THE CYTOLOGICAL MANIFESTATION OF GENE AMP LIFICATION IN MULTIDRUG-RESISTANT MOUSE LEUKEMIA P388 SUBLINES IS CORRELATED WITH AMPLICON CONTENT

Previously, we showed that, development of multidrug resistance (MDR) in mouse P388 leukemia cells, is often associated with the appearance of newly-formed chromosomelike structures that contain amplified copie s of the mdr1 gene. In the present study, we compared amplicon content in P388 subline showing different types of these structures. A strong correlation between the formation of specific acentric markers consis ting of two identical arms and the absence of the sorcin gene coamplif ication was found. In all the sublines containing other types of shrom osomelike structures; the sorcin gene is coamplified.