Plasterk R H, Vollering M, Brinkman A, Van de Putte P
Cell. 1984 Jan;36(1):189-96. doi: 10.1016/0092-8674(84)90088-6.
The Mu mom gene is transcribed only when DNA is methylated by Dam; this methylation dependence is determined by a region upstream of the gene containing three Dam-methylation sites. The mom operon contains two open reading frames, one of which codes for Mom. Experiments were done to find a function for the other reading frame; it is shown that it does not affect phage immunity or the regulation of mom expression. Deletion mapping and S1 nuclease mapping experiments identify the +1 of the mom mRNA: it is 45 bp downstream of the three Dam-methylation sites. Possible models for the short-distance transcription regulation by methylation are discussed. The mom promoter is surrounded by sequences that are shown to be homologous to the oriC region of E. coli. This suggests a relation between replication and methylation-dependent mom expression. It is shown however, that replication is not essential for mom expression.
Mu mom基因仅在Dam使DNA发生甲基化时才会转录；这种甲基化依赖性由基因上游包含三个Dam甲基化位点的区域决定。mom操纵子包含两个开放阅读框，其中一个编码Mom。开展了实验以寻找另一个阅读框的功能；结果表明它不影响噬菌体免疫或mom表达的调控。缺失图谱分析和S1核酸酶图谱分析实验确定了mom mRNA的+1位点：它位于三个Dam甲基化位点下游45 bp处。讨论了甲基化进行短距离转录调控的可能模型。mom启动子周围的序列与大肠杆菌oriC区域具有同源性。这表明复制与甲基化依赖性mom表达之间存在关联。然而，结果表明复制对于mom表达并非必不可少。
