RNA 聚合酶 II 转录起始
中文名称
通路描述
RNA 聚合酶 II 转录起始过程中，开放复合物暴露模板链至 RNA 聚合酶 II 酶的催化中心，促进第一个磷酸二酯键的形成，标志着转录起始。此过程导致 TFIIB 基础转录因子从起始复合物解离。开放转录起始复合物不稳定，可回转为闭合状态。该阶段需要 TFIIH 持续进行(d)ATP 水解。二核苷酸转录本与转录复合物结合不稳定，解离后形成终止产物。转录复合物也易受小寡核苷酸抑制。位于模板 -1 和 +1 位点的二核苷酸也可引导第一个磷酸二酯键形成，此反应不依赖基础转录因子 TFIIE 和 TFIIH，且不涉及开放复合物形成。此反应易受单链寡核苷酸抑制。
英文描述
Defective CP causes aceruloplasminemia (ACERULOP) Ceruloplasmin (CP), synthesised in the liver and secreted into plasma, is a copper-binding (6-7 atoms per molecule) glycoprotein involved in iron trafficking in vertebrates. CP is essential for SLC40A1 (ferroportin) stability at the cell surface, the protein that mediates iron efflux from cells. CP also possesses ferroxidase activity, which oxidises ferrous iron (Fe2+) to ferric iron (Fe3+) following its transfer out of the cell. Fe3+ can then be loaded on to extracellular transferrin which transports it around the body to sites where it is required. Iron is vital for many metabolic processes such as electron transport and the transport and storage of oxygen.
Defects in CP (or indeed SLC40A1) can lead to the phenotype of iron overload as seen in the disorder aceruloplasminemia (ACERULOP; MIM:604290). It is a rare autosomal recessive disorder of iron metabolism characterised by iron accumulation mainly in the brain, but also in liver, pancreas and retina. Patients develop retinal degeneration, diabetes mellitus and neurological disturbance. ACERULOP belongs to a group of disorders known as NBIA (neurodegeneration with brain iron accumulation), distinguishing it from hereditary hemochromatosis (serum iron is high but the brain is usually not affected) and from disorders of copper metabolism such as Menkes and Wilson disease (Harris et al. 1995, Kono 2012, Musci et al. 2014).
Defects in CP (or indeed SLC40A1) can lead to the phenotype of iron overload as seen in the disorder aceruloplasminemia (ACERULOP; MIM:604290). It is a rare autosomal recessive disorder of iron metabolism characterised by iron accumulation mainly in the brain, but also in liver, pancreas and retina. Patients develop retinal degeneration, diabetes mellitus and neurological disturbance. ACERULOP belongs to a group of disorders known as NBIA (neurodegeneration with brain iron accumulation), distinguishing it from hereditary hemochromatosis (serum iron is high but the brain is usually not affected) and from disorders of copper metabolism such as Menkes and Wilson disease (Harris et al. 1995, Kono 2012, Musci et al. 2014).
所含基因
1 个基因