Chromosomal alterations of rat cell lines transformed by human adenovirus type-12 virion, whole DNA and left-end DNA fragments.

A normal rat cell line, 3Y1-B clone 1-6 (3Y1) and its adenovirus (Ad) type-12-transformed derivatives, W4 (transformed by Ad12 Virion), WY3 (transformed by Ad12 whole DNA), CY1-1 (transformed by the Ad12 EcoRI-C fragment, left 16.5%), GY1-1 (transformed by the Ad12 HindIII-G fragment, left 6.8%) and HY1 (transformed by the Ad12 Acd-H fragment, left 4.7%) were studied cytogenetically. 3Y1 and some of the transformed cell lines (W4, WY3 and GY1-1) were diploid or pseudodiploid, while others (CY1-1 and HY1) were hypotetraploid. A metacentric marker M1 was detected in GY1-1 cells and another marker M2 in W4 and CY1-1 cells at a high frequency. By the Giemsa banding technique, the metacentric markers M1 and M2 from these fully transformed cell lines were identified as isochromosomes derived from 1q (M1) and 3q (M2), respectively. On the other hand, the markers were detected only at a low frequency in incompletely transformed HY1 cells. However, hypersomy in chromosome No. 1 was observed at a high frequency in this cell line. It can be concluded that hypersomy of chromosomes No. 1 or 3 found in transformants and metacentric markers found in complete transformants are characteristic features in rat cells transformed by Ad12.