Question

What is DNA methylation? Describe how this mechanism regulates the expression of genes. What can happen when the DNA is hyper-methylated? Pick and describe a disease that results from DNA hyper-methylation.

Answer 1

DNA methylation is a process, in that methyl group added to DNA molecules. this action changes the DNA activity without changing the sequences. In gene, promoter DNA methylation acts as a repress gene transcription.DNA methylation regulates gene expression by inhibiting transcription factor binding to DNA, that time DNA methylation in the genome changes occurs as a result of a dynamic process involving in de novo DNA methylation and demethylation. when DNA was hypermythlated it increase the epigenetic methylation of cytosine to form 5-methylcytosine the reaction occurs and categorised by DNA methyltransferases.
Bloom's syndrome is a rare autosomal recessive disorder by short stature and predisposition to the development of cancer and genomic instability, in which cells' ability for the integrity of DNA is impaired. In Bloom's syndrome there is a chromosomal breakage happen with mutator phenotype. This gene disorder as a DNA helicase, gene plays a major role in immunoglobulin mutation the people will lack mutated antibodies. These antibodies have a low affinity to the eliciting antigene somatic hypermutation happen cause accumulation it dominate the mature antibody response. The process of mutation and selection in protective antibodies causes DNA replication that linked to transcription.