Medugno Lina, Florio Francesca, De Cegli Rossella, Grosso Michela, Lupo Angelo, Costanzo Paola, Izzo Paola
Dipartimento di Biochimica e Biotecnologie Mediche, Università di Napoli Federico II, Via S. Pansini 5, 80131 Napoli, Italy.
Gene. 2005 Oct 10;359:35-43. doi: 10.1016/j.gene.2005.06.021.
Transcription factors belonging to the Krüppel-like zinc finger family of proteins participate in the regulation of cell differentiation and development. Although many of these proteins have been identified, little is known about their structure and function. We recently purified ZNF224, a new Krüppel-like zinc finger protein, that contains a Krüppel-associated box (KRAB) domain at the NH2 terminus, and 19 Cys2-His2 zinc-finger domains at the COOH terminus. Using chromatin immunoprecipitation and transient transfection assays, we demonstrate that ZNF224 binds in vivo to the distal promoter of the aldolase A gene and represses its transcription. The results of transient co-transfection experiments show that ZNF224-mediated transcription repression requires the 45-amino acid long KRAB A domain. The ability of KRAB-containing ZNF224 protein to repress transcription depends on specific interaction with the KAP-1 co-repressor molecule. Finally, using selective treatment with the HDAC1 inhibitor trichostatin A, we demonstrate that ZNF224-mediated repression requires histone deacetylases.
属于Krüppel样锌指蛋白家族的转录因子参与细胞分化和发育的调控。尽管已鉴定出许多此类蛋白，但对其结构和功能却知之甚少。我们最近纯化了一种新的Krüppel样锌指蛋白ZNF224，它在NH2末端含有一个Krüppel相关框（KRAB）结构域，在COOH末端含有19个Cys2-His2锌指结构域。通过染色质免疫沉淀和瞬时转染实验，我们证明ZNF224在体内与醛缩酶A基因的远端启动子结合并抑制其转录。瞬时共转染实验结果表明，ZNF224介导的转录抑制需要45个氨基酸长的KRAB A结构域。含KRAB的ZNF224蛋白抑制转录的能力取决于与KAP-1共抑制分子的特异性相互作用。最后，通过用HDAC1抑制剂曲古抑菌素A进行选择性处理，我们证明ZNF224介导的抑制需要组蛋白去乙酰化酶。
