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Simple repetitive sequences in the genome: structure and functional significance

Brahmachari, SK and Meera, G and Sarkar, PS and Balagurumoorthy, P and Tripathi, J and Raghavan, S and Shaligram, U and Pataskar, S (1995) Simple repetitive sequences in the genome: structure and functional significance. In: Electrophoresis, 16 (9). pp. 1705-1714.

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Official URL: http://www.ncbi.nlm.nih.gov/pubmed/8582360

Abstract

The current explosion of DNA sequence information has generated increasing evidence for the claim that noncoding repetitive DNA sequences present within and around different genes could play an important role in genetic control processes, although the precise role and mechanism by which these sequences function are poorly understood. Several of the simple repetitive sequences which occur in a large number of loci throughout the human and other eukaryotic genomes satisfy the sequence criteria for forming non-B DNA structures in vitro. We have summarized some of the features of three different types of simple repeats that highlight the importance of repetitive DNA in the control of gene expression and chromatin organization. (i) (TG/CA)n repeats are widespread and conserved in many loci. These sequences are associated with nucleosomes of varying linker length and may play a role in chromatin organization. These Z-potential sequences can help absorb superhelical stress during transcription and aid in recombination. (ii) Human telomeric repeat (TTAGGG)n adopts a novel quadruplex structure and exhibits unusual chromatin organization. This unusual structural motif could explain chromosome pairing and stability. (iii) Intragenic amplification of (CTG)n/(CAG)n trinucleotide repeat, which is now known to be associated with several genetic disorders, could down-regulate gene expression in vivo. The overall implications of these findings vis-à-vis repetitive sequences in the genome are summarized.

Item Type: Journal Article
Additional Information: Copy right of this article belongs to John Wiley and Sons.
Department/Centre: Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited: 13 Jan 2010 05:22
Last Modified: 13 Jan 2010 05:22
URI: http://eprints.iisc.ernet.in/id/eprint/25214

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