Histone-Modifying Enzymes

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Histone-Modifying Enzymes, the sites for modification are marked in color.
Histone-Modifying Enzymes, the sites for modification are marked in color.

The packaging of the eukaryotic genome into highly condensed chromatin makes it inaccessible to the factors required for gene transcription, DNA replication, recombination and repair. Eukaryotes have developed intricate mechanisms to overcome this repressive barrier imposed by the chromatin. It is composed of an octamer of the four core histones (H3, H4, H2A, H2B) around which 147 base pairs of DNA are wrapped. Several distinct classes of enzyme can modify histones at multiple sites[1]. The figure on the right enlists those histone-modifying enzymes whose specificity has been determined. There are at least eight distinct types of modifications found on histones (see the legend box on the top left of the figure). Enzymes have been identified for acetylation[2], methylation[3], demethylation[4], phosphorylation[5], ubiquitination[6], sumoylation[7], ADP-ribosylation[8] , deimination[9][10], and proline isomerization[11]. For a detailed example of histone modifications in transcription regulation see RNA polymerase control by chromatin structure and table Influence of modifications on gene expression in mammalian cells.

[edit] References

  1. ^ Kouzarides T. Cell. (2007) Chromatin Modifications and Their Function. 128(4):693-705
  2. ^ Sterner, D.E., and Berger, S.L. (2000). Acetylation of histones and transcription-related factors. Microbiol. Mol. Biol. Rev. 64, 435–459
  3. ^ Zhang, Y., and Reinberg, D. (2006). Transcription regulation by histone methylation: interplay between different covalent modifications of the core histone tails. Genes Dev. 15, 2343–2360
  4. ^ Klose RJ, Zhang Y (2007). "Regulation of histone methylation by demethylimination and demethylation". Nat. Rev. Mol. Cell Biol. 8 (4): 307–18. doi:10.1038/nrm2143. PMID 17342184. 
  5. ^ Nowak, S.J., and Corces, V.G. (2004). Phosphorylation of histone H3: a balancing act between chromosome condensation and transcriptional activation. Trends Genet. 20, 214–220
  6. ^ Shilatifard, A. (2006). Chromatin modifications by methylation and ubiquitination: implications in the regulation of gene expression. Annu. Rev. Biochem. 75, 243–269
  7. ^ Nathan, D., Ingvarsdottir, K., Sterner, D.E., Bylebyl, G.R., Dokmanovic, M., Dorsey, J.A., Whelan, K.A., Krsmanovic, M., Lane, W.S., Meluh, P.B., et al. (2006). Histone sumoylation is a negative regulator in Saccharomyces cerevisiae and shows dynamic interplay with positiveacting histone modifications. Genes Dev. 20, 966–976
  8. ^ Hassa, P.O., Haenni, S.S., Elser, M., and Hottiger, M.O. (2006). Nuclear ADP-ribosylation reactions in mammalian cells: where are we today and where are we going? Microbiol. Mol. Biol. Rev. 70, 789–829
  9. ^ Cuthbert, G.L., Daujat, S., Snowden, A.W., Erdjument-Bromage, H., Hagiwara, T., Yamada, M., Schneider, R., Gregory, P.D., Tempst, P., Bannister, A.J., and Kouzarides, T. (2004). Histone deimination antagonizes arginine methylation. Cell 118, 545–553
  10. ^ Wang, Y., Wysocka, J., Sayegh, J., Lee, Y.H., Perlin, J.R., Leonelli, L., Sonbuchner, L.S., McDonald, C.H., Cook, R.G., Dou, Y., et al. (2004). Human PAD4 regulates histone arginine methylation levels via demethylimination. Science 306, 279–283
  11. ^ Nelson, C.J., Santos-Rosa, H., and Kouzarides, T. (2006). Proline isomerization of histone H3 regulates lysine methylation and gene expression. Cell 126, 905–916

[edit] See also