A frameshift mutation at the junction of an IS1 insertion within lacZ restores beta-galactosidase activity via formation of an active lacZ-IS1 fusion protein.
A frameshift mutation at the junction of an IS1 insertion within lacZ restores beta-galactosidase activity via formation of an active lacZ-IS1 fusion protein.
复制标题
lacZ 内 IS1 插入连接处的移码突变通过形成活性 lacZ-IS1 融合蛋白来恢复 β-半乳糖苷酶活性。
DOI：
10.1016/0022-2836(85)90427-9
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发表时间：
1985
影响因子：
5.6
通讯作者：
J. Miller
中科院分区：
文献类型：
--
作者：
M. Malamy;P. Rahaim;C. S. Hoffman;D. Baghdoyan;M. O'Connor;J. Miller
插入IS1元件导致β-半乳糖苷酶活性丧失，这种插入对操纵子远端基因的表达产生严重的极性影响。除了这些性质外，突变的lacZ：：IS1-MS319还具有自发或经移码诱变剂ICR-191处理后回复到Lac+(Ts)的独特性质；这种回复保留了IS1元件。在编码β-半乳糖苷酶C末端的序列末端18个核苷酸的第4338位，我们已经确定了IS1与半乳糖苷酶的整合位点。ICR-191促进Lac+的逆转是由于位于flacZ和IS1交界处的GGG序列丢失了G残基所致。结果形成了一个活性的、但对温度敏感的LacZ-IS1融合蛋白，该融合蛋白包含来自IS1的6个氨基酸，它们取代了编码bylacZ的6个氨基酸。MS319中的IS1元件是ISO-IS1家族的新成员，我们将其命名为IS1T。
The insertion of IS1 elements intolacZresults in the loss of β-galactosidase activity, and such insertions exert a severe polar effect on the expression of the distal genes of the operon. In addition to these properties, the mutationlacZ::IS1-MS319 has the unique property of reversion to Lac+(ts) spontaneously or after treatment with the frameshift mutagen ICR-191; such revertants retain the IS1 element. We have determined that the site of integration of IS1 intolacZis at position 4338, 18 nucleotides from the end of the sequence encoding the C-terminus of β-galactosidase. Reversion to Lac+promoted by ICR-191 results from the loss of a G residue from a GGG sequence located at the junction oflacZand IS1. As a result an active, but temperature-sensitive,lacZ-IS1 fusion protein is formed containing six amino acids derived from IS1 which replace six amino acids encoded bylacZ. The IS1 element in MS319 is a new member of the iso-IS1 family, which we designate IS1T.