Sequence analysis and compositional properties of untranslated regions of human mRNAs

A detailed computer analysis of the untranslated regions, 5'-UTR and 3'-UTR, of human mRNA sequences is reported. The compositional properties of these regions, compared with those of the corresponding coding regions, indicate that 5'-UTR and 3'-UTR are less affected by the isochore compartmentalization than the corresponding third codon positions of mRNAs. The presence of higher functional constraints in 5'-UTR is also reported. Dinucleotide analysis shows a depletion of CpG and TpA in both sequences. A search for significant sequence motifs using the WORDUP algorithm reveals the patterns already known to have a functional role in the mRNA UTR, and several other motifs whose functional roles remain to be demonstrated. This type of analysis may be particularly useful for guiding site-directed mutagenesis experiments. In addition, it can be used for assessing the nature of anonymous sequences now produced in large amounts in megabase sequencing projects.