Avtor/Urednik		Albà, M. Mar; Santibáñez-Koref, Mauro F.; Hancock, John M.
Naslov		The comparative genomics of polyglutamine repeats: extreme differences in the codon organization of repeat-encoding regions between mammals and Drosophila
Tip		članek
Vol. in št.		Letnik 52, št. 3
Leto izdaje		2001
Obseg		str. 249-259
ISSN		0022-2844 - Journal of molecular evolution
Jezik		eng
Abstrakt		Polyglutamine repeats within proteins are common in eukaryotes and are associated with neurological diseases in humans. Many are encoded by tandem repeats of the codon CAG that are likely to mutate primarily by replication slippage. However, a recent study in the yeast Saccharomyces cerevisiae has indicated that many others are encoded by mixtures of CAG and CAA which are less likely to undergo slippage. Here we attempt to estimate the proportions of polyglutamine repeats encoded by slippage-prone structures in species currently the subject of genome sequencing projects. We find a general excess over random expectation of polyglutamine repeats encoded by tandem repeats of codons. We nevertheless find many repeats encoded by nontandem codon structures. Mammals and Drosophila display extreme opposite patterns. Drosophila contains many proteins with polyglutamine tracts but these are generally encoded by interrupted structures. These structures may have been selected to be resistant to slippage. In contrast, mammals (humans and mice) have a high proportion of proteins in which repeats are encoded by tandem codon structures. In humans, these include most of the triplet expansion disease genes.
Proste vsebinske oznake		analiza genomov glutaminske ponovitve evolucija genoma genome analysis glutamine repeats genome evolution