Ino80 subfamily

The archetype of the Ino80 subfamily is the Ino80 protein from S cerevisiae. Further members have been identified by sequence similarity in fungi, plants and animals 1. Ino80p was first isolated through its role in transcriptional regulation of inositol biosynthesis 2, 3 and forms part of the large complex 4. This complex is notable not only because it can reposition nucleosomes, but also because it is the only known Snf2 family-related complex able to separate DNA strands in a traditional helicase assay 4. However, the Ino80 complex contains two RuvB-like helicase subunits which may assist in strand separation.

The human INO80 complex has recently been shown to contain many proteins homologous to subunits, including the RuvB-like helicases, and to be capable of mobilising mononucleosomes 5.

Ino80p deleted strains are sensitive to DNA damaging agents, and recent studies have implicated Ino80p directly in the events of double stranded break repair 6, 7, perhaps for the eviction of nucleosomes in the vicinity of the break 8. However, other remodelling complexes such as Swr1, RSC and SWI/SNF may also be participants in other steps of the repair pathway (reviewed in 9).

names associated with subfamily members
1: Bakshi, R., T. Prakash, et al. (2004). In silico characterization of the INO80 subfamily of SWI2/SNF2 chromatin remodeling proteins. Biochem Biophys Res Commun 320(1): 197-204. PubMed
2: Bachhawat, N., Q. Ouyang, et al. (1995). Functional characterization of an inositol-sensitive upstream activation sequence in yeast. A cis-regulatory element responsible for inositol-choline mediated regulation of phospholipid biosynthesis. J Biol Chem 270(42): 25087-95. PubMed
3: Ebbert, R., A. Birkmann, et al. (1999). The product of the SNF2/SWI2 paralogue INO80 of Saccharomyces cerevisiae required for efficient expression of various yeast structural genes is part of a high-molecular-weight protein complex. Mol Microbiol 32(4): 741-51. PubMed
4: Shen, X., G. Mizuguchi, et al. (2000). A chromatin remodelling complex involved in transcription and DNA processing. Nature 406(6795): 541-4. PubMed
5: Jin, J., Y. Cai, et al. (2005). A Mammalian Chromatin Remodeling Complex with Similarities to the Yeast INO80 Complex. J Biol Chem 280(50): 41207-12. PubMed
6: Morrison, A. J., J. Highland, et al. (2004). INO80 and gamma-H2AX interaction links ATP-dependent chromatin remodeling to DNA damage repair. Cell 119(6): 767-75. PubMed
7: van Attikum, H., O. Fritsch, et al. (2004). Recruitment of the INO80 complex by H2A phosphorylation links ATP-dependent chromatin remodeling with DNA double-strand break repair. Cell 119(6): 777-88. PubMed
8: Tsukuda, T., A. B. Fleming, et al. (2005). Chromatin remodelling at a DNA double-strand break site in Saccharomyces cerevisiae. Nature 438(7066): 379-83. PubMed
9: Downs, J. A. and J. Cote (2005). Dynamics of chromatin during the repair of DNA double-strand breaks. Cell Cycle 4(10): 1373-6. PubMed