Samuelson L C, Wiebauer K, Gumucio D L, Meisler M H
Department of Human Genetics, University of Michigan, Ann Arbor 48109-0618.
Nucleic Acids Res. 1988 Sep 12;16(17):8261-76. doi: 10.1093/nar/16.17.8261.
The human genes encoding salivary amylase (AMY1) and pancreatic amylase (AMY2) are nearly identical in structure and sequence. We have used ribonuclease protection studies to identify the functional gene copies in this multigene family. Riboprobes derived from each gene were hybridized to RNA from human pancreas, parotid and liver. The sizes of the protected fragments demonstrated that both pancreatic genes are expressed in pancreas. One of the pancreatic genes, AMY2B, is also transcribed at a low level in liver, but not from the promoter used in pancreas. AMY1 transcripts were detected in parotid, but not in pancreas or liver. Unexpected fragments protected by liver RNA led to the discovery that the 5' regions of the five human amylase genes contain a processed gamma-actin pseudogene. The promoter and start site for transcription of AMY1 are recently derived from the 3' untranslated region of gamma-actin. In addition, insertion of an endogenous retrovirus has interrupted the gamma-actin pseudogene in four of the five amylase genes.
编码唾液淀粉酶（AMY1）和胰腺淀粉酶（AMY2）的人类基因在结构和序列上几乎相同。我们利用核糖核酸酶保护研究来鉴定这个多基因家族中的功能基因拷贝。从每个基因衍生的核糖探针与来自人类胰腺、腮腺和肝脏的RNA杂交。受保护片段的大小表明两个胰腺基因均在胰腺中表达。其中一个胰腺基因AMY2B在肝脏中也有低水平转录，但并非源自胰腺中使用的启动子。在腮腺中检测到了AMY1转录本，但在胰腺或肝脏中未检测到。肝脏RNA保护的意外片段导致发现五个人类淀粉酶基因的5'区域包含一个加工过的γ-肌动蛋白假基因。AMY1转录的启动子和起始位点最近源自γ-肌动蛋白的3'非翻译区。此外，内源性逆转录病毒的插入中断了五个淀粉酶基因中四个基因的γ-肌动蛋白假基因。
