Elferink C J, Srivastava G, Maguire D J, Borthwick I A, May B K, Elliott W H
J Biol Chem. 1987 Mar 25;262(9):3988-92.
Reports to date have led to the conclusion that there are isozymes for 5-aminolevulinate synthase in the liver and erythroid tissue of chicken. Indeed, the existence of a multigene family for chicken 5-aminolevulinate synthase has been proposed. We find no evidence to support these proposals. In this work we show that 5-aminolevulinate synthase mRNA from chicken liver and reticulocytes is identical as determined by RNase mapping and primer extension studies and that the 5-aminolevulinate synthase protein from these tissues is the same size as judged by immunoblot analysis. We also show that a single mRNA species for 5-aminolevulinate synthase is present in chicken liver, reticulocytes, brain, and heart and an avian erythroblastosis virus-transformed chicken erythroblast cell line. Southern analysis shows the presence of only one gene copy for 5-aminolevulinate synthase in the chicken haploid genome. Overall, these results lead to the conclusion that in chickens 5-aminolevulinate synthase is encoded by a unique gene and is expressed as a single mRNA species in all tissues.
迄今为止的报告得出结论，鸡的肝脏和红细胞组织中存在5-氨基乙酰丙酸合酶的同工酶。实际上，有人提出鸡5-氨基乙酰丙酸合酶存在一个多基因家族。但我们没有找到支持这些说法的证据。在这项研究中，我们通过核糖核酸酶图谱分析和引物延伸研究表明，鸡肝脏和网织红细胞中的5-氨基乙酰丙酸合酶信使核糖核酸是相同的，并且通过免疫印迹分析判断，这些组织中的5-氨基乙酰丙酸合酶蛋白大小相同。我们还表明，鸡肝脏、网织红细胞、脑、心脏以及禽成红细胞增多症病毒转化的鸡成红细胞细胞系中都存在一种单一的5-氨基乙酰丙酸合酶信使核糖核酸。Southern分析表明，鸡单倍体基因组中仅存在一个5-氨基乙酰丙酸合酶基因拷贝。总体而言，这些结果得出结论，在鸡中，5-氨基乙酰丙酸合酶由一个独特的基因编码，并在所有组织中作为单一的信使核糖核酸物种表达。
