Thomsen K K, Hjorth J P, Nielsen J T
Biochem Genet. 1984 Apr;22(3-4):257-73. doi: 10.1007/BF00484228.
The expression of pancreatic amylase in the mouse exhibits pronounced genetic variation. Congenic lines with various amylase complexes on a common C3H/As background have different numbers and forms of isoenzymes. The relative ratio of these isoenzymes may vary, as does the overall production of pancreatic amylase, which in some lines is three- to fourfold higher than in others. DNA from a number of lines was digested with endonucleases and hybridized to an amylase cDNA probe. The restriction patterns from inbred stocks and the corresponding congenic lines are identical, demonstrating that the majority of (if not all) amylase-like DNA sequences is found within the amylase complex. Congenic lines with specific amylase expression, for instance, in enzyme production, show different restriction patterns, whereas three lines with the same amylase phenotype have a uniform pattern. Most of the variation in amylase expression is represented among congenic lines derived from Danish mice. A comparison of such lines with others of remote geographic origin reveals that the restriction patterns of the "Danish" lines have by far the highest degree of resemblance. This observation seems to exclude major rearrangements within the amylase complex as the cause of the differences in enzyme expression, which instead are likely to be due to variation in regulatory elements associated with the active structural amylase genes in the complex.
小鼠胰腺淀粉酶的表达呈现出显著的遗传变异。在常见的C3H/As背景上带有各种淀粉酶复合体的近交系，其同工酶的数量和形式各不相同。这些同工酶的相对比例可能会有所变化，胰腺淀粉酶的总体产量也是如此，在某些品系中，其产量比其他品系高出三到四倍。用核酸内切酶消化多个品系的DNA，并与淀粉酶cDNA探针杂交。近交系及其相应近交同类系的限制性酶切图谱是相同的，这表明大多数（如果不是全部）淀粉酶样DNA序列存在于淀粉酶复合体内。具有特定淀粉酶表达的近交同类系，例如在酶产量方面，呈现出不同的限制性酶切图谱，而具有相同淀粉酶表型的三个品系则具有一致的图谱。淀粉酶表达的大部分变异存在于源自丹麦小鼠的近交同类系中。将这些品系与其他地理来源较远的品系进行比较发现，“丹麦”品系的限制性酶切图谱相似度最高。这一观察结果似乎排除了淀粉酶复合体内的主要重排是酶表达差异的原因，相反，这些差异可能是由于与该复合体中活性结构淀粉酶基因相关的调控元件的变异所致。
