Aspects of this topic are discussed in the following places at Britannica.
...the 5′ end of the mRNA, a modified guanine nucleotide, called a cap, is added. Noncoding nucleotide sequences called introns are excised from the RNA at this stage in a process called intron splicing. Molecular complexes called spliceosomes, which are composed of proteins and RNA, have RNA sequences that are complementary to the junction between introns and adjacent coding regions called...
in heredity: Mechanisms of mutation )...or it occurs at an inappropriate time because of alterations somewhere in the regulatory region. Fourth, mutations within introns that affect the specific nucleotide sequences that direct intron splicing may result in an mRNA that still contains an intron. When translated, this extra RNA will almost certainly be meaningless at the protein level, and its extra length will lead to a...
in heredity: Regulation of gene expression )Following the transcription of DNA into RNA, a process of editing and splicing takes place in which noncoding nucleotide sequences called introns are excised from the primary transcript, resulting in functional mRNA. For most genes this is a routine step in the production of mRNA, but in some genes there are alternative ways to splice the primary transcript, resulting in different mRNAs, which...
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