An important event in gene expression is the covalent modification of histone proteins. We have found that the mammalian transcriptional repressor Sin3 (mSin3) exists in a complex with histone deacetylases HDAC1 and HDAC2. Consistent with the observation that mSin3-mediated repression of transcription involves the modification of histone polypeptides, we found that the mSin3-containing complex includes polypeptides that tether the mSin3 complex to core histone proteins. In addition, two novel mSin3-associated polypeptides, SAP18 and SAP30, were identified. We isolated a cDNA encoding human SAP18 and found that SAP18 is a component of an mSin3-containing complex in vivo. Moreover, we demonstrate a direct interaction between SAP18 and mSin3. SAP18 represses transcription in vivo when tethered to the promoter, consistent with the ability of SAP18 to interact with mSin3.
Zhang, Y., Iratni, R., Erdjument-Bromage, H., Tempst, P., & Reinberg, D. (1997). Histone deacetylases and SAP18, a novel polypeptide, are components of a human Sin3 complex. Cell, 89(3), 357–364. https://doi.org/10.1016/S0092-8674(00)80216-0