Jones J M, Keller S A, Samuelson L C, Osborn L, Rosenberg M P, Meisler M H
Department of Human Genetics, University of Michigan Medical School, Ann Arbor 48109-0618.
Nucleic Acids Res. 1989 Aug 25;17(16):6613-23. doi: 10.1093/nar/17.16.6613.
Two distinct mouse amylase cDNAs, corresponding to the genes Amy-1.1 and Amy-1.2, have been isolated from a YBR/Ki parotid cDNA library. A cosmid clone containing the intact Amy-1.1 gene from strain YBR/Ki, including both the parotid and liver promoters, was transferred to the germ line of C57BL/6J mice. Two independent transgenic lines were produced. The transferred genes are organized as a 4-copy autosomal locus in line Tg518 and an 8-copy Y-linked locus in line Tg2736. Serum of both transgenic lines contained high levels of the AMY1B isozyme encoded by the transferred gene. Transcripts were detected in liver and, at a lower level, in several other tissues including white and brown fat. The anticipated expression in parotid was not observed. Constructs containing 270 or 540 bp of the 5' flanking region of the parotid promoter, cloned upstream of the chloramphenicol acetyltransferase (CAT) structural gene, were also not expressed in transgenic mice. The results suggest that sequences located more than 5 kb upstream of the Amy-1 parotid promoter and/or more than 10 kb downstream from the structural gene are required for parotid-specific expression. The results also demonstrate that non-parotid sources can produce a normal level of AMY1 in serum. Liver is the probable source of AMY1 in serum of these transgenic mice.
从YBR/Ki腮腺cDNA文库中分离出了两个不同的小鼠淀粉酶cDNA，它们分别对应Amy-1.1和Amy-1.2基因。一个包含来自YBR/Ki品系完整Amy-1.1基因的黏粒克隆，包括腮腺和肝脏启动子，被转入C57BL/6J小鼠的生殖系。产生了两个独立的转基因系。在Tg518系中，转入的基因以4拷贝常染色体位点的形式存在，而在Tg2736系中则以8拷贝Y连锁位点的形式存在。两个转基因系的血清中都含有高水平的由转入基因编码的AMY1B同工酶。在肝脏中检测到了转录本，在包括白色和棕色脂肪在内的其他几种组织中也检测到了较低水平的转录本。未观察到预期的腮腺表达。含有腮腺启动子5'侧翼区270或540 bp的构建体，克隆在氯霉素乙酰转移酶（CAT）结构基因上游，在转基因小鼠中也未表达。结果表明，腮腺特异性表达需要位于Amy-1腮腺启动子上游超过5 kb和/或结构基因下游超过10 kb的序列。结果还表明，非腮腺来源可以在血清中产生正常水平的AMY1。肝脏可能是这些转基因小鼠血清中AMY1的来源。
