene Expression. Regulation of Gene Expression u Important for cellular control and differentiation. u Understanding “expression”
GENE REGULATION ch 18 CH18 Bicoid is a protein that is involved in determining the formation of the head and thorax of Drosophila.
Eukaryotic Genome & Gene Regulation The entire genome of the eukaryotic organism is present in every cell of the organism. Although all genes are present,
AP Biology Control of Eukaryotic Genes.
Regulating Eukaryotic Gene Expression. Why change gene expression? Different cells need different components Responding to the environment Replacement.
AP Biology Control of Eukaryotic Genes. AP Biology The BIG Questions… How are genes turned on & off in eukaryotes? How do cells with the same genes differentiate.
Ch 15 -.Gene Regulation  Prokaryote Regulation Operon * not found in eukaryotes Operon * not found in eukaryotes Regulator gene = codes for repressor.
Gene Expression. Cell Differentiation Cell types are different because genes are expressed differently in them. Causes:  Changes in chromatin structure.
AP Biology Control of Eukaryotic Genes.
 7.2: Transcription & gene expression.  Gene expression Proteins regulate the expression of genes. Prokaryotes express genes in response to their environment.
Control of Eukaryotic Genome
Eukaryotic Gene Control. Gene Organization: Chromatin: Complex of DNA and Proteins Structure base on DNA packing.
GENE REGULATION RESULTS IN DIFFERENTIAL GENE EXPRESSION, LEADING TO CELL SPECIALIZATION Eukaryotic DNA.
AP Biology Eukaryotic Genome Control Mechanisms for Gene expression.
Histone Methylation Marks : Permanent or Reversible?
3B2: Gene Expression Draw 5 boxes on your paper.
Chapter 19 The Organization & Control of Eukaryotic Genomes.
Molecules and mechanisms of epigenetics. Adult stem cells know their fate! For example: myoblasts can form muscle cells only. Hematopoetic cells only.
Epigenetics Abira Khan. What is Epigenetics?  Histone code: Modifications associated with transcriptional activation- primarily methylation and acetylation-would.
How is gene expression in eukaryotes accomplished ?
Control of Eukaryotic Genes (Ch. 19) The BIG Questions… How are genes turned on & off in eukaryotes? How do cells with the same genes differentiate to.
The Importance of Epigenetic Phenomena in Regulating Activity of the Genetic Material Sin Chan.
Gene Regulation, Part 2 Lecture 15 (cont.) Fall 2008.
Epigenetics of cancer Vilja ja Mia.
Eukaryotic Gene Regulation
Eukaryotic Genome & Gene Regulation
Gene Expression.
GENE REGULATION in Eukaryotic Cells
Regulation of Gene Expression
Last Week’s Reading Assignments
Introduction to Genetic Analysis
Regulation of gene Expression in Prokaryotes & Eukaryotes
Gene Regulation Ability of an organisms to control which genes are present in response to the environment.
Topic 7: The Organization and Control of Eukaryotic Genomes
SGN22 Regulation of Eukaryotic Genomes (CH 15.2, 15.3)
Eukaryotic Gene Expression
Concept 18.2: Eukaryotic gene expression can be regulated at any stage
Gene Regulation.
Daily Warm-Up Thursday, January 9th
Review Warm-Up What is the Central Dogma?
Epigenetics Heritable alteration of gene expression without a change in nucleotide sequence.
Epigenetics modification
Same genes, different phenotypes
Figure 2 Histone acetylation regulates gene expression
Environmental epigenetics of asthma: An update
Eukaryotic Gene Regulation
A Role for Epigenetics in Psoriasis: Methylated Cytosine–Guanine Sites Differentiate Lesional from Nonlesional Skin and from Normal Skin  Johann E. Gudjonsson,
Gene Expression II Kim Foreman, PhD
Epigenetics.
Presentation transcript:

Transcriptional - These mechanisms prevent transcription. Posttranscriptional - These mechanisms control or regulate mRNA after it has been produced. Translational - These mechanisms prevent translation. They often involve protein factors needed for translation. Posttranslational - These mechanisms act after the protein has been produced.

epigenetics is the study of heritable changes in gene expression or cellular phenotype caused by mechanisms other than changes in the underlying DNA sequence – hence the name epi- (Greek: επί- over, above, outer) -genetics. It refers to functionally relevant modifications to the genome that do not involve a change in the nucleotide sequence. Examples of such modifications are DNA methylation and histone modification, both of which serve to regulate gene expression without altering the underlying DNA sequence. (Wikipedia) zs Epigenetics primer w&NR=1&feature=endscreen

tion/ Nutrition and epigenetics SAM e: same same Epigentic inheritance example X inactivation

Transcriptional Acetylation/deacetylation of DNA Condensation of DNA involves coiling around proteins called histones. Acetylation is when acetyl groups (- COCH3) are attached to lysines in the histone tails. This reduces condensation and promotes transcription because the transcription machinery has better access to the DNA.

Biological roles of acetylation Histone acetylation and deacetylation have been implicated in many biological processes, such as cell differentiation and survival, double-strand DNA break repair, cell cycle progression, malignant transformation, cardiac function and remodeling, and plant acclimation to cold stress. Also, studies have linked the proliferative capacity of many solid tumors to the histone acetylation status. The loss of acetylation at Lys16 of H4 is a common characteristic of human cancer. Hence, HATs and HDACs have become some of the most promising targets in cancer therapy.

switches-discovered-to-decline-significantly- with-age/

Role of DNA methylation is to silence the gene: role-of-methylation-in-gene-expression-1070 Biological roles of DNA methylation In the mammalian genome, about 70% of CpG dinucleotides are methylated. Many of the remaining nonmethylated CpGs are in CpG islands typically found in functional promoter regions. DNA methylation has long been viewed as an epigenetic marker of gene repression and plays important roles in heterochromatin formation, long-term silencing of repetitive elements, X-chromosome inactivation and in the establishment and maintenance of imprinted genes.

Histone Methylation Histone methylation is a more stable modification than acetylation Biological roles of histone methylation Recent studies have implicated histone methylation in the maintenance of embryonic stem (ES) cells in the undifferentiated state, arginine demethylimination in transcriptional repression, histone lysine demethylases in transcriptional regulation, cancer cell proliferation and normal neuronal function, and the loss of trimethylation at Lys20 of H4 in human cancer. Studies have suggested that histone demethylation and deacetylation are tightly coupled.

MI How methylation silences genes

Post transcriptional modification:RNA processing. Addition of polyAAA tail and 5-methyl gunaosine cap. Failure to do this results in rapid degradation of the pre mRNA YA mRNA processing

Post transcriptional modification:RNA modification: exons and introns. hill.com/sites/ /student_view0/chapter16/animation _-_exon_shuffling.html

In human cells, about 40-60% of the genes are known to exhibit alternative splicing. RNA-Splicing.html

Translational Control; microRNAs 9pROnSD-A