<P> Noncoding RNAs are functional RNA molecules that are not translated into protein . Examples of noncoding RNA include ribosomal RNA, transfer RNA, Piwi - interacting RNA and microRNA . </P> <P> MicroRNAs are predicted to control the translational activity of approximately 30% of all protein - coding genes in mammals and may be vital components in the progression or treatment of various diseases including cancer, cardiovascular disease, and the immune system response to infection . </P> <P> Cis - regulatory elements are sequences that control the transcription of a nearby gene . Many such elements are involved in the evolution and control of development . Cis - elements may be located in 5' or 3' untranslated regions or within introns . Trans - regulatory elements control the transcription of a distant gene . </P> <P> Promoters facilitate the transcription of a particular gene and are typically upstream of the coding region . Enhancer sequences may also exert very distant effects on the transcription levels of genes . </P>

List functions of sections of dna that do not code for proteins