The coding region can be modified in order to regulate gene expression.
Alkylation is one form of regulation of the coding region. The gene that would have been transcribed can be silenced by targeting a specific sequence. The bases in this sequence would be blocked using alkyl groups, which create the silencing effect.
While the regulation of gene expression manages the abundance of RNA or protein made in a cell, the regulation of these mechanisms can be controlled by a regulatory sequence found before the open reading frame begins in a strand of DNA. The regulatory sequence will then determine the location and time that expression will occur for a protein coding region.
RNA splicing ultimately determines what part of the sequence becomes translated and expressed, and this process involves cutting out introns and putting together exons. Where the RNA spliceosome cuts, however, is guided by the recognition of splice sites, in particular the 5' splicing site, which is one of the substrates for the first step in splicing. The coding regions are within the exons, which become covalently joined together to form the mature messenger RNA.