Recurrent evolution of DNA-binding motifs in the Drosophila centromeric histone
AUTOR(ES)
Malik, Harmit S.
FONTE
The National Academy of Sciences
RESUMO
All eukaryotes contain centromere-specific histone H3 variants (CenH3s), which replace H3 in centromeric chromatin. We have previously documented the adaptive evolution of the Drosophila CenH3 (Cid) in comparisons of Drosophila melanogaster and Drosophila simulans, a divergence of ≈2.5 million years. We have proposed that rapidly changing centromeric DNA may be driving CenH3's altered DNA-binding specificity. Here, we compare Cid sequences from a phylogenetically broader group of Drosophila species to suggest that Cid has been evolving adaptively for at least 25 million years. Our analysis also reveals conserved blocks not only in the histone-fold domain but also in the N-terminal tail. In several lineages, the N-terminal tail of Cid is characterized by subgroup-specific oligopeptide expansions. These expansions resemble minor groove DNA binding motifs found in various histone tails. Remarkably, similar oligopeptides are also found in N-terminal tails of human and mouse CenH3 (Cenp-A). The recurrent evolution of these motifs in CenH3 suggests a packaging function for the N-terminal tail, which results in a unique chromatin organization at the primary constriction, the cytological marker of centromeres.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=122211Documentos Relacionados
- DNA-binding proteins and evolution of transcription regulation in the archaea.
- Rapid evolution of the DNA-binding site in LAGLIDADG homing endonucleases
- Identifying DNA-binding proteins using structural motifs and the electrostatic potential
- Improved detection of helix-turn-helix DNA-binding motifs in protein sequences.
- AT-hook motifs identified in a wide variety of DNA-binding proteins.
