Unique Functions of Repetitive Transcriptomes

• Published in: International Review of Cell and Molecular Biology Vol. 285; pp. 115 - 188
• Main Authors: Schumann, Gerald G., Gogvadze, Elena V., Osanai-Futahashi, Mizuko, Kuroki, Azusa, Münk, Carsten, Fujiwara, Haruko, Ivics, Zoltan, Buzdin, Anton A.
• Format: Book Chapter Journal Article
• Language: English
• Published: United States Elsevier Science & Technology 2010
• Subjects: Animals; APOBEC 3 proteins; Biotechnology - methods; Cellular biology; Evolution, Molecular; Gene delivery; Gene Expression Profiling; Genetic Techniques; Genome evolution; Genomic Instability - genetics; Humans; Models, Biological; Molecular biology; Regulatory Sequences, Nucleic Acid - genetics; Repetitive sequences; Repetitive Sequences, Nucleic Acid - genetics; Repetitive Sequences, Nucleic Acid - physiology; Retroelements - genetics; Retroelements - physiology; Retrotransposons; RNA interference; Transposable elements; Retrotransposons; Gene delivery; RNA interference; Repetitive sequences; APOBEC 3 proteins; Genome evolution; Transposable elements
• ISBN: 0123810477; 9780123810472
• ISSN: 1937-6448
• DOI: 10.1016/B978-0-12-381047-2.00003-7

Repetitive sequences occupy a huge fraction of essentially every eukaryotic genome. Repetitive sequences cover more than 50% of mammalian genomic DNAs, whereas gene exons and protein-coding sequences occupy only ~ 3% and 1%, respectively. Numerous genomic repeats include genes themselves. They generally encode “selfish” proteins necessary for the proliferation of transposable elements (TEs) in the host genome. The major part of evolutionary “older” TEs accumulated mutations over time and fails to encode functional proteins. However, repeats have important functions also on the RNA level. Repetitive transcripts may serve as multifunctional RNAs by participating in the antisense regulation of gene activity and by competing with the host-encoded transcripts for cellular factors. In addition, genomic repeats include regulatory sequences like promoters, enhancers, splice sites, polyadenylation signals, and insulators, which actively reshape cellular transcriptomes. TE expression is tightly controlled by the host cells, and some mechanisms of this regulation were recently decoded. Finally, capacity of TEs to proliferate in the host genome led to the development of multiple biotechnological applications.