Figure 1.

Characteristics of endogenous HDAC1, -2, and -3 immune complexes. (A) HeLa-S3 cell extract was immunoprecipitated (IP) by using anti-HDAC1, 2, or 3 antibodies or preimmune serum. Each immunoprecipitate was divided in two and one-half of the immunoprecipitate was incubated with 200 nM TPX prior to assaying for deacetylase activity (dpm). (B) Immunoblot of HDAC1, -2, and -3 binding a TPX-based affinity matrix. Equal amounts of HeLa-S3 cell extract were preincubated with (+) or without (−) 800 nM TPX for 20 min at 4°C and then incubated with K-trap affinity resin for 1 h at 4°C. Eluted proteins were separated by SDS/PAGE, transferred and immunoblotted by using the indicated antibody. (C) Anti-HDAC1, -2, or -3 immunoprecipitates (IP) from SV40 T-Ag Jurkat or HeLa-S3 cell extracts were tested for coprecipitation of associated HDACs by immunoblotting with the antibodies indicated.