6533b85afe1ef96bd12b8bdb

RESEARCH PRODUCT

Evolution of chromatin-remodeling complexes: comparative genomics reveals the ancient origin of "novel" compensasome genes.

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Dosage compensation in Drosophila is mediated by a complex, called compensasome, com- posed of at least five proteins and two noncoding RNAs. Genes encoding compensasome proteins have been collectively named male-specific lethals or msls. Recent work showed that three of the Drosophila msls (msl-3, mof, and mle) have an ancient origin. In this study, I describe likely orthologues of the two re- maining msls, msl-1 and msl-2, in several inverte- brates and vertebrates. The MSL-2 protein is the only one found in Drosophila and vertebrate genomes that contains both a RING finger and a peculiar type of CXC domain, related to the one present in Enhancer of Zeste proteins. MSL-1 also contains two evolu- tionarily conserved domains: a leucine zipper and a second characteristic region, described here for the first time, which I have called the PEHE domain. These two domains are present in the likely ortho- logues of MSL-1 as well as in other genes in several invertebrate and vertebrate species. Although it can- not be excluded that the compensasome complex is a recent evolutionary novelty, these results shows that all msls are found in mammals, suggesting that pro- tein complexes related to the compensasome may be present in mammalian species. Metazoans that lack several of the msls, such as Caenorhabditis elegans, cannot contain compensasomes. The evolutionary relationships of the compensasome and the NuA4 complex, another chromatin-remodeling complex that contains related subunits, are discussed.