1.Defects in the encoding of histone-modifying proteins (Chp 6 and 12 wk 1)
Histone modification (e.g., histone acetylation and deacetylation, alterations in chromatin): Chromatin compaction and organization help to regulate gene expression, determining and maintaining cell identity. Chromatin structure must be controlled in self-renewing and differentiated cells in cell renewal systems. For example, there are differences in chromatin structure in stem cells and terminally differentiated cells
are chemical modifications of DNA sequences that alter the expression of genes, resulting in disease and phenotypical variations (upon genetics)
types of epigenetic modifications
> DNA modification
> histone modification
> Microribonucleic acids (miRNAs) or mature miRNAs
> specific environmental or non-genetic factors, such as diet and exposure to certain chemicals can affect epigenetic
Histone modifications- in diverse biological processes such as transcriptional activation/inactivation, chromosome packaging, and DNA damage/repair.
Histone modifications (e.g. histone acetylation and deacetylation, chromatin alterations)- Chromatin compaction and organization help to regulate gene expression, determining and maintaining cell identity
quantitative detection of various histone modifications- would provide useful information for a better understanding of epigenetic regulation of cellular processes and the development of histone modifying enzyme-targeted drugs.
Histone Modification- Results:
> Histone acetylation and deacetylation
> alterations in chromatin
2. Epigenetics and (45) its role on human development. (chp 6)
the study of influences on gene expression that occur without a DNA change.
diseases and other phenotypic variation are caused by mechanisms other than changes in the DNA sequences—termed epigenetics (“upon genetics”).1Epigenetics is the study of heritable changes in gene expression or phenotype caused by mechanisms other than changes in DNA sequences. Epigenetic modifications can cause individuals with the same DNA sequences (such as identical twins) to have different disease profiles
3. Totipotent cells
the zygote and early embryonic cells
Totipotent stem cells mean that they can produce an entire organism like fertilized oocyte
What are totipotent stem cell
They are stem cell that can give rise to any and all cell of the human body.
They can give rise to a entire organism.
They cells are found on the first round of replication when the sperm and egg unite or at the very earliest stage of development++.
and (49) its ability to differentiate into any type of cell
50. Prader-Willi syndrome and – missing the PATERNALLY imprinted copy of chromosome 15,
Prader-Willi syndrome-features include short stature, hypotonia, small hands and feet, obesity, mild to moderate mental retardation, and hypogonadism
behavioral characteristics of prader willi
Compulsivity (especially with food)
Difficulty with changes in routine
10-20% young adults develop psychosis
4. Angelman syndrome? – loss of the maternal copy of UBE3A
2 major causes of angelman
phenotype of angelman syndrome
severe developmental delay
major seizure problem
fascinated with water
Angelman syndrome- same 4-Mb deletion, inherited from the mother, causes Angelman syndrome, which is characterized by severe mental retardation, seizures, and an ataxic gait.
Deletions in Prader-Willi and Angelman Syndromes are identical and indistinguishable at the DNA level.
Gene responsible for Anglemman syndrome encodes a ligase- involved in protein degradation during brain development.
This gene is only active on the chromosome copy inherited from the mother.
A maternally transmitted deletion removes- the only active copies of these Angelman Syndrome genes, producing the features of Prader Willi syndrome.
5. 5-Azacytidine and the(44) treatment of cancer (Chap 6 & Chp 12- wk 1)
What does 5-azaC do to Dcm? Inhibits Dcm. Dcm becomes covalently trapped to DNA & degraded
What were the 3 effects of 5-azaC tested?
1. On DNA methylation
2. Bacterial growth
3. Site specific methylation
4. On transcriptome changes
If "aza" is added to E.Coli in increasing concentrations, what happens? Un-methylated DNA will increase proportionally (Since Dcm is inhibited)
How does high conc. of Aza affect bacterial growth? High conc. of Aza inhibits bacterial growth (after 2 hours)
a demethylating agent, has been used as a therapeutic drug in the treatment of leukemia and myelodysplastic syndrome
5-azacytidine (which reverses the effects of DNA methyltransferases [DNMTs]), have proven effective in reactivating silenced tumor-suppressor genes in the treatment of selected cancers
6. the role of inactive MLH1 in the development of some forms of inherited colon cancer.
A major cause of one form of inherited colon cancer (hereditary nonpolyposis colorectal cancer [HNPCC]) is the methylation of the
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- Submitted On 15 Feb, 2020 12:36:33