Gumucio D L, Wiebauer K, Dranginis A, Samuelson L C, Treisman L O, Caldwell R M, Antonucci T K, Meisler M H
J Biol Chem. 1985 Nov 5;260(25):13483-9.
The two isozymes of pancreatic amylase in mouse strain YBR/Ki are encoded by closely linked genes which are independently regulated. We have isolated these two pancreatic amylase genes, Amy-2.1 and Amy-2.2, from a cosmid library of YBR/Ki genomic DNA and compared the nucleotide sequences of coding regions with the amino acid sequences of the protein isozymes. Transcripts of both genes were also isolated from a pancreatic cDNA library and partially sequenced. The results demonstrate that Amy-2.1 encodes the A1 isozyme of YBR/Ki pancreatic amylase, while Amy- 2.2 encodes the insulin-dependent B1 isozyme. Similarities of restriction maps and nucleotide sequences suggest that Amy-2.1 is closely related to the active Amy-2a gene previously isolated from strain A/J (Schibler, U., Pittet, A.-C., Young, R. A., Hagenbüchle, O., Tosi, M., Gellman, S., and Wellauer, P. K. (1982) J. Mol. Biol. 155, 247-266). Expression of Amy-2.2 may be limited to strain YBR/Ki. The inactive Amy-X gene from A/J (Schibler, U., Pittet, A.-C., Young, R. A., Hagenbüchle, O., Tosi, M., Gellman, S., and Wellauer, P. K. (1982) J. Mol. Biol. 155, 247-266) is apparently a null allele of Amy-2.2. An additional amylase gene from YBR/Ki has been identified as a pancreatic amylase pseudogene which diverged between sixteen and thirty-two million years ago. The pancreatic amylase subfamily in strain YBR/Ki thus consists of two active genes and one pseudogene. The low rate of amylase production in YBR/Ki pancreas, relative to that of other inbred strains, can be accounted for by the lower number of gene copies in this strain. Comparison of pancreatic amylase genes from different inbred strains provides evidence for several duplication and deletion events during the recent evolution of this chromosome region.
小鼠品系YBR/Ki中的两种胰腺淀粉酶同工酶由紧密连锁且独立调控的基因编码。我们从YBR/Ki基因组DNA的黏粒文库中分离出了这两个胰腺淀粉酶基因Amy-2.1和Amy-2.2，并将编码区的核苷酸序列与蛋白质同工酶的氨基酸序列进行了比较。这两个基因的转录本也从胰腺cDNA文库中分离出来并进行了部分测序。结果表明，Amy-2.1编码YBR/Ki胰腺淀粉酶的A1同工酶，而Amy-2.2编码胰岛素依赖性B1同工酶。限制性图谱和核苷酸序列的相似性表明，Amy-2.1与先前从A/J品系中分离出的活性Amy-2a基因密切相关（施布勒，U.，皮特，A.-C.，杨，R. A.，哈根布勒，O.，托西，M.，盖尔曼，S.，和韦劳尔，P. K.（1982年）《分子生物学杂志》155，247 - 266）。Amy-2.2的表达可能仅限于YBR/Ki品系。来自A/J的无活性Amy-X基因（施布勒，U.，皮特，A.-C.，杨，R. A.，哈根布勒，O.，托西，M.，盖尔曼，S.，和韦劳尔，P. K.（1982年）《分子生物学杂志》155，247 - 266）显然是Amy-2.2的一个无效等位基因。已鉴定出YBR/Ki的另一个淀粉酶基因为胰腺淀粉酶假基因，它在1600万至3200万年前发生了分化。因此，YBR/Ki品系中的胰腺淀粉酶亚家族由两个活性基因和一个假基因组成。相对于其他近交系，YBR/Ki胰腺中淀粉酶的低产量可归因于该品系中基因拷贝数较少。对不同近交系胰腺淀粉酶基因的比较为该染色体区域近期进化过程中的几次重复和缺失事件提供了证据。
