rRNA-like sequences in human mRNAs.

Many eukaryotic transcripts have been reported to contain sequences similar or complementary to ribosomal RNAs. Past computational and experimental analyses have suggested a possible functional role of such rRNA-like sequences in the regulation of translation. Here, we analysed the occurrence and abundance of rRNA-like sequences in human transcripts. Using the wealth of data from genome and EST sequences, our study indicates that mRNA sequences with long highly similar rRNA-like sequences are most likely artifacts. In contrast, analysis of the occurrence of 9-nt sequences covering the entire direct and complementary 18S human rRNA sequence, revealed that many of them are significantly over- or underrepresented, suggesting their possible involvement in post-transcriptional regulation of gene expression.