Only 2% of the genome codes for proteins. What does the rest do? What is its structure? One of the most intriguing and unknown regions in the eukaryotic genome is the centromere. IQFR and CMBSO researchers have recently shown that centromeric sequences of organisms as distant in the evolutionary tree as fruit flies and humans are able to fold in vitro forming the same type of secondary structure, known as the “i-motif”. The presence of these structures in such distant organisms suggests that they may be involved in the structural organization of the centromere. If this were the case, the centromeric DNA could have been selected during evolution not for its primary sequence, but for its capability to form this non-canonical structure, the “i-motif”.
This work is the result of a collaboration with our colleague and friend Alfredo Villasante, to whose memory it is dedicated.
M. Garavís, N. Escaja, V. Gabelica, A. Villasante and C. González. Centromeric alpha-satellite DNA adopts dimeric i-motif structures capped by AT Hoogsteen base pairs. Chemistry-A Eur. J., 21, 9816-9824, 2015. doi: 10.1002/chem.201500448 (artículo del mes SBE, junio 2015)
M. Garavís, M. Méndez-Lago, V. Gabelica, S. L. Whitehead G. González, and A. Villasante. The structure of an endogenous Drosophila centromere reveals the prevalence of tandemly repeated sequences able to form i-motifs. Sci. Rep., 5, 13307, 2015. doi: 10.1038/srep13307
