Differential activity of DNA replication origins located on the human chromosome band 9p22

There is scanty knowledge concerning initiation activity of cell type-specific DNA replication origins (oris) subject to regulation during development. At the same time, the knowledge on the subject can serve as an important reference for both the epigenetic developmental program revealing and identifying the features of this program in the course of development. Here we attempted to extend our knowledge on the subject on the example of the IFNA2 locus oris located in an AT-rich isochore on the human chromosome band 9p22. By Q-PCR, we measured the activity of two oris in cell lines originating from epithelium of the cervix (HeLa) and the early precursor of neuronal cell (HEK-293), and compared with their activity in an immortalized fibroblast cell line (CH). Using these three lines as a model, we have demonstrated for the first time the great epigenetic plasticity of oris located in a mammalian genetic locus (IFNA2). Therefore, this locus can be recommended as a convenient model for studying the epigenetic regulation of DNA replication.