[Relationship between amplicon composition and cytologic type of structures containing amplified DNA in murine P388 cells with multiple drug resistance].

Previously, we showed that, development of multidrug resistance (MDR) in mouse P388 leukemia cells, is often associated with the appearance of newly-formed chromosome-like structures that contain amplified copies of the mdrl gene. In the present study, we compared amplicon content in P388 sublines showing different types of these structures. A strong correlation between the formation of specific acentric markers consisting of two identical arms and the absence of the sorcin gene co-amplification was found. In all the sublines containing other types of chromosome-like structures, the sorcin gene is co-amplified.