How may we enhance or facilitate transcription b What molecu

How may we enhance or facilitate transcription? (b) What molecular/biochemical process is primarily involved in setting epigenetic effects?

Solution

a. There are regions of the genome which increase or enhance transcription which is called as enhancers which are located upstream of a gene within the coding region of a gene. These regions are binding sequences or sites for the transcription factors. When a DNA binding protein binds to an enhancer, the shape of the DNA changes due to which it allows the interaction between the activators bound to the enhancer and the transcription factor bound to the promoter region and the RNA polymerase to occur.

b. Epigenetics refer to the complex interactions between the genome and the environment that are involved in the development and differentiation. Epigenetic modifications come in different flavours like DNA methylation and histone modifications which alter DNA accesibility and chromatin structure there by regulating patterns of gene expression.

In the differentiated cells the principal epigenetic tag is found in the form of DNA methylation where DNA is covalently attached with a methyl group at the C5 position of cytosine residues in CpG dinucleotide sequences. In the early embryogenesis, this methylation pattern is erased throughout the genome and then reestablished in all but CpG islands. Subsequent methylation of cytosines in CpG islands is associated with transcriptional repression.