Kalamajka Rainer, Hahnen Silke, Cavalar Markus, Töpsch Sonja, Weier Dagmar, Peterhänsel Christoph
Aachen University, Institute for Biology I, 52056 Aachen, Germany.
Plant Mol Biol. 2003 Jun;52(3):669-78. doi: 10.1023/a:1024843819307.
Expression of genes necessary to perform C4 photosynthesis in maize is activated by light. It is not known how this activation is regulated on the chromatin level in vivo. We analysed alterations in the chromatin structure of the promoter of the C4-specific isoform of phosphoenolpyruvate carboxylase (PEPC) after illumination of seedlings. A protocol was established that facilitates the preparation of nuclei from maize leaves with intact chromatin structure and resistance to DNA degradation during prolonged incubation at high temperatures. The presence of non-spliced transcripts from the C4-PEPC gene in the nuclei was demonstrated by RT-PCR. The chromatin was partially digested with restriction endonucleases. Quantitative PCR analyses revealed a clear increase in the accessibility of the promoter chromatin to restriction dependent on illumination of the seedlings. The data indicate chromatin reorganization at the C4-PEPC promoter during activation.
玉米中进行C4光合作用所需基因的表达受光激活。目前尚不清楚这种激活在体内染色质水平上是如何调控的。我们分析了幼苗光照后磷酸烯醇式丙酮酸羧化酶（PEPC）的C4特异性同工型启动子的染色质结构变化。建立了一种方案，该方案有助于从具有完整染色质结构且在高温下长时间孵育时对DNA降解具有抗性的玉米叶片中制备细胞核。通过RT-PCR证明细胞核中存在来自C4-PEPC基因的未剪接转录本。用限制性内切酶对染色质进行部分消化。定量PCR分析显示，依赖于幼苗光照，启动子染色质对限制性酶切的可及性明显增加。数据表明激活过程中C4-PEPC启动子处的染色质重组。
