Epigenetic Modification Sensing

Tamunotonye Jumbo – B.Eng. (in view)

Department of Chemical Engineering, University of Portharcourt, Choba Nigeria.

Abstract

Epigenome is the data set of all the changes that occurs in the DNA and to the DNA associated protein (histone).

Epigenetic modifications are restorable alterations in the chemical or physical changes in the substance consisting of DNA and protein within a chromosome. This substance is known as chromatin. There are two main types of epigenetic modifications:

• DNA methylation – Adding Methyl to the DNA strings.
• Histone tails alteration – Alteration in DNA associated protein.

Epigenetic modifications causes various forms of diseases and health conditions which includes: lupus, asthma, diabetes, rett syndrome, α-thalassemia, X-linked syndrome, Alzheimer’s disease, Rubinstein-Taybi syndrome, Parkinson’s disease and Coffin-Lowry syndrome, cancer and neurological disorders. However, epigenetic modifications could be detected by:

• Pyrosequencing analysis: this provides overview of the methylation pattern and it also allows for the measurement of the methylation level of individual CpG dinucletodes. It analyzes any CpG site of interest.
• Bisulfite conversion: In this method, a DNA sample is treated with sodium bisulfite resulting in the deamination of unmethylated cytosine to uracil and allowing the distinction between cytosine and methylated cytosine via sequencing.
• DNADNA enzyme digest:This method is based on the use of DNA endonucleases which do not cut methylated DNA.

• Identify modified-histone interacting proteins: Immunoprecipitation and WB analyses are used in combination for the identification of histone interacting proteins. Co-immunoprecipitation of histone-binding protein complexes requires the enzymatic processing of chromatin to generate single nucleosome units.
• Detect histone modifications: Immunoblot analysis including dot blots and WB are used to validate antibodies specificity or to access histone mark plentifulness.
• Determine the genomic location of histone marks: Chromatin immunoprecipitation (ChIP) is used in combination with PCR, next generation sequencing (NGS).