1. Evidence for selection in evolution of alpha satellite DNA: the central role of CENP-B/pJ alpha binding region.
- Author
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Romanova LY, Deriagin GV, Mashkova TD, Tumeneva IG, Mushegian AR, Kisselev LL, and Alexandrov IA
- Subjects
- Animals, Base Sequence, Centromere genetics, Centromere metabolism, Centromere Protein B, Chromosomal Proteins, Non-Histone metabolism, DNA, Satellite metabolism, DNA-Binding Proteins genetics, DNA-Binding Proteins metabolism, Molecular Sequence Data, Sequence Alignment, Sequence Analysis, Autoantigens, Chromosomal Proteins, Non-Histone genetics, DNA, Satellite genetics, Evolution, Molecular
- Abstract
Conservation of DNA segments performing sequence-related functions is a landmark of selection and functional significance. Phylogenetic variability of alpha satellite and apparent absence of conserved regions calls its functional significance into question, even though sequence-specific alpha satellite-binding proteins pJ alpha and CENP-B have been discovered. Moreover, the function of pJ alpha is obscure and CENP-B binding satellite DNA, which is thought to participate in centromere formation, is found only in few species and not necessarily in all chromosomes. Analysis of alpha satellite evolution allows us to recognize the order in this variability. Here we report a new alpha satellite suprachromosomal family, which together with the four defined earlier, covers all known alpha satellite sequences. Although each family has its characteristic types of monomers, they all descend from two prototypes, A and B. We show that most differences between prototypes are concentrated in a short region (positions 35 to 51), which exists in two alternative states: it matches a binding site for pJ alpha in type A and the one for CENP-B in type B. Lower primates have only type A monomers whereas great apes have both A and B. The new family is formed by monomeric types almost identical to A and B prototypes, thus representing a living relic of alpha satellite. Analysis of these data shows that selection-driven evolution, rather than random fixation of mutations, formed the distinction between A and B types. To our knowledge, this is the first evidence for selection in any of the known satellite DNAs.
- Published
- 1996
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