Okada M, Hirose S
Department of Genetics, The Graduate University for Advanced Studies, National Institute of Genetics, Mishima, Shizuoka-ken, Japan.
Mol Cell Biol. 1998 May;18(5):2455-61. doi: 10.1128/MCB.18.5.2455.
GAGA factor is known to remodel the chromatin structure in concert with nucleosome-remodeling factor NURF in a Drosophila embryonic S150 extract. The promoter region of the Drosophila fushi tarazu (ftz) gene carries several binding sites for GAGA factor. Both the GAGA factor-binding sites and GAGA factor per se are necessary for the proper expression of ftz in vivo. We observed transcriptional activation of the ftz gene when a preassembled chromatin template was incubated with GAGA factor and the S150 extract. The chromatin structure within the ftz promoter was specifically disrupted by incubation of the preassembled chromatin with GAGA factor and the S150 extract. Both transcriptional activation and chromatin disruption were blocked by an antiserum raised against ISWI or by base substitutions in the GAGA factor-binding sites in the ftz promoter region. These results demonstrate that GAGA factor- and ISWI-mediated disruption of the chromatin structure within the promoter region of ftz activates transcription on the chromatin template.
已知GAGA因子可在果蝇胚胎S150提取物中与核小体重塑因子NURF协同重塑染色质结构。果蝇分节基因（ftz）的启动子区域带有多个GAGA因子结合位点。GAGA因子结合位点和GAGA因子本身对于ftz在体内的正常表达都是必需的。当预组装的染色质模板与GAGA因子和S150提取物一起孵育时，我们观察到ftz基因的转录激活。通过将预组装的染色质与GAGA因子和S150提取物一起孵育，ftz启动子内的染色质结构被特异性破坏。针对ISWI产生的抗血清或ftz启动子区域中GAGA因子结合位点的碱基替换均阻断了转录激活和染色质破坏。这些结果表明，GAGA因子和ISWI介导的ftz启动子区域内染色质结构的破坏激活了染色质模板上的转录。
