Hjorth J P, Meisler M, Nielsen J T
Genetics. 1979 Jul;92(3):915-30. doi: 10.1093/genetics/92.3.915.
Several investigated bank vole populations are polymorphis for the number of salivary amylase loci, and individual chromosomes may carry one, two or three linked amylase structural genes. In the present study, we have used bank vole stocks homozygous for different chromosomes to investigate the relationship between amylase production and gene number. By measuring the amylase activity in parotid glands and the percentage of amylase protein in saliva, we have been able to demonstrate that the amount of salivary amylase is directly proportional to the proposed gene number. The paper also describes the allele, AmySu, which codes for a heat-labile salivary amylase. The relative amounts of the heat-labile isozyme have been determined in different heterozygotes containing this allele, and these results also support the multiple locus model. Finally, a stock devoid of salivary amylase activity was established. Animals from this strain have, however, a protein in the parotid glands and in saliva that is very similar to amylase in molecular weight, amino acid composition and in its binding to glycogen and cyclohepta-amylose. In genetic crosses, the protein segregates as an amylase allele. Therefore, this protein, encoded by the functionally null allele AmyN, may represent an incorrectly processed amylase precursor.
在对一些社鼠种群的研究中发现，唾液淀粉酶基因座的数量存在多态性，个体染色体可能携带一个、两个或三个连锁的淀粉酶结构基因。在本研究中，我们使用了对不同染色体纯合的社鼠种群，来研究淀粉酶产生与基因数量之间的关系。通过测量腮腺中的淀粉酶活性以及唾液中淀粉酶蛋白的百分比，我们能够证明唾液淀粉酶的量与推测的基因数量成正比。本文还描述了编码热不稳定唾液淀粉酶的等位基因AmySu。已在含有该等位基因的不同杂合子中测定了热不稳定同工酶的相对含量，这些结果也支持多基因座模型。最后，建立了一个缺乏唾液淀粉酶活性的种群。然而，来自该品系的动物在腮腺和唾液中有一种蛋白质，其分子量、氨基酸组成以及与糖原和环庚糊精的结合情况都与淀粉酶非常相似。在遗传杂交中，这种蛋白质作为一个淀粉酶等位基因分离。因此，由功能无效等位基因AmyN编码的这种蛋白质可能代表一种加工错误的淀粉酶前体。
